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Thursday, May 2, 2019

Islamic views on slavery

From Wikipedia, the free encyclopedia

Islamic views on slavery represent a complex and multifaceted body of Islamic thought, with various Islamic groups or thinkers espousing views on the matter which have been radically different throughout history. Slavery was a mainstay of life in pre-Islamic Arabia and surrounding lands. The Quran and the hadith (sayings of Muhammad) address slavery extensively, assuming its existence as part of society but viewing it as an exceptional condition and restricting its scope. Early Islamic dogma forbade enslavement of free members of Islamic society, including non-Muslims (dhimmis), and set out to regulate and improve the conditions of human bondage. The sharīʿah (divine law) regarded as legal slaves only those non-Muslims who were imprisoned or bought beyond the borders of Islamic rule, or the sons and daughters of slaves already in captivity. In later classical Islamic law, the topic of slavery is covered at great length. Slaves, be they Muslim or those of any other religion, were equal to their fellow practitioners in religious issues.
 
In theory, slavery in Islamic law does not have a racial or color component, although this has not always been the case in practice. Slaves played various social and economic roles, from domestic worker to highest-ranking positions in the government like Sultan. They created some great empires in history including the Ghaznavid Empire, Khwarazmian Empire, Delhi Sultanate, Mamluk Sultanate of Iraq and Mamluk Sultanate of Egpyt and Levant. Moreover, slaves were widely employed in irrigation, mining, pastoralism, and the army. Some rulers even relied on military and administrative slaves to such a degree that they were considered above from the general public and sometimes they seized power. In some cases, the treatment of slaves was so harsh that it led to uprisings, such as the Zanj Rebellion. However, this was an exception rather than the norm, as the vast majority of labor in the medieval Islamic world consisted of free, paid labour. For a variety of reasons, internal growth of the slave population was not enough to fulfill the demand in Muslim society. This resulted in massive importation, which involved enormous suffering and loss of life from the capture and transportation of slaves from non-Muslim lands.

The Arab slave trade was most active in West Asia, North Africa, and Southeast Africa. Muslim traders exported as many as 17 million slaves to the coast of the Indian Ocean, the Middle East, and North Africa. In the early 20th century (post World War I), slavery was gradually outlawed and suppressed in Muslim lands, largely due to pressure exerted by Western nations such as Britain and France. For example, Saudi Arabia and Yemen only abolished slavery in 1962 under pressure from Britain; Oman followed suit in 1970, and Mauritania in 1905, 1981, and again in August 2007. However, slavery claiming the sanction of Islam is documented presently in the predominantly Islamic countries of Chad, Mauritania, Niger, Mali, and Sudan.

Many early converts to Islam were the poor and former slaves. One notable example is Bilal ibn Rabah al-Habashi.

Slavery in pre-Islamic Arabia

Slavery was widely practiced in pre-Islamic Arabia, as well as in the rest of the ancient and early medieval world. The minority were white slaves of foreign extraction, likely brought in by Arab caravaners (or the product of Bedouin captures) stretching back to biblical times. Native Arab slaves had also existed, a prime example being Zayd ibn Harithah, later to become Muhammad's adopted son. Arab slaves, however, usually obtained as captives, were generally ransomed off amongst nomad tribes. The slave population increased by the custom of child abandonment (see also infanticide), and by the kidnapping, or, occasionally, the sale of small children. There is no conclusive evidence of the existence of enslavement for debt or the sale of children by their families; the late and rare accounts of such occurrences show them to be abnormal, Brunschvig states (According to Brockopp, debt slavery was persistent.) Free persons could sell their offspring, or even themselves, into slavery. Enslavement was also possible as a consequence of committing certain offenses against the law, as in the Roman Empire.

Two classes of slave existed: a purchased slave, and a slave born in the master's home. Over the latter the master had complete rights of ownership, though these slaves were unlikely to be sold or disposed of by the master. Female slaves were at times forced into prostitution for the benefit of their masters, in accordance with Near Eastern customs.

The historical accounts of the early years of Islam report that "slaves of non-Muslim masters ... suffered brutal punishments. Sumayyah bint Khayyat is famous as the first martyr of Islam, having been killed with a spear by Abū Jahl when she refused to give up her faith. Abu Bakr freed Bilal when his master, Umayya ibn Khalaf, placed a heavy rock on his chest in an attempt to force his conversion."

Slavery in the Quran

Bilal ibn Ribah (pictured, atop the Kaaba) an Ethiopian former slave, was appointed by Muhammad as the first official muezzin. He had been emancipated when Abu Bakr paid his ransom upon Muhammad's instruction. The image depicts an episode in January 630, when he became the first Muslim to proclaim adhan in Mecca.
The alms are only for the poor and the needy, and those who collect them, and those whose hearts are to be reconciled, and to free the slaves and the debtors, and for the cause of Allah, and (for) the wayfarer; a duty imposed by Allah. Allah is Knower, Wise.
The mainstream view is that the Quran accepts the institution of slavery. The word 'abd' (slave) is rarely used, being more commonly replaced by some periphrasis such as ma malakat aymanukum ("that which your right hands own"). However the meaning and translation of this term has been disputed. W.G. Clarence-Smith has highlighted the point of view of Ghulam Ahmed Pervez on this issue, who argued that the term is used in the past-tense in the Quran, thus signalling only those individuals who were already enslaved at the dawn of Islam. This slight change in tense is significant, as it allowed G.A. Parwez to argue that slavery was never compatible with the commandments of the Quran and is in fact outlawed by Quranic Law.

The mainstream view; however, is that the Qur'an recognizes the basic inequality between master and slave and the rights of the former over the latter. The historian Brunschvig states that from a spiritual perspective, "the slave has the same value as the free man, and the same eternity is in store for his soul; in this earthly life, failing emancipation, there remains the fact of his inferior status, to which he must piously resign himself."

According to Lewis, the Quran urges kindness to the slave and recommends their liberation by purchase or manumission. The freeing of slaves is recommended both for the expiation of sins and as an act of simple benevolence. It exhorts masters to allow slaves to earn or purchase their own freedom (manumission contracts)."

Slaves are mentioned in at least twenty-nine verses of the Qur'an, most of these are Medinan and refer to the legal status of slaves. The legal material on slavery in the Qur'an is largely restricted to manumission and sexual relations. According to Sikainga, the Qur'anic references to slavery as mainly contain "broad and general propositions of an ethical nature rather than specific legal formulations."

The Quran accepts the distinction between slave and free as part of the natural order and uses this distinction as an example of God's grace, regarding this discrimination between human beings as in accordance with the divinely established order of things. "The Qur'an, however, does not consider slaves to be mere chattel; their humanity is directly addressed in references to their beliefs, their desire for manumission and their feelings about being forced into prostitution. In one case, the Qur'an refers to master and slave with the same word, rajul. Later interpreters presume slaves to be spiritual equals of free Muslims. For example, verse 4:25 urges believers to marry 'believing maids that your right hands own' and then states: "The one of you is as the other," which the Jalaalayn interpret as "You and they are equal in faith, so do not refrain from marrying them." The human aspect of slaves is further reinforced by reference to them as members of the private household, sometimes along with wives or children. The Prophet ordered slave-owners to address their slaves by such euphemistic terms as "my boy" and "my girl" stemmed from the belief that God, not their masters, was responsible for the slave's status.

There are many common features between the institution of slavery in the Quran and that of neighboring cultures. However, the Quranic institution had some unique new features. Bernard Lewis states that the Qur'anic legislation brought two major changes to ancient slavery which were to have far-reaching effects: presumption of freedom, and the ban on the enslavement of free persons except in strictly defined circumstances. According to Brockopp, the idea of using alms for the manumission of slaves appears to be unique to the Quran, assuming the traditional interpretation of verses [Quran 2:177] and [Quran 9:60]. Similarly, the practice of freeing slaves in atonement for certain sins appears to be introduced by the Quran (but compare Exod 21:26-7). The forced prostitution of female slaves, a Near Eastern custom of great antiquity, is condemned in the Quran. Murray Gordon notes that this ban is "of no small significance." Brockopp writes: "Other cultures limit a master's right to harm a slave but few exhort masters to treat their slaves kindly, and the placement of slaves in the same category as other weak members of society who deserve protection is unknown outside the Qur'an. The unique contribution of the Qur'an, then, is to be found in its emphasis on the place of slaves in society and society's responsibility toward the slave, perhaps the most progressive legislation on slavery in its time."

According to Maurice Middleberg, "Sura 90 in the Quran states that the righteous path involves 'the freeing of slaves.'"

Muhammad's traditions

The corpus of hadith attributed to Muhammad follows the general lines of Quranic teaching on slavery and contains a large store of reports enjoining kindness toward slaves.

Murray Gordon characterizes Muhammad's approach to slavery as reformist rather than revolutionary. He did not set out to abolish slavery, but rather to improve the conditions of slaves by urging his followers to treat their slaves humanely and free them as a way of expiating one's sins. While some modern Muslim authors have interpreted this as indication that Muhammad envisioned a gradual abolition of slavery, Gordon argues that Muhammad instead assured the legitimacy of slavery in Islam by lending it his moral authority. Likely justifications for his attitude toward slavery included the precedent of Jewish and Christian teachings of his time as well as pragmatic considerations.

The most notable of Muhammad's slaves were: Safiyya bint Huyayy, whom he freed and married; Maria al-Qibtiyya, given to Muhammad by a Sassanid official, whom he freed and who may have become his wife; Sirin, Maria's sister, whom he freed and married to the poet Hassan ibn Thabit and Zayd ibn Harithah, whom Muhammad freed and adopted as a son.

Islamic jurisprudence

Traditional Islamic jurisprudence

Principles

In Islamic jurisprudence, slavery was theoretically an exceptional condition under the dictum The basic principle is liberty (al-'asl huwa 'l-hurriya), so that for a foundling or another person whose status was unknown freedom was presumed and enslavement forbidden. Lawful enslavement was restricted to two instances: capture in war (on the condition that the prisoner is not a Muslim), or birth in slavery. Islamic law did not recognize the classes of slave from pre-Islamic Arabia including those sold or given into slavery by themselves and others, and those indebted into slavery. Though a free Muslim could not be enslaved, conversion to Islam by a non-Muslim slave did not require that he or she then should be liberated. Slave status was not affected by conversion to Islam.

Treatment

In the instance of illness it would be required for the slave to be looked after. Manumission is considered a meritorious act. Based on the Quranic verse (24:33), Islamic law permits a slave to ransom himself upon consent of his master through a contract known as mukataba. Azizah Y. al-Hibri, a professor of Law specializing in Islamic jurisprudence, states that both the Qur'an and Hadith are repeatedly exhorting Muslims to treat the slaves well and that Muhammad showed this both in action and in words. Levy concurs, adding that "cruelty to them was forbidden." Al-Hibri quotes the famous last speech of Muhammad and other hadiths emphasizing that all believers, whether free or enslaved, are siblings. Lewis explains, "the humanitarian tendency of the Qur'an and the early caliphs in the Islamic empire, was to some extent counteracted by other influences," notably the practice of various conquered people and countries Muslims encountered, especially in provinces previously under Roman law. In spite of this, Lewis also states, "Islamic practice still represented a vast improvement on that inherited from antiquity, from Rome, and from Byzantium." Murray Gordon writes: "It was not surprising that Muhammad, who accepted the existing socio-political order, looked upon slavery as part of the natural order of things. His approach to what was already an age-old institution was reformist and not revolutionary. The Prophet had not in mind to bring about the abolition of slavery. Rather, his purpose was to improve the conditions of slaves by correcting abuses and appealing to the conscience of his followers to treat them humanely." The adoption of slaves as members of the family was common, according to Levy. If a slave was born and brought up in the master's household he was never sold, except in exceptional circumstances.

Sexual intercourse

In Islamic law (Sharia), Ma malakat aymanukum is the term for slaves or captives of war. The purchase of female slaves for sex was lawful from the perspective of Islamic law, and this was the most common motive for the purchase of slaves throughout Islamic history.

Al-Muminun 6 and Al-Maarij 30 both, in identical wording, draw a distinction between spouses and "those whom one's right hands possess", saying " أَزْوَاجِهِمْ أَوْ مَا مَلَكَتْ أَيْمَانُهُمْ" (literally, "their spouses or what their right hands possess"), while clarifying that sexual intercourse with either is permissible. Sayyid Abul Ala Maududi explains that "two categories of women have been excluded from the general command of guarding the private parts: (a) wives, (b) women who are legally in one's possession".

Concubinage

Slave women were required mainly as concubines and menials. A Muslim slaveholder was entitled by law to the sexual enjoyment of his slave women. While free women might own male slaves, they had no such right. The property of a slave was owned by his or her master unless a contract of freedom of the slave had been entered into, which allowed the slave to earn money to purchase his or her freedom and similarly to pay bride wealth. The marriage of slaves required the consent of the owner. Under the Hanafi and Shafi'i schools of jurisprudence male slaves could marry two wives, but the Maliki permitted them to marry four wives like the free men. According to the Islamic law, a male slave could marry a free woman but this was discouraged in practice. Islam permits sexual relations between a male master and his female slave outside marriage. This is referred to in the Qur'an as ma malakat aymanukum or "what your right hands possess". There are some restrictions on the master; he may not co-habit with a female slave belonging to his wife, neither can he have relations with a female slave if she is co-owned, or already married.

In ancient Arabian custom, the child of a freeman by his slave was also a slave unless he was recognized and liberated by his father. In theory, the recognition by a master of his offspring by a slave woman was optional in Islamic society, and in the early period was often withheld. By the High Middle Ages it became normal and was unremarkable in a society where the sovereigns themselves were almost invariably the children of slave concubines. The mother receives the title of "umm walad" (lit. mother of a child), which is an improvement in her status as she can no longer be sold. Among Sunnis, she is automatically freed upon her master's death, however for Shi'a, she is only freed if her child is still alive; her value is then deducted from this child's share of the inheritance. Lovejoy writes that as an umm walad, they attained "an intermediate position between slave and free" pending their freedom, although they would sometimes be nominally freed as soon as they gave birth.

There is no limit on the number of concubines a master may possess. However, the general marital laws are to be observed, such as not having sexual relations with the sister of a female slave. In Islam, "men are enjoined to marry free women in the first instance, but if they cannot afford the bridewealth for free women, they are told to marry slave women rather than engage in wrongful acts." One rationale given for recognition of concubinage in Islam is that "it satisfied the sexual desire of the female slaves and thereby prevented the spread of immorality in the Muslim community." A slave master could have sex with his female slave only while she was not married. This attempt to require sexual exclusivity for female slaves was rare in antiquity, when female slaves generally had no claim to an exclusive sexual relationship. According to Sikainga, "in reality, however, female slaves in many Muslim societies were prey for members of their owners' household, their neighbors, and their guests."

In Shiite jurisprudence it is unlawful for a master of a female slave to grant a third party the use of her for sexual relations. The Shiite scholar Shaykh al-Tusi stated:ولا يجوز إعارتها للاستمتاع بها لأن البضع لا يستباح بالإعارة "It is not permissible to loan (the slave girl) for enjoyment purpose, because sexual intercourse cannot be legitimate through loaning" and the Shiite scholars al-Muhaqiq al-Kurki, Allamah al-Hilli and Ali Asghar Merwarid made the following ruling: ولا تجوز استعارة الجواري للاستمتاع "It is not permissible to loan the slave girl for the purpose of sexual intercourse"

Under the legal doctrine of kafa'a(lit."efficiency"), the purpose of which was to ensure that a man should be at least the social equal of the woman he marries, a freedman is not as good as the son of a freedman, and he in turn not as good as the grandson of a freedman. This principle is pursued up to three generations, after which all Muslims are deemed equally free. Lewis asserts that since kafa'a "does not forbid unequal marriages", it is in no sense a "Muslim equivalent of Nuremberg Laws of Nazi Germany or the apartheid laws of South Africa. His purpose, he states, is not to try to set up a moral competition - to compare castration and apartheid as offenses against humanity."

Legal status

Within Islamic jurisprudence, slaves were excluded from religious office and from any office involving jurisdiction over others. Freed slaves are able to occupy any office within the Islamic government, and instances of this in history include the Mamluk who ruled Egypt for almost 260 years and the eunuchs who have held military and administrative positions of note. With the permission of their owners they are able to marry. Annemarie Schimmel, a contemporary scholar on Islamic civilization, asserts that because the status of slaves under Islam could only be obtained through either being a prisoner of war (this was soon restricted only to infidels captured in a holy war) or born from slave parents, slavery would be theoretically abolished with the expansion of Islam. Fazlur Rahman agrees, stating that the Qur'anic acceptance of the institution of slavery on the legal plane was the only practical option available at the time of Muhammad since "slavery was ingrained in the structure of society, and its overnight wholesale liquidation would have created problems which it would have been absolutely impossible to solve, and only a dreamer could have issued such a visionary statement." Islam's reforms stipulating the conditions of enslavement seriously limited the supply of new slaves. Murray Gordon does note: "Muhammad took pains in urging the faithful to free their slaves as a way of expiating their sins. Some Muslim scholars have taken this mean that his true motive was to bring about a gradual elimination of slavery. An alternative argument is that by lending the moral authority of Islam to slavery, Muhammad assured its legitimacy. Thus, in lightening the fetter, he riveted it ever more firmly in place." In the early days of Islam, a plentiful supply of new slaves were brought due to rapid conquest and expansion. But as the frontiers were gradually stabilized, this supply dwindled to a mere trickle. The prisoners of later wars between Muslims and Christians were commonly ransomed or exchanged.

According to Lewis, this reduction resulted in Arabs who wanted slaves having to look elsewhere to avoid the restrictions in the Qur'an, meaning an increase of importing of slaves from non-Muslim lands, primarily from Africa. These slaves suffered a high death toll. Patrick Manning states that Islamic legislations against the abuse of the slaves convincingly limited the extent of enslavement in Arabian Peninsula and to a lesser degree for the whole area of the whole Umayyad Caliphate where slavery had existed since the most ancient times. He however notes that with the passage of time and the extension of Islam, Islam by recognizing and codifying slavery seems to have done more to protect and expand slavery than the reverse.

In theory free-born Muslims could not be enslaved, and the only way that a non-Muslim could be enslaved was being captured in the course of holy war. (In early Islam, neither a Muslim nor a Christian or Jew could be enslaved.) Slavery was also perceived as a means of converting non-Muslims to Islam: A task of the masters was religious instruction. Conversion and assimilation into the society of the master didn't automatically lead to emancipation, though there was normally some guarantee of better treatment and was deemed a prerequisite for emancipation. The majority of Sunni authorities approved the manumission of all the "People of the Book". According to some jurists -especially among the Shi'a- only Muslim slaves should be liberated. In practice, traditional propagators of Islam in Africa often revealed a cautious attitude towards proselytizing because of its effect in reducing the potential reservoir of slaves.
Rights and restrictions
"Morally as well as physically the slave is regarded in law as an inferior being," Levy writes. Under Islamic law, a slave possesses a composite quality of being both a person and a possession. The slave is entitled to receive sustenance from the master, which includes shelter, food, clothing, and medical attention. It is a requirement for this sustenance to be of the same standard generally found in the locality and it is also recommended for the slave to have the same standard of food and clothing as the master. If the master refuses to provide the required sustenance, the slave may complain to a judge, who may then penalize the master through sale of her or his goods as necessary for the slave's keep. If the master does not have sufficient wealth to facilitate this, she or he must either sell, hire out, or manumit the slave as ordered. Slaves also have the right to a period of rest during the hottest parts of the day during the summer.

Evidence from slaves is rarely viable in a court of law. As slaves are regarded as inferior in Islamic law, death at the hands of a free man does not require that the latter be killed in retaliation. The killer must pay the slave's master compensation equivalent to the slave's value, as opposed to blood-money. At the same time, slaves themselves possess a lessened responsibility for their actions, and receive half the penalty required upon a free man. For example: where a free man would be subject to a hundred lashes due to pre-marital relations, a slave would be subject to only fifty. Slaves are allowed to marry only with the owner's consent. Jurists differ over how many wives a slave may possess, with the Hanafi and Shafi'i schools allowing them two, and the Maliki school allowing four. Slaves are not permitted to possess or inherit property, or conduct independent business, and may conduct financial dealings only as a representative of the master. Offices of authority are generally not permitted for slaves, though a slave may act as the leader (Imam) in the congregational prayers, and he may also act as a subordinate officer in the governmental department of revenue. Masters may sell, bequeath, give away, pledge, hire out or compel them to earn money.

By the view of some madh'hab (but not others), a master may compel his/her slave(s) to marriage and determine the identity of their marriage partner(s).

The mahr that is given for marriage to a female slave is taken by her owner, whereas all other women possess it absolutely for themselves.

Manumission

The Qur'an and Hadith, the primary Islamic texts, make it a praiseworthy act for masters to set their slaves free. There are numerous ways in which a slave may become free. One way is through expiation for certain sins committed by the master, such as involuntary manslaughter or perjury. Other ways include emancipation through becoming an umm walad, who is freed upon her master's death along with her children, or an independent act of piety by the master, as recommended by the Quran. It is also commendable to manumit a slave who demands his freedom and is considered worthy of it; however, Richard Francis Burton states in a footnote to the "Tale of the Second Eunuch", commenting on the proposed emancipation of a slave without employable skills, that "Here the slave refuses to be set free and starve. For a master so to do without ample reasons is held disgraceful. I well remember the weeping and wailing throughout Sind when an order from Sir Charles Napier set free the negroes whom British philanthropy thus doomed to endure if not to die of hunger." Another method is the mukataba contract: Levy states that "the slave may redeem himself if his master agrees and contracts to let him go on payment of a stipulated sum of money, which may be paid in two or more instalments, or on the giving of stipulated services or other consideration. If the consideration is a sum of money, the master must grant the slave the right to earn and to own property."

If the master makes a declaration of the slave's freedom, whether in jest or earnest, in the presence of the slave or another, then such a declaration becomes legally binding. Similarly, the master may promise manumission (verbally or in writing) that the slave is to be freed upon the former's death. Lastly, a slave is also freed automatically if she or he comes into the possession of a master who is directly related to her or him.

Gordon opines that the Quran in particular and Islamic jurisprudence in general have not placed a premium on manumission but held it out as one way for atonement of sin. He states that "Manumission was only one of several virtuous observances that the pious could avail themselves of and was by no means the most important," noting that other options include reaffirming faith in God and giving food to the poor. He concludes that "there was no contradiction between being a devout Muslim and a slave-owing one as well."

Modern interpretations

Abolitionism

A photograph of a slave boy in the Sultanate of Zanzibar. 'An Arab master's punishment for a slight offence.' c. 1890. From at least the 1860s onwards, photography was a powerful weapon in the abolitionist arsenal.
 
The abolition movement starting in the 19th century in England and later in other Western countries influenced the slavery in Muslim lands both in doctrine and in practice. One of the first religious decrees comes from the two highest dignitaries of the Hanafi and Maliki rites in the Ottoman Empire. These religious authorities declared that slavery is lawful in principle but it is regrettable in its consequences. They expressed two religious considerations in their support for abolition of slavery: "the initial enslaving of the people concerned comes under suspicion of illegality by reason of the present-day expansion of Islam in their countries; masters no longer comply with the rules of good treatment which regulate their rights and shelter them from wrong-doing."

According to Brunschvig, although the total abolition of slavery might seem a reprehensible innovation and contrary to the Qur'an and the practice of early Muslims, the realities of the modern world caused a "discernible evolution in the thought of many educated Muslims before the end of the 19th century." These Muslims argued that Islam on the whole has "bestowed an exceptionally favourable lot on the victims of slavery" and that the institution of slavery is linked to the particular economic and social stage in which Islam originated. According to the influential thesis of Ameer Ali, Islam only tolerated slavery through temporary necessity and that its complete abolition was not possible at the time of Muhammad. By the early 20th century, the idea that Islam only tolerated slavery due to necessity was to varying extent taken up by the Ulema. However, it was unable to gain support among the Wahhabis as of 1980s.

According to Brockopp, in the Ottoman empire and elsewhere the manumission contract (kitaba) was used by the state to give slaves the means to buy their freedom and thereby end slavery as an institution. Some authorities issued condemnations of slavery, stating that it violated Quranic ideals of equality and freedom. Subsequently, even religious conservatives came to accept that slavery was contrary to Islamic principles of justice and equality.

Islamist opinions

Earlier in the 20th century, prior to the "reopening" of slavery by Salafi scholars like Shaykh al-Fawzan, Islamist authors declared slavery outdated without actually clearly affirming and promoting its abolition. This has caused at least one scholar (William Clarence-Smith) to bemoan the "dogged refusal of Mawlana Mawdudi to give up on slavery" and the notable "evasions and silences of Muhammad Qutb".

Sayyid Qutb, the scholar of the Islamist Muslim Brotherhood said in his exegesis (Tafsir) of the Quran:
And concerning slavery, that was when slavery was a world-wide structure and which was conducted amongst Muslims and their enemies in the form of enslaving of prisoners of war. And it was necessary for Islam to adopt a similar line of practise until the world devised a new code of practise during war other than enslavement.
Qutb's brother Muhammad Qutb contrasted sexual relations between Muslim slave-owners and their female slaves with (in his view), the widespread and depraved practice of casual consensual sex in contemporary Europe:
Islam made it lawful for a master to have a number of slave-women captured in wars and enjoined that he alone may have sexual relations with them ... Europe abhors this law but at the same gladly allows that most odious form of animalism according to which a man may have illicit relations with any girl coming across him on his way to gratify his animal passions.
Islam has clearly and categorically forbidden the primitive practice of capturing a free man, to make him a slave or to sell him into slavery. On this point the clear and unequivocal words of Muhammad are as follows:
"There are three categories of people against whom I shall myself be a plaintiff on the Day of Judgement. Of these three, one is he who enslaves a free man, then sells him and eats this money" (al-Bukhari and Ibn Majjah).
The words of this Tradition of the Prophet are also general, they have not been qualified or made applicable to a particular nation, race, country or followers of a particular religion. ... After this the only form of slavery which was left in Islamic society was the prisoners of war, who were captured on the battlefield. These prisoners of war were retained by the Muslim Government until their government agreed to receive them back in exchange for Muslim soldiers captured by them ...

Taqiuddin al-Nabhani, a shariah judge and founder of Hizb ut-Tahrir movement, gives the following explanation:
When Islam came, for the situations where people were taken into slavery (e.g. debt), Islam imposed Shari’ah solutions to those situations other than slavery. ... It (Islam) made the existing slave and owner form a business contract, based upon the freedom, not upon slavery ... As for the situation of war, ... it clarified the rule of the captive in that either they are favoured by releasing without any exchange, or they are ransomed for money or exchanged for Muslims or non-Muslim citizens of the Caliphate.
The website of the organization stresses that because sharia historically was responding to a contract, not the institution of slavery, a future Khilafah could not re-introduce slavery.

While prominent clerics of Twelver Shia Islam have joined in declarations against contemporary slavery, at least one powerful Shi'a Islamist ayatollah (Mohammad-Taqi Mesbah-Yazdi, a member of Iran's Assembly of Experts, the body responsible for choosing the Supreme Leader of Iran) has made several statements declaring the permissibility of slavery in modern times. In a 2006 interview he stated,
Today, too, if there's a war between us and the infidels, we'll take slaves. The ruling on slavery hasn't expired and is eternal. We'll take slaves and we'll bring them to the world of Islam and have them stay with Muslims. We'll guide them, make them Muslims and then return them to their countries.
In response to the Nigerian extremist group Boko Haram's Quranic justification for kidnapping and enslaving people, and ISIL's religious justification for enslaving Yazidi women as spoils of war as claimed in their digital magazine Dabiq, the 126 Islamic scholars from around the Muslim world, in late September 2014, signed an open letter to the Islamic State's leader Abu Bakr al-Baghdadi, rejecting his group's interpretations of the Qur'an and hadith to justify its actions. The letter accuses the group of instigating fitna – sedition – by instituting slavery under its rule in contravention of the anti-slavery consensus of the Islamic scholarly community.

Salafi support for slavery

In recent years, according to some scholars, there has been a "reopening" of the issue of slavery by some conservative Salafi Islamic scholars after its "closing" earlier in the 20th century when Muslim countries banned slavery and "most Muslim scholars" found the practice "inconsistent with Qur'anic morality."

A controversial high-level Saudi jurist, Shaykh Saleh Al-Fawzan, said in a lecture, "Slavery is a part of Islam. Slavery is part of jihad, and jihad will remain as long there is Islam." He further dismissed Muslim writers who maintained otherwise as ignorant and "blind followers". At the time of the fatwa, al-Fawzan was a member of the Senior Council of Clerics, Saudi Arabia's highest religious body, a member of the Council of Religious Edicts and Research, the Imam of Prince Mitaeb Mosque in Riyadh, and a professor at Imam Mohamed Bin Saud Islamic University, the main Wahhabi center of learning in the country. Another prominent Saudi cleric, Saad Al-Buraik has urged Palestinians to enslave women of "the Jews".

The Bible and slavery

From Wikipedia, the free encyclopedia

11th-century manuscript of the Hebrew Bible with Targum, Exodus 12:25-31
 
Frank's casket is an 8th-century whale bone casket, the back of which depicts the enslavement of the Jewish people
 
The Biblical texts outline sources and legal status of slaves, economic roles of slavery, types of slavery, and debt slavery, which thoroughly explain the institution of slavery in Israel in antiquity. Each section – Exodus 21, Deuteronomy 15, and Leviticus 25 – provides an outlook into the understanding of recent slave relations and gives guidance to the Israelites on how to further their life in a proper manual. Philo, one of the philosophers of the time, wrote texts on how to properly treat slaves, indicating that slavery was an important part of Jewish life, but also emphasizes the humanitarian perspective offered up by many Ancient Near East scholars. One such way of showing this was through the sharing of products, such as food and cloth, with other, underprivileged members of society.

The Bible contains several references to slavery, which was a common practice in antiquity. The Bible stipulates the treatment of slaves, especially in the Old Testament. There are also references to slavery in the New Testament. Male Israelite slaves were to be offered release after six to seven years of service. If a slave had a wife when he became enslaved,the wife and children would go with him. However, if the master has given him a wife, the wife and any children remain the property of the master indefinitely. In that case the slave could choose his family over his freedom and remain a slave for the rest of his life. Female Israelite slaves remained enslaved for their entire lives except in cases where the masters took them as wives. If a master lost interest in his wife, she was released. A foreign slave could be bequeathed to the owner's family, and was made to serve for life except in the case of certain injuries. Many of the patriarchs portrayed in the Bible were owners of slaves from the upper echelons of society and enslaved those in debt to them, bought their fellow citizen’s daughters as concubines, and perpetually enslaved foreign men to work on their fields. Masters were men, and it is not evident that women were able to own slaves until the Elephantine papyri in the 400s BC. Also, there is little historic evidence that people from all levels of society were able to own slaves. During certain reigns, especially those of Solomon and David, statewide slavery may have been instituted for large building projects or work that was deemed intolerable for free men to do. Other than these instances, it is unclear whether or not state instituted slavery was an accepted practice. It was necessary for those who owned slaves, especially in large numbers, to be wealthy because the masters had to pay taxes for Jewish and non-Jewish slaves because they were considered part of the family unit. The slaves were seen as an important part of the family’s reputation, especially in Hellenistic and Roman times where the slave companions for a woman were seen as a manifestation and protection of a woman’s honor. As time progressed, domestic slavery became more prominent, and domestic slaves, usually working as an assistant to the wife of the patriarch, allowed larger houses to run more smoothly and efficiently.

In the 19th century, both abolitionists and defenders of slavery often invoked the Bible in defense of their positions. Abolitionists used texts from both the Old and New Testaments to argue for the manumission of slaves, and against kidnapping or "stealing men" to own or sell them as slaves.

The rabbis are rarely described as having many slaves, but in documents in which they write about slaves, it is always from the master’s point of view, which is seen by scholars as an attempt to distinguish the middle class citizens from slaves who could possibly have held higher positions in society because they were owned by a wealthy man. However, owning many slaves was regular among priests in the First Temple days. This was an especially common practice in Greek religion which was supported by references to high priestly slaves in Josephus’ works. These works painted the priests in a negative light, and showed the end of the institution coming after the Second Temple days in 70 AD.

Old Testament

Slaves had a variety of different purposes. To determine the function, many scholars look at repetitive descriptions in texts that were written around the same time and reports of other cultures from the well-documented Graeco-Roman culture. One of slaves’ main functions was as status symbols for the upper members of society, especially when it came to dowries for their daughters. These slaves could be sold or given away as needed, but also showed that the family was capable of providing generous amounts for their daughters to be married off. They also catered to the needs of the temple and had more domestic abilities such as keeping up the household and raising farm animals and small amounts of crops. Masters often took advantage of their slaves being at their beck and call by requiring them to perform duties in public that the master had the ability to do himself. This showed a level of luxury which extended beyond the private sphere into the public. In addition to showing luxury, possession of slaves was necessary for a good family background, and many wealthy men viewed their colleagues who possessed only few slaves as the type of individual who needed to be pitied.

Enslavement

In the Ancient Near East, captives obtained through warfare were often compelled to become slaves, and this was seen by the Deuteronomic Code as a legitimate form of enslavement, as long as Israelites were not among the victims; the Deuteronomic Code institutes the death penalty for the crime of kidnapping Israelite men to enslave them. Deuteronomy 24:7 If the soldier desired to marry a captured foreigner, there were stipulations. She would shave her head and wear no jewelry or cosmetics to mourn the friends and family whom were killed in the war. While the term may be different depending on how many were lost, it would be for a minimum of one month. After the grieving was over, then he was free to make wedding plans. If he wished to end the relationship, the code stipulated he must free her. Because he forced her by the point of the sword or tip of the spear into a sexual relationship, he forfeited the option to sell her into slavery. The Israelites did not generally get involved in distant or large-scale wars, and apparently capture was not a significant source of slaves.

The Holiness code of Leviticus explicitly allows participation in the slave trade, with non-Israelite residents who had been sold into slavery being regarded as a type of property that could be inherited. Foreign residents were included in this permission, and were allowed to own Israelite slaves.

It was also possible to be born into slavery. If a male Israelite slave had been given a wife by his owner, then the wife and any children which had resulted from the union would remain the property of his former owner, according to the Covenant Code. Although no nationality is specified, 18th century theologians John Gill (1697–1771) and Adam Clarke suggested this referred only to Canaanite concubines.

Debt slavery

Like the rest of the Ancient Near East, the legal systems of the Israelites divided slaves into different categories: "In determining who should benefit from their intervention, the legal systems drew two important distinctions: between debt and chattel slaves, and between native and foreign slaves. The authorities intervened first and foremost to protect the former category of each--citizens who had fallen on hard times and had been forced into slavery by debt or famine."

Poverty, and more generally a lack of economic security, compelled some people to enter debt bondage. In the ancient Near East, wives and (non-adult) children were dependents of the head of household and were sometimes sold into slavery by the husband or father for financial reasons. Evidence of this viewpoint is found in the Code of Hammurabi, which permits debtors to sell their wives and children into temporary slavery, lasting a maximum of three years. The Holiness code also exhibits this, allowing foreign residents to sell their own children and families to Israelites, although no limitation is placed on the duration of such slavery. Biblical authors repeatedly criticize debt slavery, which could be attributed to high taxation, monopoly of resources, high-interest loans, and collapse of higher kinship groups.

Debt slaves were one of the two categories of slaves in Ancient Jewish society. As the name implies, these individuals sold themselves into slavery in order to pay off debts they may have accrued. These individuals were not permanently in this situation and were usually released after six to seven years. Chattel slaves, on the other hand, were less common and were usually prisoners of war who retained no individual right of redemption. These chattel slaves engaged in full-time menial labor, often in a domestic capacity.

The earlier Covenant Code instructs that, if a thief is caught after sunrise and is unable to make restitution for the theft, then the thief should be enslaved. Children of a deceased debtor may be forced into slavery to pay off outstanding debts. Similarly, it is evident that debtors could be forced to sell their children into slavery to pay the creditors.

Sexual and conjugal slavery

There were two words used for female slaves, which were amah and shifhah. Based upon the uses in different texts, the words appear to have the same connotations and are used synonymously, namely that of being a sexual object, though the words themselves appear to be from different ethnic origins. Men assigned their female slaves the same level of dependence as they would a wife. Close levels of relationships could occur given the amount of dependence placed upon these women. These slaves had two specific roles: a sexual use and companionship. Their reproductive capacities were valued within their roles within the family. Marriage with these slaves was not unheard of or prohibited. In fact, it was a man’s concubine that was seen as the “other” and shunned from the family structure. These female slaves were treated more like women than slaves which may have resulted, according to some scholars, due to their sexual role, which was particularly to “breed” more slaves. A father could sell his daughter into this life and she could be released within six years if she was not claimed by or assigned to another man. 

Sexual slavery, or being sold to be a wife, was common in the ancient world. Throughout the Old Testament, the taking of multiple wives is recorded many times. An Israelite father could sell his unmarried daughters into servitude, with the expectation or understanding that the master or his son could eventually marry her (as in Exodus 21:7-11.) It is understood by Jewish and Christian commentators that this referred to the sale of a daughter, who "is not arrived to the age of twelve years and a day, and this through poverty."
And if a man sells his daughter to be a female slave, she shall not go out as the male slaves do. If she does not please her master, who has betrothed her to himself, then he shall let her be redeemed. He shall have no right to sell her to a foreign people, since he has dealt deceitfully with her. And if he has betrothed her to his son, he shall deal with her according to the custom of daughters. If he takes another wife, he shall not diminish her food, her clothing, and her marriage rights. And if he does not do these three for her, then she shall go out free, without paying money.
— Exodus 21
The code also instructs that the woman was to be allowed to be redeemed if the man broke his betrothal to her. If a female slave was betrothed to the master's son, then she had to be treated as a normal daughter. If he took another wife, then he was required to continue supplying the same amounts of food, clothing, and conjugal rights to her. The code states that failure to comply with these regulations would automatically grant free manumission to the enslaved woman, while all Israelite slaves were to be treated as hired servants.

The betrothal clause seems to have provided an exception to the law of release in Deuteronomy 15:12 (cf. Jeremiah 34:14), in which both male and female Israelite servants were to be given release in the seventh year.

The penalty if an Israelite engaged in sexual activity with an unredeemed female slave who was betrothed was that of scourging, with Jewish tradition seeing this as only referring to the slave, (versus Deuteronomy 22:22, where both parties were stoned, being free persons), as well as the man confessing his guilt and the priest making atonement for his sin.

Women captured by Israelite armies could be adopted as wives, but first they had to have their heads shaved and undergo a period of mourning. (Deuteronomy 21:10-14) However, "If you are not pleased with her, then you must let her go where she pleases. You cannot in any case sell her; you must not take advantage of her, since you have already humiliated her."

Manumission

In a parallel with the shmita system the Covenant Code offers automatic manumission of male Israelite slaves after they have worked for six years; this excludes non-Israelite slaves, and specifically excludes Israelite daughters, who were sold into slavery by their fathers, from such automatic seventh-year manumission. Such were bought to be betrothed to the owner, or his son, and if that had not been done, they were to be allowed to be redeemed. If the marriage took place, they were to be set free if her husband was negligent in his basic marital obligations. The later Deuteronomic Code is seen by some to contradict elements of this instruction, in extending automatic seventh year manumission to both sexes. Others see the latter as a general decree, with the aspect of female manumission not being applicable within the specific circumstances of the former case, with marriage taking the place of manumission.

The Deuteronomic Code also extends the seventh-year manumission rule by instructing that Israelite slaves freed in this way should be given livestock, grain, and wine, as a parting gift; the literal meaning of the verb used, at this point in the text, for giving this gift seems to be hang round the neck. In Jewish tradition, the identified gifts were regarded as merely symbolic, representing a gift of produce rather than of money or clothing; many Jewish scholars estimated that the value of the three listed products was about 30 shekels, so the gift gradually came to be standardised as produce worth this fixed value. The Bible states that one should not regret the gift, for slaves were only half as expensive as hired workers; Nachmanides enumerates this as a command rather than merely as a piece of advice.

Despite these commandments, Israelite slaves were kept longer than permitted, compelling Yahweh to destroy the Kingdom of Judah as punishment. The text also describes Jeremiah demanding that Zedekiah manumit all Israelite slaves. The Holiness Code does not mention seventh-year manumission; instead it only instructs that debt-slaves, and Israelite slaves owned by foreign residents, should be freed during the national Jubilee (occurring either every 49 or every 50 years, depending on interpretation). 

While many commentators see the Holiness Code regulations as supplementing the prior legislation mandating manumission in the seventh year, the otherwise potentially long wait until the Jubilee was somewhat alleviated by the Holiness Code, with the instruction that slaves should be allowed to buy their freedom by paying an amount equal to the total wages of a hired servant over the entire period remaining until the next Jubilee (this could be up to 49 years-worth of wages; in 2017, this would roughly equate with £922,500 sterling). Blood relatives of the slave were also allowed to buy the slave's freedom, and this became regarded as a duty to be carried out by the next of kin (Hebrew: Go'el).

Permanent enslavement

As for Israelite slaves, the Covenant Code allows them to voluntarily renounce their seventh-year manumission and become permanent slaves (literally being slaves forever). The Covenant Code rules require that the slaves confirmed this desire at either a religious sanctuary, or in the presence of the household gods (the Masoretic Text and Septuagint both literally say [at] the gods, although a few English translations substitute in the presence of Judges); having done this, slaves were then to have an awl driven through their ear into a doorpost by their master. This ritual was common throughout the Ancient Near East, being practiced by Mesopotamians, Lydians, and Arabs; in the Semitic world, the ear symbolised obedience (much as the heart symbolises emotion, in the modern western world), and a pierced earlobe signified servitude.

Working conditions

The Ethical Decalogue makes clear that honouring the Shabbat was expected of slaves, not just their masters. The later Deuteronomic code, having repeated the Shabbat requirement, also instructs that slaves should be allowed to celebrate the Sukkot festival.

Although the Holiness Code instructs that during the Sabbatical Year, slaves and their masters should eat food which the land yields, without being farmed, it does not explicitly forbid the slaves from the farming itself, despite restricting their masters from doing so, and neither does it grant slaves any other additional rest from work during these years.

Indeed, unlike the other law codes, the Holiness Code does not mention explicit occasions of respite from toil, instead simply giving the vague instruction that Israelite slaves should not to be compelled to work with rigour; Maimonides argues that this was to be interpreted as forbidding open-ended work (such as keep doing that until I come back), and that disciplinary action was not to include instructing the slave to perform otherwise pointless work.

A special case is that of the debtor who sells himself as a slave to his creditor; the Holiness Code instructs that in this situation, the debtor must not be made to do the work of slaves, but must instead be treated the same as a hired servant. In Jewish tradition, this was taken to mean that the debtor should not be instructed to do humiliating work - which only slaves would do - and that the debtor should be asked to perform the craft(s) which they usually did before they had been enslaved, if it is realistic to do so.

Injury and compensation

The earlier Covenant Code provides a potentially more valuable and direct form of relief, namely a degree of protection for the slave's person (their body and its health) itself. This codification extends the basic lex talionis (....eye for an eye, tooth for a tooth...), to compel that when slaves are significantly injured by their masters, manumission is to be the compensation given; the canonical examples mentioned are the knocking out of an eye or a tooth. This resembles the earlier Code of Hammurabi, which instructs that when an injury is done to a social inferior, monetary compensation should be made, instead of carrying out the basic lex talionis; Josephus indicates that by his time it was acceptable for a fine to be paid to the slave, instead of manumitting them, if the slave agreed. Nachmanides argued that it was a biblically commanded duty to liberate a slave who had been harmed in this way.

The Hittite laws and the Code of Hammurabi both insist that if a slave is harmed by a 3rd party, the 3rd party must financially compensate the owner. In the Covenant Code, if an ox gores a slave, the ox owner must pay the servant's master a 30 shekel fine.

The murder of slaves by owners was prohibited in the Law covenant. The Covenant Code clearly institutes the death penalty for beating a free man to death; in contrast, beating a slave to death was to be avenged only if the slave does not survive for one or two days after the beating. Abraham ben Nathan of Lunel, a 12th-century Provençal scholar, Targum, and Maimonides argue that avenged implies the death penalty, but more recent scholars view it as probably describing a lesser punishment. A number of modern Protestant Bible versions (such as the New Living Translation, New International Version and New Century Version) translate the survival for one or two days as referring to a full and speedy recovery, rather than to a lingering death, as favoured by other recent versions (such as the New Revised Standard Version, and New American Bible).

Fugitive slaves

The Deuteronomic Code forbids the people of Israel from handing over fugitive slaves to their masters or oppressing them, and instructs that these fugitives should be allowed to reside where they wish. Although a literal reading would indicate that this applies to slaves of all nationalities and locations, the Mishnah and many commentators consider the rule to have the much narrower application, to just those slaves who flee from outside Israelite territory into it.

New Testament

Slavery is mentioned numerous times in the New Testament. The word "servant" is sometimes substituted incorrectly for the word "slave" in English translations of the Bible.

Gospels

Jesus healed the ill slave of a centurion and restored the cut off ear of the high priest's slave. In his parables, Jesus referenced slavery: the prodigal son, ten gold coins, unforgiving tenant, and tenant farmers. Jesus' teaching on slavery was metaphorical: spiritual slavery, a slave having two masters (God and mammon), slavery to God, acting as a slave toward others, and the greatest among his disciples being the least of them. Jesus also taught that he would give burdened and weary laborers rest. The Passion narratives are interpreted by the Catholic church as a fulfillment of the Suffering Servant songs in Isaiah.

Jesus’ view of slavery compares the relationship between god and humankind to that of a master and his slaves. Three instances where Jesus communicates this view include:

Matthew 18:21-35: Jesus’ “Parable of the Unmerciful Servant”, wherein Jesus compares the relationship between god and humankind to that of a master and his slaves. Jesus offers the story of a master selling a slave along with his wife and children. 

Matthew 20:20-28: A series of remarks wherein Jesus recognizes it is necessary to be a slave to be “first” among the deceased entering heaven.

Matthew 24:36-51: Jesus’ “Parable of the Faithful Servant”, wherein Jesus again compares the relationship between God and humankind to that of a master and his slaves.

Epistles

In Eph 6:5-8, Col 3:22-24, 1Tim 6:1-2 and Titus 2:9-10 Saint Paul instruct slaves to obey their masters. In 1Pet 2:18 Saint Peter also instructs slaves to obey their masters. In Col 4:1 Paul instructs masters to "treat your slaves justly and fairly." In Romans 1:1 Paul metaphorically calls himself a "slave of Christ Jesus," and in Romans 6:20-21 he writes about the metaphor of slavery to sin. In Gal 3:27-29 Paul says that in the church there is "neither slave nor free person,...for you are all one in Christ Jesus." In Revelation, two angels call themselves fellow slaves (coworkers) of Saint John.

Philemon

The Epistle to Philemon has become an important text in regard to slavery; it was used by pro-slavery advocates as well as by abolitionists. In the epistle, Saint Paul writes to Saint Philemon that he is returning Saint Onesimus, a fugitive slave, back to him; however, Paul also entreats Philemon to regard Onesimus, who he says he views as a son, not as a slave but as a beloved brother in Christ. Philemon is requested to treat Onesimus as he would treat Paul. According to Catholic tradition, Philemon freed Onesimus.

Wednesday, May 1, 2019

Gas chromatography–mass spectrometry

From Wikipedia, the free encyclopedia

Example of a GC-MS instrument
 
Gas chromatography–mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. Applications of GC-MS include drug detection, fire investigation, environmental analysis, explosives investigation, and identification of unknown samples, including that of material samples obtained from planet Mars during probe missions as early as the 1970s. GC-MS can also be used in airport security to detect substances in luggage or on human beings. Additionally, it can identify trace elements in materials that were previously thought to have disintegrated beyond identification. Like liquid chromatography–mass spectrometry, it allows analysis and detection even of tiny amounts of a substance.

GC-MS has been regarded as a "gold standard" for forensic substance identification because it is used to perform a 100% specific test, which positively identifies the presence of a particular substance. A nonspecific test merely indicates that any of several in a category of substances is present. Although a nonspecific test could statistically suggest the identity of the substance, this could lead to false positive identification.

History

The first on-line coupling of gas chromatography to a mass spectrometer was reported in 1959. The development of affordable and miniaturized computers has helped in the simplification of the use of this instrument, as well as allowed great improvements in the amount of time it takes to analyze a sample. In 1964, Electronic Associates, Inc. (EAI), a leading U.S. supplier of analog computers, began development of a computer controlled quadrupole mass spectrometer under the direction of Robert E. Finnigan. By 1966 Finnigan and collaborator Mike Uthe's EAI division had sold over 500 quadrupole residual gas-analyzer instruments. In 1967, Finnigan left EAI to form the Finnigan Instrument Corporation along with Roger Sant, T. Z. Chou, Michael Story, and William Fies. In early 1968, they delivered the first prototype quadrupole GC/MS instruments to Stanford and Purdue University. When Finnigan Instrument Corporation was acquired by Thermo Instrument Systems (later Thermo Fisher Scientific) in 1990, it was considered "the world's leading manufacturer of mass spectrometers".

Instrumentation

The insides of the GC-MS, with the column of the gas chromatograph in the oven on the right.
 
The GC-MS is composed of two major building blocks: the gas chromatograph and the mass spectrometer. The gas chromatograph utilizes a capillary column which depends on the column's dimensions (length, diameter, film thickness) as well as the phase properties (e.g. 5% phenyl polysiloxane). The difference in the chemical properties between different molecules in a mixture and their relative affinity for the stationary phase of the column will promote separation of the molecules as the sample travels the length of the column. The molecules are retained by the column and then elute (come off) from the column at different times (called the retention time), and this allows the mass spectrometer downstream to capture, ionize, accelerate, deflect, and detect the ionized molecules separately. The mass spectrometer does this by breaking each molecule into ionized fragments and detecting these fragments using their mass-to-charge ratio.

GC-MS schematic
 
These two components, used together, allow a much finer degree of substance identification than either unit used separately. It is not possible to make an accurate identification of a particular molecule by gas chromatography or mass spectrometry alone. The mass spectrometry process normally requires a very pure sample while gas chromatography using a traditional detector (e.g. Flame ionization detector) cannot differentiate between multiple molecules that happen to take the same amount of time to travel through the column (i.e. have the same retention time), which results in two or more molecules that co-elute. Sometimes two different molecules can also have a similar pattern of ionized fragments in a mass spectrometer (mass spectrum). Combining the two processes reduces the possibility of error, as it is extremely unlikely that two different molecules will behave in the same way in both a gas chromatograph and a mass spectrometer. Therefore, when an identifying mass spectrum appears at a characteristic retention time in a GC-MS analysis, it typically increases certainty that the analyte of interest is in the sample.

Purge and trap GC-MS

For the analysis of volatile compounds, a purge and trap (P&T) concentrator system may be used to introduce samples. The target analytes are extracted by mixing the sample with water and purge with inert gas (e.g. Nitrogen gas) into an airtight chamber, this is known as purging or sparging. The volatile compounds move into the headspace above the water and are drawn along a pressure gradient (caused by the introduction of the purge gas) out of the chamber. The volatile compounds are drawn along a heated line onto a 'trap'. The trap is a column of adsorbent material at ambient temperature that holds the compounds by returning them to the liquid phase. The trap is then heated and the sample compounds are introduced to the GC-MS column via a volatiles interface, which is a split inlet system. P&T GC-MS is particularly suited to volatile organic compounds (VOCs) and BTEX compounds (aromatic compounds associated with petroleum).

A faster alternative is the "purge-closed loop" system. In this system the inert gas is bubbled through the water until the concentrations of organic compounds in the vapor phase are at equilibrium with concentrations in the aqueous phase. The gas phase is then analysed directly.

Types of mass spectrometer detectors

The most common type of mass spectrometer (MS) associated with a gas chromatograph (GC) is the quadrupole mass spectrometer, sometimes referred to by the Hewlett-Packard (now Agilent) trade name "Mass Selective Detector" (MSD). Another relatively common detector is the ion trap mass spectrometer. Additionally one may find a magnetic sector mass spectrometer, however these particular instruments are expensive and bulky and not typically found in high-throughput service laboratories. Other detectors may be encountered such as time of flight (TOF), tandem quadrupoles (MS-MS) (see below), or in the case of an ion trap MSn where n indicates the number mass spectrometry stages.

GC-tandem MS

When a second phase of mass fragmentation is added, for example using a second quadrupole in a quadrupole instrument, it is called tandem MS (MS/MS). MS/MS can sometimes be used to quantitate low levels of target compounds in the presence of a high sample matrix background.

The first quadrupole (Q1) is connected with a collision cell (Q2) and another quadrupole (Q3). Both quadrupoles can be used in scanning or static mode, depending on the type of MS/MS analysis being performed. Types of analysis include product ion scan, precursor ion scan, selected reaction monitoring (SRM) (sometimes referred to as multiple reaction monitoring (MRM)) and neutral loss scan. For example: When Q1 is in static mode (looking at one mass only as in SIM), and Q3 is in scanning mode, one obtains a so-called product ion spectrum (also called "daughter spectrum"). From this spectrum, one can select a prominent product ion which can be the product ion for the chosen precursor ion. The pair is called a "transition" and forms the basis for SRM. SRM is highly specific and virtually eliminates matrix background.

Ionization

After the molecules travel the length of the column, pass through the transfer line and enter into the mass spectrometer they are ionized by various methods with typically only one method being used at any given time. Once the sample is fragmented it will then be detected, usually by an electron multiplier, which essentially turns the ionized mass fragment into an electrical signal that is then detected. 

The ionization technique chosen is independent of using full scan or SIM. 

Block diagram for gas chromatography using electron ionization for collecting mass spectrum.

Electron ionization

By far the most common and perhaps standard form of ionization is electron ionization (EI). The molecules enter into the MS (the source is a quadrupole or the ion trap itself in an ion trap MS) where they are bombarded with free electrons emitted from a filament, not unlike the filament one would find in a standard light bulb. The electrons bombard the molecules, causing the molecule to fragment in a characteristic and reproducible way. This "hard ionization" technique results in the creation of more fragments of low mass-to-charge ratio (m/z) and few, if any, molecules approaching the molecular mass unit. Hard ionization is considered by mass spectrometrists as the employ of molecular electron bombardment, whereas "soft ionization" is charge by molecular collision with an introduced gas. The molecular fragmentation pattern is dependent upon the electron energy applied to the system, typically 70 eV (electron Volts). The use of 70 eV facilitates comparison of generated spectra with library spectra using manufacturer-supplied software or software developed by the National Institute of Standards (NIST-USA). Spectral library searches employ matching algorithms such as Probability Based Matching and dot-product matching that are used with methods of analysis written by many method standardization agencies. Sources of libraries include NIST, Wiley, the AAFS, and instrument manufacturers.

Cold electron ionization

The "hard ionization" process of electron ionization can be softened by the cooling of the molecules before their ionization, resulting in mass spectra that are richer in information. In this method named cold electron ionization (cold-EI) the molecules exit the GC column, mixed with added helium make up gas and expand into vacuum through a specially designed supersonic nozzle, forming a supersonic molecular beam (SMB). Collisions with the make up gas at the expanding supersonic jet reduce the internal vibrational (and rotational) energy of the analyte molecules, hence reducing the degree of fragmentation caused by the electrons during the ionization process. Cold-EI mass spectra are characterized by an abundant molecular ion while the usual fragmentation pattern is retained, thus making cold-EI mass spectra compatible with library search identification techniques. The enhanced molecular ions increase the identification probabilities of both known and unknown compounds, amplify isomer mass spectral effects and enable the use of isotope abundance analysis for the elucidation of elemental formulae.

Chemical ionization

In chemical ionization a reagent gas, typically methane or ammonia is introduced into the mass spectrometer. Depending on the technique (positive CI or negative CI) chosen, this reagent gas will interact with the electrons and analyte and cause a 'soft' ionization of the molecule of interest. A softer ionization fragments the molecule to a lower degree than the hard ionization of EI. One of the main benefits of using chemical ionization is that a mass fragment closely corresponding to the molecular weight of the analyte of interest is produced. 

In positive chemical ionization (PCI) the reagent gas interacts with the target molecule, most often with a proton exchange. This produces the species in relatively high amounts.

In negative chemical ionization (NCI) the reagent gas decreases the impact of the free electrons on the target analyte. This decreased energy typically leaves the fragment in great supply.

Analysis

A mass spectrometer is typically utilized in one of two ways: full scan or selective ion monitoring (SIM). The typical GC-MS instrument is capable of performing both functions either individually or concomitantly, depending on the setup of the particular instrument. 

The primary goal of instrument analysis is to quantify an amount of substance. This is done by comparing the relative concentrations among the atomic masses in the generated spectrum. Two kinds of analysis are possible, comparative and original. Comparative analysis essentially compares the given spectrum to a spectrum library to see if its characteristics are present for some sample in the library. This is best performed by a computer because there are a myriad of visual distortions that can take place due to variations in scale. Computers can also simultaneously correlate more data (such as the retention times identified by GC), to more accurately relate certain data. Deep learning was shown to lead to promising results in the identification of VOCs from raw GC-MS data.
 
Another method of analysis measures the peaks in relation to one another. In this method, the tallest peak is assigned 100% of the value, and the other peaks being assigned proportionate values. All values above 3% are assigned. The total mass of the unknown compound is normally indicated by the parent peak. The value of this parent peak can be used to fit with a chemical formula containing the various elements which are believed to be in the compound. The isotope pattern in the spectrum, which is unique for elements that have many natural isotopes, can also be used to identify the various elements present. Once a chemical formula has been matched to the spectrum, the molecular structure and bonding can be identified, and must be consistent with the characteristics recorded by GC-MS. Typically, this identification is done automatically by programs which come with the instrument, given a list of the elements which could be present in the sample.

A “full spectrum” analysis considers all the “peaks” within a spectrum. Conversely, selective ion monitoring (SIM) only monitors selected ions associated with a specific substance. This is done on the assumption that at a given retention time, a set of ions is characteristic of a certain compound. This is a fast and efficient analysis, especially if the analyst has previous information about a sample or is only looking for a few specific substances. When the amount of information collected about the ions in a given gas chromatographic peak decreases, the sensitivity of the analysis increases. So, SIM analysis allows for a smaller quantity of a compound to be detected and measured, but the degree of certainty about the identity of that compound is reduced.

Full scan MS

When collecting data in the full scan mode, a target range of mass fragments is determined and put into the instrument's method. An example of a typical broad range of mass fragments to monitor would be m/z 50 to m/z 400. The determination of what range to use is largely dictated by what one anticipates being in the sample while being cognizant of the solvent and other possible interferences. A MS should not be set to look for mass fragments too low or else one may detect air (found as m/z 28 due to nitrogen), carbon dioxide (m/z 44) or other possible interference. Additionally if one is to use a large scan range then sensitivity of the instrument is decreased due to performing fewer scans per second since each scan will have to detect a wide range of mass fragments.

Full scan is useful in determining unknown compounds in a sample. It provides more information than SIM when it comes to confirming or resolving compounds in a sample. During instrument method development it may be common to first analyze test solutions in full scan mode to determine the retention time and the mass fragment fingerprint before moving to a SIM instrument method.

Selective ion monitoring

In selective ion monitoring (SIM) certain ion fragments are entered into the instrument method and only those mass fragments are detected by the mass spectrometer. The advantages of SIM are that the detection limit is lower since the instrument is only looking at a small number of fragments (e.g. three fragments) during each scan. More scans can take place each second. Since only a few mass fragments of interest are being monitored, matrix interferences are typically lower. To additionally confirm the likelihood of a potentially positive result, it is relatively important to be sure that the ion ratios of the various mass fragments are comparable to a known reference standard.

Applications

Environmental monitoring and cleanup

GC-MS is becoming the tool of choice for tracking organic pollutants in the environment. The cost of GC-MS equipment has decreased significantly, and the reliability has increased at the same time, which has contributed to its increased adoption in environmental studies.

Criminal forensics

GC-MS can analyze the particles from a human body in order to help link a criminal to a crime. The analysis of fire debris using GC-MS is well established, and there is even an established American Society for Testing and Materials (ASTM) standard for fire debris analysis. GCMS/MS is especially useful here as samples often contain very complex matrices and results, used in court, need to be highly accurate.

Law enforcement

GC-MS is increasingly used for detection of illegal narcotics, and may eventually supplant drug-sniffing dogs.[1] A simple and selective GC-MS method for detecting marijuana usage was recently developed by the Robert Koch-Institute in Germany. It involves identifying an acid metabolite of tetrahyhydrocannabinol (THC), the active ingredient in marijuana, in urine samples by employing derivatization in the sample preparation. GC-MS is also commonly used in forensic toxicology to find drugs and/or poisons in biological specimens of suspects, victims, or the deceased. In drug screening, GC-MS methods frequently utilize liquid-liquid extraction as a part of sample preparation, in which target compounds are extracted from blood plasma.

Sports anti-doping analysis

GC-MS is the main tool used in sports anti-doping laboratories to test athletes' urine samples for prohibited performance-enhancing drugs, for example anabolic steroids.

Security

A post–September 11 development, explosive detection systems have become a part of all US airports. These systems run on a host of technologies, many of them based on GC-MS. There are only three manufacturers certified by the FAA to provide these systems, one of which is Thermo Detection (formerly Thermedics), which produces the EGIS, a GC-MS-based line of explosives detectors. The other two manufacturers are Barringer Technologies, now owned by Smith 's Detection Systems, and Ion Track Instruments, part of General Electric Infrastructure Security Systems.

Chemical warfare agent detection

As part of the post-September 11 drive towards increased capability in homeland security and public health preparedness, traditional GC-MS units with transmission quadrupole mass spectrometers, as well as those with cylindrical ion trap (CIT-MS) and toroidal ion trap (T-ITMS) mass spectrometers have been modified for field portability and near real-time detection of chemical warfare agents (CWA) such as sarin, soman, and VX. These complex and large GC-MS systems have been modified and configured with resistively heated low thermal mass (LTM) gas chromatographs that reduce analysis time to less than ten percent of the time required in traditional laboratory systems. Additionally, the systems are smaller, and more mobile, including units that are mounted in mobile analytical laboratories (MAL), such as those used by the United States Marine Corps Chemical and Biological Incident Response Force MAL and other similar laboratories, and systems that are hand-carried by two-person teams or individuals, much ado to the smaller mass detectors. Depending on the system, the analytes can be introduced via liquid injection, desorbed from sorbent tubes through a thermal desorption process, or with solid-phase micro extraction (SPME).

Chemical engineering

GC-MS is used for the analysis of unknown organic compound mixtures. One critical use of this technology is the use of GC-MS to determine the composition of bio-oils processed from raw biomass.

Food, beverage and perfume analysis

Foods and beverages contain numerous aromatic compounds, some naturally present in the raw materials and some forming during processing. GC-MS is extensively used for the analysis of these compounds which include esters, fatty acids, alcohols, aldehydes, terpenes etc. It is also used to detect and measure contaminants from spoilage or adulteration which may be harmful and which is often controlled by governmental agencies, for example pesticides.

Astrochemistry

Several GC-MS have left earth. Two were brought to Mars by the Viking program. Venera 11 and 12 and Pioneer Venus analysed the atmosphere of Venus with GC-MS. The Huygens probe of the Cassini–Huygens mission landed one GC-MS on Saturn's largest moon, Titan. The material in the comet 67P/Churyumov–Gerasimenko will be analysed by the Rosetta mission with a chiral GC-MS in 2014.

Medicine

Dozens of congenital metabolic diseases also known as inborn errors of metabolism (IEM) are now detectable by newborn screening tests, especially the testing using gas chromatography–mass spectrometry. GC-MS can determine compounds in urine even in minor concentration. These compounds are normally not present but appear in individuals suffering with metabolic disorders. This is increasingly becoming a common way to diagnose IEM for earlier diagnosis and institution of treatment eventually leading to a better outcome. It is now possible to test a newborn for over 100 genetic metabolic disorders by a urine test at birth based on GC-MS. 

In combination with isotopic labeling of metabolic compounds, the GC-MS is used for determining metabolic activity. Most applications are based on the use of 13C as the labeling and the measurement of 13C-12C ratios with an isotope ratio mass spectrometer (IRMS); an MS with a detector designed to measure a few select ions and return values as ratios.

Occam's razor

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Occam%27s_razor In philosophy , Occa...