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Contents Determination Using Fourier Transform Infrared Biology Essay

Clandestine laboratory analysis uses many forensic techniques in particular infrared spectroscopy to aid determination of controlled substances which may be used in clandestine production of amphetamines. Using information provided in the Misuse of Drugs Act and known controlled substance it is possible to determine the legitimacy of substance used.

Introduction

A clandestine laboratory is literally a secret room or building equipped for scientific research or manufacture (Christian 2003). The vast majority of illicit laboratories are involved in the production of amphetamine and methamphetamine. There are many other drugs, explosives and even chemical or biological warfare agents which have been produced. (Smith andSiegel 2004) The laboratories can come in a variety of different shapes and sizes depending on the sophistication and skills of the clandestine lab operator (Christian 2003). This may cause problems for a clandestine laboratory investigator to determine whether a lab is in a particular area or not. The task faced by the investigator is made harder due to many of the chemicals such as Benzaldehyde, ethyl acetate and nitroethane having legitimate uses (Christian 2004). This can mean that if these chemicals but no other chemicals such as benzyl cyanide which does not have any legitimate uses are found at a scene it may not be possible to state definitively that a clandestine lab is operating from that area.

The amphetamine family is made up of a number of compounds which are similar in structure and physiological effect to the body. The term amphetamine is an acronym for alpha-methyl-phenethylamine (Nichols, 1994). The family includes but is not exclusive to Amphetamine, Methylamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethyl-amphetamine (MDMA also known as ecstasy) and 3,4-methylenedioxyethylamphetamine (MDEA). Amphetamines are powerful central nervous system (CNS) stimulants which affect the catecholamines dopamine (DA) and norepinephrine (NE) (Smith andSiegel 2004). Amphetamines are monitored and controlled under the Misuse of Drug Act 1971 which states that amphetamine is a class B drugs and Methylamphetamine has been upgraded from a class B drug to a class A drug as of January 2007. The decision to reclassify Methylamphetamine was based on international experience and the advice of the Advisory Council on the Misuse of Drugs (ACMD) (Scottish Crime and Drug Enforcement Agency 2007).

For a clandestine laboratory they must determine what they can produce with the materials at their disposal. The main factors considered for this are availability of precursors, reagents, solvents, complexity of the process, availability of equipment, and chemical hazards (White, M 2004). As stated before many of the chemicals that can be used in clandestine labs are available for legitimate purposes therefore making it easy for the operators of the labs to collect everything that they require to produce amphetamines, heroin, cocaine and any other synthetic compound that they wish to produce. Many clandestine laboratories will stick to production of amphetamines as the chemistry involved in the production of these compounds is not as difficult as other synthetic compounds can be. Many different methods are available for production of amphetamine either from scientific literature or online. There are numerous ways of producing different members of the amphetamine family; these are dependant on the availability of different solvents, precursors and reagents. One such example for the production of amphetamine is the Leuckart synthesis reaction. The Leuckart is best described as a process for the reductive amination of aldehydes or ketones by formamide, ammonium formate or formic acid with formamide (Pollard, C.B. Young, D. 1951). There are numerous other methods which may be employed by clandestine lab operators to produce different drugs, for amphetamine alone the there are seven methods identified in Christian’s Field guide to clandestine laboratory investigation.

If an investigator believes that a clandestine lab is in operation they must follow strict safety procedures to ensure that no harm will come to them while they carry out the investigation. There are three general hazards which are present at all clandestine lab scene which must be considered before the investigation can begin. These are little to no chemical training, makeshift operations and each scene is unique (Christian 2003). Depending on the size of the clandestine operation and the product that is produced other hazards must be considered by an investigator such as explosions which may occur due to little chemical safety training or in the form of a booby trap set up by the operators of the lab to destroy the lab and to harm anyone that may attempt to enter the scene. Another hazard faced by investigators of clandestine labs is fire as with explosions fires may occur due to poor chemical knowledge of the operators or as a way to destroy the lab or injure those who would enter. Firearms will commonly be held by the operators of a clandestine lab so that they will be able to defend their lab if required to do so. It is of the utmost importance for an investigator to wear full personal protective equipment (PPE) before entering into a scene as they will not known what types of chemicals are present. Many chemicals used within a clandestine lab will cause irritation of skin (ammonium formate), eye damage (Ammonium hydroxide), Respiratory problems (Benzaldehyde) (Christian,D 2004) along with many other problems.

Once a clandestine lab has been identified the chemicals recovered from it can be analysed using a variety of techniques to determine which chemicals are present. This will in turn assist in determining which drug if any was being produced leading to prosecution under the Misuse of Drugs Act 1971. The different tests carried out on the samples of possible drugs obtained from a suspected clandestine lab will have a presumptive test carried out on them. This normally involves Marquis Reagent for suspected amphetamine samples as it will turn orange/ brown in the presence of amphetamines. This can be useful for a quick elimination of different compounds however it is not specific enough to differentiate between the members of the amphetamine family. Other reagents used for presumptive testing include Cobalt thiocyanate which is useful in identification of cocaine as it will turn blue. After a positive presumptive test has been carried out the sample is then sent to the lab for further analysis. This may involve chromatographic techniques such as thin layer chromatography (TLC) is used to assist identification and differentiation between different compounds. Following the TLC of the suspect compound the sample is then analysed using Gas chromatography with Mass Spectroscopy (GC-MS) to aid identification of the sample. In the case of the chemicals used to produce the drug Infrared spectroscopy is commonly used as a method of analysis as it will give the chemical fingerprint of the sample (Christian, D. 2003). This information along with information gathered from other sources can lead to positive identification of the compounds in question and may lead to a conviction for those found to have dealt with the compounds in question.

Results

Sample 1: Solv 3 Liquid Film

From the spectrum five peaks were identified to help determine which compound produced the spectrum. The peaks identified were:

2983 cm-1: The strong peak suggests an Alkyl C-H stretching vibration.

1743 cm-1: The strong peak suggests an Ester C=O stretching vibration.

1374 cm-1: The strong peak at suggests an Alkyl C-H bending vibration

1243 & 1048 cm-1: The strong peaks at suggests Ester =C-O-C- stretching vibration.

The information obtained regarding the key peaks on the spectrum allowed for the suggestion that the sample was an Alkyl Ester. It is not possible to determine how many Alkyl groups are present in a compound from the Infrared spectrum alone. This will mean that it is not possible to determine the structure definitively without further information.

Possible Structure

Ethyl Acetate

Sample 2: R3 Thin Film

Four peaks were identified for sample 2. These peaks are:

2992 & 2916 cm-1: These weak peaks suggest Alkyl C-H stretching vibrations.

1770 cm-1: This strong peak suggests an Ester C=O stretching vibration.

1169 cm-1: This strong peak suggests an Ester =C-O-C stretching vibration.

The information gathered from this spectrum indicates an Alkyl Ester is present. Using this information it is possible to eliminate certain compounds from the two lists of known chemicals used in clandestine labs. From the list it is possible to suggest that the compound which has produced the spectrum is gamma-butrolactone (GBL). This is because GBL contains the functional groups presented in the spectrum. It can not be stated that the compound is definitely GBL but based on the information it is a possible structure.

Possible structure

Gamma- Butyrolactone

Sample 3: A on Lid Liquid Film

Six key peaks were identified for this sample, these peaks are:

3035 cm-1: This medium peak suggests an aromatic C-H stretching vibration.

2252 cm-1: This medium peak suggests a cyanide (nitrile) C= N stretching vibration.

1498 & 1455 cm-1: These strong peaks suggest aromatic C-C ring vibration.

735 & 696 cm-1: These strong peaks suggest aromatic C-H bending vibration in a mono substituted position.

Based on the information gathered from the infrared spectrum it can be said that the compound contains an aromatic ring and a cyanide group. From the list of known chemicals used in clandestine labs it is possible to suggest the compound which has produced to spectrum is Benzyl Cyanide.

Possible Structure

Benzyl Cyanide

Sample 4: DB96 KBr disc

Six peak regions were identified and are discussed below:

3067 cm-1: A weak peak suggests aromatic C-H stretching vibration. This peak seems very weak possibly due to the presence of the impurity.

1655 cm-1: A strong peak at this region usually suggests an amide; however the lack of peaks around 3450-3200 cm-1 suggests that the compound does not contain an amide. It is also common for an amide to be attached to an alkyl group but there are no key peaks that suggest the presence of an alkyl group. There is a peak around 3067 cm-1 however an alkyl group would give a strong peak or if the impurity affected the peak it should be a medium peak. It is known that if a ketone is directly attached to an aromatic ring the region of the spectrum at which the peak should be found would travel down the range from around 1700 cm-1 to around 1650 cm-1. Based on this information it is possible to suggest that the sample contains a ketone attached directly to an aromatic ring.

1595 & 1449 cm-1: These peaks along with others around this region suggest aromatic C-C ring vibration. One peak is of medium absorption and the other is strong absorption, this difference in peak strength suggests that there may be more than one aromatic ring present. This cannot be confirmed due to the lack of further information regarding the compound.

705 & 697 cm-1: These strong peaks suggest an aromatic mono substituted C-H bending vibration.

Possible Structure

BenzophenoneAll of the functional groups indicated above can give the suggested structure of Benzophenone as this will account for the aromatic ring and the ketone. It is not definitive as more information would be required.

Sample 5: Low quality KBr

Five peaks were identified to assist identification of the unknown sample, these peaks are discussed below:

3317 cm-1: This weak peak suggests a secondary amine N-H stretching vibration is present. This is due to only one peak appearing in the region where amines are commonly located.

2966 cm-1: This medium peak suggests an alkyl C-H stretching vibration.

1488 & 1442 cm-1: These strong peaks suggest aromatic C-C ring vibration.

1249 cm-1: This strong peak suggests the presence of an ether attached to an aromatic ring as it is slightly above the normal 1240 cm-1 region.

All of the functional groups mentioned above indicate the possible structure of 3,4-methylenedioxy-N-methylamphetamine (MDMA) as this accounts for each major peak identified.

Possible structure

MDMA

Sample 6: Cork Ring Liquid Film

Three key peaks were identified and are detailed below:

2999 cm-1: This weak peak suggests an alkyl C-H stretching vibration.

1556 cm-1: This strong peak suggests an asymmetrical Nitro NO2 stretching vibration.

1396 cm-1: This medium-strong peak suggests an alkyl C-H bending vibration.

The information gathered from the spectrum suggests that a nitro group is attached to an alkyl group. There is no further information to aid determination of the number of alkyl group present. It is possible to suggest a structure for the compound based on the list provided as there is a compound which contains a nitro group and an ethyl group. This compound is Nitroethane.

Possible structure

Nitroethane

Sample 7: DB115a Liquid film

Five key peaks were used to help identify the possible structure for sample 7, these are:

2850 & 2736 cm-1: These weak peaks suggest an Aldehyde C-H stretching vibration. This is due to only aldehyde’s and Carboxylic acid groups being found in this region; however a carboxylic acid would show a broad peak between 3200-2500 cm-1. The peaks of the possible aldehyde would mask the peaks normally seen when an aromatic ring is present.

1703 cm-1: This strong peak suggests an aldehyde attached to an aromatic ring as when this is the case the aldehyde is moved down from the 1720 cm-1 region to around 1700 cm-1.

746 & 688 cm-1: These strong peaks suggest a mono substituted aromatic ring C-H bending vibration. This information also supports the peak at 1703 cm-1 that an aldehyde is attached to an aromatic ring.

From the information above and using the list of controlled substances a possible structure for this sample is Benzaldehyde.

Possible Structure

Benzaldehyde

Conclusion

Based on the information gathered from the infrared spectra it is likely that the samples recovered have come from a clandestine laboratory which predominantly produced members of the amphetamine family. This conclusion has been reached as five of the possible compounds can be used in the production of amphetamines. These compounds are Ethyl Acetate, Benzyl Cyanide, MDMA, Nitroethane and Benzaldehyde.

Ethyl Acetate and Benzaldehyde can be used for the production of amphetamine. Benzyl cyanide and Benzaldehyde can be used for the production of phenyl-2-propanone. Nitroethane can be used in the production of MDMA. The other two compounds are γ-butyrolactone (GBL) and benzophenone. Neither of which are used in amphetamine production however GBL is a controlled substance as it can be used in the production of γ- Hydroxybutyric acid.

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