Michelle Carlin

Forensic Applications of Gas Chromatography

Several areas of forensic science use the technique of gas chromatography, ranging from fire analysis to the investigation of fraudulent food and perfumes. Covering the essentials of this powerful analytical technique, Forensic Applications of Gas Chromatography explains the theory and shows applications of this knowledge to various realms of forensic science.

W3: The French experience of establishing an oral fluid roadside drug test

Introduction In 2005, following on from the findings of the ROSITA and DrUID projects, the French government made the decision to investigate possible alternative matrices to urine for drug screening at the roadside. A special committee, which included French ministerial representatives, was established in 2006 and they decided to use a special procurement contract in the form of a “competitive dialogue”: this allowed manufacturers of screening devices to improve their product in accordance with the committee’s recommendations. From initial investigations carried out, oral fluid (OF) was found to be the best alternative matrix (non invasive sample taking, difficult to adulterate, existing prototypes), and so this was chosen for this work. The devices included in the work were screening tests based on immunochromatographic methods. Method In France the four major categories of drugs tested for are cannabis, cocaine, opiates and amphetamines therefore the devices selected had to detect these compounds. The French gendarmerie and police played an important role in this previously unfamiliar testing and 3 OF devices remained for evaluation in the final step of the selection process. For this step, 2 field evaluation studies were carried out in 3 of the most active territorial road units by the Centre of Research and Expertise on Logistic (CREL). In the first study, approximately 500 individuals were involved. A urine sample was collected for screening, if positive a blood sample for confirmation and one of the OF devices was tested. In the second study, 100 participants were involved and standard urine and blood confirmation was carried out but also OF was tested against all three of the devices for a comparative study. The toxicology unit of our laboratory performed more than 400 of the confirmatory analyses by a validated GC-MS method. For both of the field studies, CREL processed the findings from the roadside units carrying out the screening and determined sensitivity, specificity and efficacy of the 3 devices. As a result, the Rapid Stat ® (Mavand) screening device was introduced for roadside drug testing. French law was subsequently modified in July 2008 to allow the use of an OF screening test operated by a police officer (as opposed to medical personnel). Results & discussion This change in legislation has resulted in a dramatic increase in the number of roadside drug tests performed and consequently the number of confirmatory analyses in blood (an increase from 15,000 in 2004 to 76,000 in 2010). Although OF has a number of factors requiring consideration when collecting, analysing and interpreting findings, it has become an accepted matrix for this type of testing and one which we are investigating. In March 2011, a new public contract was announced. A new device (Drugwipe5S ® , Securetec) was appointed, for 2011 to 2015. Last year, the Directorate General of the French Gendarmerie tasked our laboratory to carry out a feasibility study on the use of OF in confirmatory analyses. This includes evaluating financial, organisational and philosophical implications and establishing risk assessment criteria. With help from laboratories in Belgium and Switzerland, the analytical component of this study is now underway and several steps are planned, including the selection of the OF collection device, the choice of biological markers and the validation of both field testing devices and analytical methods. At this time, the collection device has already been chosen, the biological markers are being established and analytical method development is in progress. Since the work is in the early stages, no conclusion can be drawn as yet however, OF analysis offers us an interesting alternative matrix for future screening and confirmation.

Investigation of the acid/base behaviour of the opium alkaloid thebaine in LC-ESI-MS mobile phase by NMR spectroscopy

As part of a research programme to establish an analytical method for the simultaneous detection of the five major opium alkaloids in poppy seeds by liquid chromatography–electrospray ionization–mass spectrometry (LC-ESI-MS) it was discovered that the inclusion of thebaine produced two peaks for the same compound. This was in contrast to the effective simultaneous detection, by LC-ESI-MS, of morphine, codeine, papaverine and noscapine. The presence of these two peaks for thebaine was investigated using nuclear magnetic resonance spectroscopy with deuterated solvents to emulate the mobile phase conditions experienced. It was found that the presence of 80%, or higher ratios of, water caused two epimeric forms of thebaine to be formed; this explained the presence of two peaks on the chromatogram. In contrast, when a lower water content was used with 1% acetic acid, one stable form of thebaine could be analysed and resulted in a single peak visible in the subsequent chromatography.

Supplementary material from "Investigation of the acid/base behaviour of the opium alkaloid thebaine in LC-ESI-MS mobile phase by NMR spectroscopy"

As part of a research programme to establish an analytical method for the simultaneous detection of the five major opium alkaloids in poppy seeds by liquid chromatography–electrospray ionization–mass spectrometry (LC-ESI-MS) it was discovered that the inclusion of thebaine produced two peaks for the same compound. This was in contrast to the effective simultaneous detection, by LC-ESI-MS, of morphine, codeine, papaverine and noscapine. The presence of these two peaks for thebaine was investigated using nuclear magnetic resonance spectroscopy with deuterated solvents to emulate the mobile phase conditions experienced. It was found that the presence of 80%, or higher ratios of, water caused two epimeric forms of thebaine to be formed; this explained the presence of two peaks on the chromatogram. In contrast, when a lower water content was used with 1% acetic acid, one stable form of thebaine could be analysed and resulted in a single peak visible in the subsequent chromatography.

Forensic Science: Roadside Drug Testing

With drug abuse proving to be a continuing problem in society, it is no surprise that the detection of such abuse is an issue of importance. No more so than in the case of detection of drug impaired driving where the lives of many people may be placed at risk. With established method detection procedures and devices in place for alcohol, analytical chemists and other scientists are focussing their efforts on establishing analytical cut-offs and devices for the detection of drugs at the roadside. In this paper, the challenges faced in such a search are discussed. The main concerns arise from the choice of biological sample, the sampling methods employed, the device used for detection, and the cut-offs or detection limits for the devices. With many commercially available kits on the market, and none meeting the required standards at this time, a search for alternative methods is on going. Microfluidic devices may prove useful in this search however, more research is required in this area.