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Title: Trace metal analysis of street drugs by atomic absorption spectroscopy
Author: French, Holly
Awarding Body: University of Kent
Current Institution: University of Kent
Date of Award: 2013
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The aim of the study was to ascertain the capabilities of the graphite furnace atomic absorption spectroscopy (OF AAS) system to discriminate between the two separate ecstasy batches according to the differing concentrations of trace metals. Previous studies have utilised rcp techniques such as rCP-AES and rCP-MS to determine trace metal concentrations in ecstasy tablets with particular interest in potential synthesis marker metals such as Pt, B and Hg. Five metals: Cu, Ba, Ni, Cr and Ph were quantified with good repeatability and reproducibility. The selection of elements comprises of metals that may be present due to additives, dyes, reducing agents, catalysts and elements recorded to be commonly present in ecstasy tablets, for example Ba. Elements Cu, Cr and Pb have been observed previously to be more homogenous within batches than elemental markers for synthesis routes suggesting these trace metals will be of use for indicating linkages between batches. Two separate batches of seized ecstasy tablets were analysed by GF AAS following digestion with nitric acid and hydrogen peroxide. Ecstasy tablets were acquired from the TICTAC unit at St George's Hospital London Tooting. HPLC analysis conducted at St. George's indicated that Batch 21573 of 20 tablets contained significant quantities of MDMA while Batch 26237 of 20 tablets contained predominantly caffeine. The small sample size has allowed for careful interpretation of intra-batch variation and inter-batch variation in the metal concentrations determined for each ecstasy batch. A previous study has used a similar sample size. The current study has successfully demonstrated the quantitation of five trace metals in ecstasy tablets for the first time via OF AAS. Large intra-batch variations were fOlU1d as expected for tablets produced in clandestine laboratories. Nickel in the MDMA containing batch 21573 was present in the range 0.47-13.1 ppm and in the caffeine containing batch 26237 in the range 0.35-9.06 ppm, very similar to previous reports of 1- 25 ppm and 0.3-16 ppm. The Cr levels detenmined in the current study (MDMA batch: 0.12-3.16 ppm, caffeine batch: 0.10-1.36 ppm) are lower than reported previously (0.7-34 ppm). The range ofPb concentrations (MDMA batch: 0.1 1-3.81 ppm, caffeine batch: 0.12- 4.91 ppm) are similar to previously reported (0.02-10 ppm). The copper levels in these samples were found to be particularly high (MDMA batch: 4-2379 ppm, caffeine batch: 17-1851 ppm) compared with previous studies using ICP techniques which fOlU1d ranges of 1-19 ppm and 0.8-38 ppm in ecstasy tablets. Barium concentrations were relatively similar within each batch with significantly higher concentrations found in the caffeine containing batch 26237 (rv1DMA batch: 0.19-0.66 ppm, caffeine batch: 3.77-5.47 ppm). Barium was the only element to offer discrimination between the two batches of tablets. AAS systems are well established, cheaper to install and run, and require less user skill as well as less sample volume. The addition that the current study offers in light of previous literature in the area is evidence of the capabilities of GF AAS to perform analyses on ecstasy tablets, with good detection limits, good precision and small sample volume, but with a technique that is well establish, fmancially less challenging and readily available in forensic laboratories in comparison to the more powerful ICP-MS technique
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available