Examination of Firearms Review: 2007 to 2010 - Interpol

achiral separation of methadone, EDDP and EMDP was achieved, using a
capillary coated with a polycation of poly(diallyldimethylammonium chloride)
and a polyanion of dextran sulfate, with migration times of approximately 4 min
[260]. To further separate enantiomers of methadone and EDDP, another CE
method was developed using 0.2% highly sulphated gamma-cyclodextrins as
chiral selectors, giving LODs of 2.3-2.4 ng/mL with a 5 min runtime [261]. The
prevalence of elevated levels of CDT, a marker of chronic alcohol abuse in
serum of DUI drivers, was studied by CE. With a cut-off set at 2.00% (CDT
index), 24 out of 40 drunken drivers were identified as chronic alcohol abusers
[262].
Due to its selectivity and sensitivity, CE coupled to MS (CE-MS) has evolved
as a useful analytical tool for determining drugs and metabolites in biological
samples. Non-aqueous CE online coupled with a mass spectrometer for the
analysis of phosphatidylethanol (Peth), another biomarker of chronic alcohol
abuse in blood, was developed. With the use of phosphatidylbutanol as an
internal standard, the estimated LOD was 0.1 µM, while LOQ was 0.4 µM [263].
Determinations of illicit drugs and/or metabolites (opiates, cocaine,
amphetamines, and methadone) in blood [264] and in hair [265] by CE-MS,
were accomplished. LODs in blood were in the range of 2-10 ng/mL, while in
hair were 0.1 ng/mg. With the use of protein precipitation (PP) prior to a
hydrodynamic injection (HD) or liquid-liquid extraction (LLE) with electrokinetic
injection (EK), CE-ESI-MS methods for analysis of ecstasy and methadone in
plasma, were developed. Methods were linear over the concentration range of
0.50-175 ng/mL and 0.25-5 µg/mL for LLE-EK and PP-HD procedures,
respectively [266].
3.2 Extraction Techniques
3.2.1 Liquid-phase microextraction (LPME)
Liquid-liquid extraction (LLE) was one of the conventional sample preparation
techniques extensively used for biological sample analysis, particularly for
post-mortem toxicology. This method, however, is relatively time-consuming
and produces relatively large amount of organic solvent waste. Liquid-phase
microextraction (LPME), which requires much less organic solvent in the
pretreatment procedure, was recently developed [267,268,269]. There are
several types of LPME, including single-drop microextraction (SDME) [270],
dispersive liquid-liquid microextraction (DLLME) [ 271 ], and hollow-fiber
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