34 ANALYTICAL AND LABORATORY EQUIPMENT
Detection of ethyl glucuronide/ethyl sulphate in urine of sexual assault cases
Jeffery Hackett and Albert A Elian outline this process which uses an anion exchange solid phase extraction technique and LC-MS/ MS analysis.
O
f all the analyses carried out by forensic toxicology laboratories,
the determination of ethanol is probably the most common. Most forensic toxicology laboratories measure parent and metabolite concentrations of a variety of drugs in biological samples. However, the measurement of the metabolites of ethanol is rarely performed.
extraction to produce clean extracts for analysis by liquid chromatography-tandem mass spectrometry. Te method was then applied to genuine cases to determine the concentrations of both EtG/EtS where the ethanol in the urine sample was negative, but had been suspected.
EtG, EtS (1mg/mL in methanol), EtG-d5, EtS-d5
Diamond Hydride LC column (100mm x 2.1mm (4µm)) obtained from Microsolv using a mobile phase consisting of DI water w/0.1 per cent formic acid/acetonitrile w/0.1 per cent formic acid; (50: 50) at a flow rate of 0.35mL/minute.Te instrumentation used was a Shimadzu Prominence HPLC system. Te HPLC column was maintained at 40°C throughout the analyses. Tandem mass spectrometry was performed on an AB Sciex 3200 Qtrap in negative multiple reaction mode (MRM). Te mass spectrometric conditions are shown in Table 1.
Fig. 1. Structures: Ethanol (left) EtG (centre) EtS (right).
In this study, samples of urine taken from completed and signed out cases (ethanol related sexual assault) were analysed for the concentrations of ethyl glucuronide (EtG) and ethyl sulphate (EtS) using solid phase extraction (SPE) and LC-MS/MS. Tis study was initiated to develop a method that would assist forensic analysts in the quantification of EtG/EtS in urine samples. Te method is based on the employment of anion solid phase
Table 1. Tandem Mass Spectrometry conditions.
(0.1mg/mL in methanol), were obtained from Lipomed. Strong anion exchange/hydrophobic solid phase extraction (SPE) columns - CUQAX156 were obtained from UCT Inc. Methanol, acetic acid (glacial), formic acid, and acetonitrile (LC/MS grade) were obtained from Fisher Scientific. De- ionised (DI) water was generated in house.
Liquid chromatography was performed in isocratic mode on
SPE of urine samples (calibrators, controls, and test) was performed on CUQAX156 anion exchange columns pre-conditioned with methanol (3mL) followed by DI water (3mL) prior to sample loading. 0.5mL urine samples (containing deuterated analogues of EtG/EtS) were diluted with 4mL of DI water and mixed. After loading the samples onto the SPE columns, the cartridges were washed with DI water and methanol (3mL of each, respectively). Each SPE column was dried and eluted with 2 x
www.scientistlive.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68