MoP-24


A DUAL DETECTION SYSTEM FOR THE SCREENING OF TOXICOLOGICAL SPECIMENS USING CAPILLARY GAS-CHROMATOGRAPHY WITH COMBINED NITROGEN PHOSPHORUS AND MASS SPECTROMETRIC DETECTION

Michael H. Phelan, Kerryn Crump, Alex Kotsos, Iain McIntyre and Olaf H. Drummer

Victorian Institute of Forensic Medicine and Department of Forensic Medicine, Monash University, 57-83 Kavanagh Street, Southbank 3006
Email: forensic@vifp.monash.edu.au


We have configured two sensitive and specific detection systems to a gas chromatograph (HP 5890) fitted with a 25 m x 0.32 mm I.D. Ultra 2 capillary column. The effluent of the column is split using a fused silica splitter and configured to a HP nitrogen-phosphorus detector and a quadrupole mass selective detector (HP 5972A).

Extracts of blood (plasma, urine and liver homogenates) specimens are prepared by treating 1 - mL of specimen with pH 9.0 buffer and extracting with 1 - chlorobutane. Internal standard is added prior to extraction. The solvent is evaporated and reconstituted into a small volume of methanol. Two µL volumes are usually injected in the splitless mode. Powders, residues from vials and syringes are usually treated with methanol just prior to chromatography.

This procedure allows the simultaneous detection and confirmation of substances sensitive to NPD free from significant interference from endogenous substances as well as other substances not readily detectable by NPD. Detection limits for many therapeutic drugs, illicit drugs and other poisons are sufficient for identification and confirmation at sub-therapeutic concentrations.