SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

A62
A FULLY AUTOMATED METHOD FOR THE SCREENING OF BASIS DRUGS IN WHOLE
BLOOD THROUGH ON LINE SPE-HPLC-DAD
Rafael Linden*
Instituto Geral de Pericias, Porto Alegre, RS, Brazil; Centro Universitario Feevale, Novo Hamburgo, RS,
Brazil
One of the major tasks in forensic toxicology laboratories, especially those with high workloads, is to
provide adequate drug screening analysis in a limited amount of time. The purpose of this work was to
develop a screening method, with reasonable discrimination capabilities, that could work unattended, using
an aumomated device for solid phase extraction (SPE) coupled to a HPLC-DAD. Postmortem blood
samples, (free of drugs) were spiked with cocaine, benzoylecgonine, lignocaine, diazepam, nordazepam,
fluoxetine and sertraJine, until final concentrations of 500 nglmL were achieved. The whole blood samples
were sonicated, than diluted from 3.5 to 7 mL with carbonate buffer (pH 9.3). The diluted samples were
centrifuged and the supemadant was used for SPE. The extraction was performed in an Aspec® system,
using Speed® C18 200mg cartridges, with the following steps: conditioning with 2 mL of methanol and 2
mL of carbonate buffer pH 9.3, loading of 6.5 mL of diluted samples, washing with 2 mL of 9: 1 carbonate
buffer:acetonitrile and eluting with 1 mL of 9: I acetonitrile:phosphate buffer pH 2.3. The solvents flows
and air pushes were optimized. The eluate was injected on line in the HPLC, using a 100 ilL loop. For the
hplc analysis, a C8 column, 25cm x 4.6 mm, was used in isocratic mode, with a mobile phase composed of
phosphate buffer and acetonitrile (63:37). The identification of the drugs was made based on their relative
retention times to imipramine (I.S.) and on a spectral library. Recoveries above 80% were obtained for all
drugs tested, with extracts sufficiently clean for hplc-dad identification. The method is now being
expanded to a bigger number of drugs, including a acidic fraction.
Key words: Solid phase extraction, Drug screening, HPLC-DAD
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