Comprehensive automation of the solid phase extraction gas chromatographic mass spectrometric analysis (SPE-GC/MS) of opioids, cocaine, and metabolites from serum and other matrices

Abstract

The analysis of opioids, cocaine, and metabolites from blood serum is a routine task in forensic laboratories. Commonly, the employed methods include many manual or partly automated steps like protein precipitation, dilution, solid phase extraction, evaporation, and derivatization preceding a gas chromatography (GC)/mass spectrometry (MS) or liquid chromatography (LC)/MS analysis. In this study, a comprehensively automated method was developed from a validated, partly automated routine method. This was possible by replicating method parameters on the automated system. Only marginal optimization of parameters was necessary. The automation relying on an x-y-z robot after manual protein precipitation includes the solid phase extraction, evaporation of the eluate, derivatization (silylation with N-methyl-N-trimethylsilyltrifluoroacetamide, MSTFA), and injection into a GC/MS. A quantitative analysis of almost 170 authentic serum samples and more than 50 authentic samples of other matrices like urine, different tissues, and heart blood on cocaine, benzoylecgonine, methadone, morphine, codeine, 6-monoacetylmorphine, dihydrocodeine, and 7-aminoflunitrazepam was conducted with both methods proving that the analytical results are equivalent even near the limits of quantification (low ng/ml range). To our best knowledge, this application is the first one reported in the literature employing this sample preparation system.

Assessing Cocaine Abuse Using LC–MS/MS Measurements in Biological Specimens

“…Assessing cocaine abuse using LC-MS/MS measurements in biological specimens Mário For reprint orders, please contact reprints@future-science.com substances or the need for chemical derivatization of functional moieties prior to chromatography, the latter involving in general laborious and time-consuming procedures [18,19].…”

Optimization and validation of simultaneous analyses of ecgonine, cocaine, and seven metabolites in human urine by gas chromatography–mass spectrometry using a one‐step solid‐phase extraction

“…Most GC-MS methods for the analysis of COC and metabolites require a derivatization process to increase volatility, stability or detectability, and to facilitate chromatographic separation. The most common agents described in the literature are N-methyl-N--(trimethylsilyl) trifluoroacetamide (MSTFA), 26,27 N,O-bis (trimethylsilyl) trifluoroacetamide (BSTFA), 28 pentafluoropropionic anhydride (PFPA) 29 and pentafluoropropanol (PFPOH). 29 In the present work, we have used PFPA and HFP for the simultaneous derivatization of alcoholic, phenolic, secondary amino and carboxylic groups of the analytes.…”

Gas‐phase fragmentation reactions of protonated cocaine: New details to an old story

“…Gas chromatography‐mass spectrometry (GC‐MS) provides higher sensitivity than liquid chromatography mass spectrometry (LC‐MS). Therefore, GC‐MS is often the analytical technique of choice when it comes to screening cocaine and its metabolites . Unfortunately, GC‐MS requires chemical derivatization to obtain appropriate thermally labile analogs before analysis, but derivatization reagents can mask results, which is an important drawback of this technique .…”