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We describe a multi-method for simultaneous identification and quantification of 12 acidic and neutral compounds in whole blood. The method involves a simple liquid-liquid extraction, and the identification and quantification are performed using liquid chromatography-tandem mass spectrometry. The method was fully validated for salicylic acid, paracetamol, phenobarbital, carisoprodol, meprobamate, topiramate, etodolac, chlorzoxazone, furosemide, ibuprofen, warfarin, and salicylamide. The method also tentatively includes thiopental, theophylline, piroxicam, naproxen, diclophenac, and modafinil, but these drugs were not included in the full validation program and are not described in detail here. Limit of quantitation was 1 mg/kg for the compounds with coefficients of variation of < 20%, except for furosemide, which had a coefficient of variation of 32% at limit of quantitation. The measuring interval was wide for most components. Extraction efficiencies were high, reflecting the high-yield capacity of the method.

An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for detection of 23 benzodiazepines and related compounds in whole blood was developed and validated. The method is used for screening and quantitation of benzodiazepines in whole blood received from autopsy cases and living persons. The detected compounds were alprazolam, bromazepam, brotizolam, chlordiazepoxide, demoxepam, clobazam, clonazepam, 7-aminoclonazepam, diazepam, nordiazepam, estazolam, flunitrazepam, 7-aminoflunitrazepam, lorazepam, lormetazepam, midazolam, nitrazepam, 7-aminonitrazepam, oxazepam, temazepam, triazolam, zaleplon, and zopiclone. Whole blood from drug-free volunteers was used for all experiments. Blood samples (0.200 g) were extracted with ethyl acetate at pH 9. Target drugs were quantified using a Waters ACQUITY UPLC system coupled to a Waters Quattro Premier XE triple quadrupole in positive electrospray ionization, multiple reaction monitoring mode. The use of deuterated internal standards for most compounds verified that the accuracy of the method was not influenced by matrix effects. Extraction recoveries were 73-108% for all analytes. Lower limits of quantification ranged from 0.002 to 0.005 mg/kg. Long-term imprecision (CV%) ranged from 6.0 to 18.7%. We present a fully validated UPLC-MS-MS method for 23 benzodiazepines in whole blood with a run-time of only 5 min and using only 0.200 g of whole blood.