A Simple Quantitation Method for Benzoylecgonine from Oral Fluid, Blood, and Urine Samples Used for Determining 22 Illicit and Licit Drugs by GC–MS with Liquid–liquid Extraction

The analytical system used for determination of 22 illicit and licit drugs by gas chromatography–mass spectrometry following liquid–liquid extraction has been extended with an additional extraction step with n-butyl acetate:CH2Cl2 = 1:8 to determine benzoylecgonine from the same oral fluid, blood, or urine samples. The extraction recovery of benzoylecgonine was 39.7% for oral fluid, 14.9% for blood, and 26.7% for urine; the cutoffs were 25, 8.0, and 8.0 ng/ml, respectively. The method was fully validated and proved suitable in further proficiency tests and for analysis of 2738 oral fluid, 197 blood, and 1298 urine samples.