Detection and confirmation of cocaine and cocaethylene in serum emergency toxicology specimens

We report the performance of a liquid chromatography (LC) assay for detection and confirmationof cocaine and cocaethylene in serum. A photodiode array (PDA) detec-tor monitors the cyano column effluent at 230 nm for analyte detection. Confirmation of a peak’s identity is performed by use of only the 226-254-nm segment of the spectra rather than a broader range such as 210-340 nm. Use of the narrower range improves the assay’s sensitiv-ity by almost 10-fold. Analyte values of 10 g/L are confirmed routinely. Intra-assay imprecision at 100, 20, and 10 1zg/L for cocaine is 5.1%, 5.7%, and 6.6 % (CV), respectively. Absolute recovery of the analytes exceeds 80%. In a split-sample study (33 positives and 74 nega-tives), each of this method’s cocaine findings were con-firmed. Cocaethylene was found in 15 of these samples