Discovery of syn-/anti-cocaine-N-oxide diastereomers in unwashed postmortem hair via LC-MS-MS.

The discovery of two cocaine-N-oxide (CNO) diastereomers, syn- and anti-CNO, is reported for the first time. Prior to this study, only one structural form of CNO was known to exist and has not been analyzed in hair before. CNO is a metabolite of cocaine (COC) and may be considered as an additional biomarker of COC use, along with other known COC metabolites.