GC/MS analysis of m-hydroxybenzoylecgonine in urine. Forensic implication in cocaine use.

m-Hydroxybenzoylecgonine (m-OH-BE) and d3-m- hydroxybenzoylecgonine (d3-m-OH-BE) have been synthesized, and a GC/MS procedure with d3-m-OH-BE as internal standard has been developed. Among 24 human urine specimens that were positive for BE, all of them have shown detectable levels of m-OH-BE with 75% of the specimens exceeding the LoQ (5 ng/mL), compared with only 50% of the specimens containing detectable levels of EME. The presence of m-OH-BE in urine suggested that this metabolite may serve as a valuable marker of cocaine use in addition to BE and EME.