• Cocaine • Urine Drug Testing

Commonly abused for its strong affects as a central nervous stimulant, cocaine is a drug whose use is closely monitored in the United States and elsewhere. It is extracted and isolated from the South American shrub, Erythroxylon coca. Besides its use by abusers, cocaine has been utilized by the medical industry as a local anesthetic through topical application of its hydrochloride salt. When abused, it is usually taken either as the hydrochloride through injection or nasal inhalation or by smoking the free base.1 Workplace drug testing laboratories typically will look in urine for indications of its use. This is generally done by monitoring a primary metabolite, benzoylecgonine (BE), since in urine this compound is found in much higher concentration than cocaine after its use. The methodology described below details the confirmation and quantitation of benzoylecgonine (Figure 1) in urine using the DSQ ™ II GC/MS system. Figure 1: Chemical structure of benzoylecgonine For this assay, a 2 mL urine sample size was used, with benzoylecgonine-D3 as the deuterated internal standard. Samples were extracted using solid phase extraction. After extraction, the samples were derivatized with hexafluoro-isopropanol (HFIP), using pentafluoropropionic acid (PFPA) as a catalyst. The final reaction products were analyzed using a DSQ II single stage quadrupole GC/MS system. A calibrator at 150 ng/mL was used for single point calibration. The resulting method demonstrated excellent precision, no interference for a number of tested compounds and provided linearity from 15 to 12,500 ng/mL, with a limit of detection and limit of quantitation of 15 ng/mL