SIMULTANEOUS DETECTION OF METHYLPHENIDATE AND ITS MAIN METABOLITE, RITALINIC ACID, IN DOPING CONTROL

Two analytical methods for the simultaneous detection in urine of meth ylphenidate and its main metabolite, ritalinic acid, are described. Bo th procedures are based on solid-phase extraction of urine samples on Bond Elut Certify columns, and capillary gas chromatographic-mass spec trometric detection of O-trimethylsilyl, N-trifluoroacetyl derivatives . The former method is used as a general screening procedure for the d etection of basic polar nitrogen-containing compounds in urine such as stimulants, narcotic and adrenergic drugs. The latter procedure is pr oposed as a specific method to confirm methylphenidate ingestion. The two methods are sensitive enough to detect methylphenidate and ritalin ic acid in urine at least for 24 h after administration of a therapeut ic dose (20 mg oral dose) of methylphenidate.