A routine screening method for the major metabolite of methyl phenidate in the urine of greyhounds

A qualitative urine screening procedure for the determination of the major urinary metabolite of methyl phenidate, alpha-phenyl-2-piperidine acetic acid (ritalinic acid), has been devised. The method involves a salting-out extraction, conversion of the metabolite to the parent drug using methanol-hydrogen chloride, and simultaneous two-column gas-chromatographic detection. Final confirmation of the presence of the drug is by two-system thin-layer chromatography. The method is suitable for the detection of illicitly administered methyl phenidate in greyhounds.