Gas-chromatographic quantification of methylphenidate in plasma with use of solid-phase extraction and nitrogen-sensitive detection.
The gas-chromatographic assay for methylphenidate described here involves isolation by solid-phase extraction and quantification by thermionic nitrogen-phosphorus detection. Methylphenidate and the internal standard, ethylphenidate, are extracted from plasma by partition onto C2 reversed-phase packing. Methylphenidate and ethylphenidate are eluted, dried, derivatized with trifluoroacetic anhydride, and gas-chromatographed, with nitrogen-sensitive detection. The standard curve for the assay is linear in the range 5-100 micrograms/L. The within-run CV is less than 4%, the between-run CV less than 6%. Mean analytical recovery of methylphenidate was greater than 90%. The smallest measurable concentration is 2 micrograms/L. The sensitivity, reproducibility, and economy of this assay make it suitable for clinical monitoring and pharmacokinetic studies.
D002648:Child; D002653:Child Behavior Disorders / Q000097:blood / Q000188:drug therapy; D002849:Chromatography, Gas; D005463:Fluoroacetates; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000031:analogs & derivatives / Q000097:blood* / Q000302:isolation & purification / Q000627:therapeutic use; D012015:Reference Standards
D005463:Fluoroacetates; D008774:Methylphenidate; C042400:ethylphenidate