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A chemical ionization selected ion monitoring assay for methylphenidate and ritalinic acid
Author(s) -
Iden Charles R.,
Hungund Basalingappa L.
Publication year - 1979
Publication title -
biomedical mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0306-042X
DOI - 10.1002/bms.1200061003
Subject(s) - diazomethane , methylphenidate , chemistry , calibration curve , chromatography , chemical ionization , ion , detection limit , gas chromatography , protonation , ionization , organic chemistry , medicine , attention deficit hyperactivity disorder , psychiatry
A methane chemical ionization quantitative assay for methylphenidate and its major metabolite, ritalinic acid, is described. Methylphenidate and the internal standard, ethylphenidate, were extracted from plasma samples and derivatized to prevent thermal decomposition in the gas chromatograph. Ritalinic acid was esterified with diazomethane and extracted as methylphenidate. The intensity of the protonated molecular ion of the derivatized drug and internal standard was measured by selected ion monitoring. Calibration curves were prepared from drug standards dissolved in drug‐free plasma, and the lower limit of the curves extended to 0.5 ng methylphenidate per ml plasma. The method was used to generate plasma decay curves for pediatric patients undergoing methylphenidate therapy.