Determination of theophylline in serum by high performance liquid chromatography/mass spectrometry with atmospheric pressure chemical-ionization (APCI HPLC/MS)
Susanto, F.; Reinauer, H.
Fresenius' Journal of Analytical Chemistry 357(3): 338-344
1997
ISSN/ISBN: 0937-0633
DOI: 10.1007/s002160050164
Accession: 008449037
A method for the determination of theophylline (TH), without derivatization, in serum by isotope dilution mass spectrometry using labelled (1,3-15N-2-2-13C)theophylline (LTH) as internal standard is described. After deproteinization, the analyte is directly injected into a high performance liquid chromatography - mass spectrometer operating with atmospheric-pressure chemical-ionization (APCI HPLC/MS). The concentrations of TH in sera measured by APCI HPLC/MS are compared with results from gas chromatography - isotope dilution mass spectrometry (GC-ID/MS), high performance liquid chromatography (HPLC) and fluorescence polarization immunoassay (FPIA). The accuracy, precision and recovery of the APCI HPLC/MS and GC-ID/MS methods are discussed. The coefficient of variation (CV) determined from duplicate samples was less than 2%. The detection limit was 10 ng/ml at a signal-to-noise ratio of 3:1.