QUANTITATIVE-ANALYSIS QUANTITATION OF 2-N-NONYL-1,3-DIOXOLANE BY STABLE-ISOTOPE DILUTION GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

We report here a quantitative methodology developed for determination of SEPA (2-n-nonyl-1,3-dioxolane) in human serum. The method employed solid-phase extraction of SEPA and internal standard, [C-13(2)]SEPA, f rom serum followed by gas chromatography-mass spectrometry analysis us ing EI monitoring m/z 73 and 75. We have investigated the utility of s table isotope dilution gas chromatography-mass spectrometry (GC-MS) fo r the determination of SEPA concentrations in serum using chemical ion ization (positive ion, CI) or electron ionization (EI). The comparison of the specificity and sensitivity between EI and CI indicated that m onitoring the m/z 73 ion in EI was superior to monitoring either MH+ o r m/z 73 using CI, The method was simple, sensitive and accurate, demo nstrating a lower limit of quantitation (LLOQ) of 0.25 ng/ml and intra -and inter-assay accuracy and precision of less than or equal to 7.5%. (C) 1998 Elsevier Science B.V.