Combined capillary column gas chromatography/electron capture negative ion chemical ionization mass spectrometry of dihydropyridine calcium antagonists

Abstract

Several dihydropyridine calcium antagonists showed intense [M]-. ion peaks as the base peaks and a few fragment peaks in the electron capture negative ion chemical ionization mass spectra. The peak intensities of the [M]-. ion of these antagonists were about 100 times as high as those of the most abundant positive ion. The use of a capillary column connected directly to the ion source prevents the oxidation of these agents in the column and the transfer line. Furthermore, the presence of plasma extract decreases the oxidation of these agents in the injection port. The limits of sensitivity with this technique are 500 fg-5 pg on the column. Combined capillary column gas chromatography/electron capture negative ion chemical ionization mass spectrometry should be suitable for sensitive and specific assays of dihydropyridine calcium antagonists in biological fluids.

Felodipine quantification in human plasma by high-performance liquid chromatography coupled to tandem mass spectrometry

“…Several analytical methods based on high resolution gas chromatography (HRGC) mainly with electron capture detector [4][5][6], high performance liquid chromatography (HPLC) [7][8][9][10], HRGC coupled to mass spectrometry (HRGC-MS) [11][12][13] and HPLC coupled to mass spectrometry (HPLC-MS) [14] and recently by HPLC coupled to tandem mass spectrometry (HPLC-MS-MS) [15] has been used for the felodipine quantitation in plasma. These methods however, not are ideal to pharmacokinetics studies, because are laborious and include time-consuming procedures or long chromatographic run times (>10 min) [14].…”