摘要
Chromatographic behavior of co-eluted compounds from un-extracted drug-free plasma samples was studied by LC-MS and LC-MS/MS with positive APCI.Under soft gradient,total ion chromatogram（TIC） consisted of two major peaks separated by a constant lower intensity region.Early peak（0.15-0.4 min） belongs to polar plasma compounds and consisted of smaller mass ions（m/z〈 250）;late peak（3.6-4.6 min） belongs to thermally unstable phospholipids and consisted of fragments with mlz〈300.Late peak is more sensitive to variations in chromatographic and MS parameters.Screening of most targeted cardiovascular drugs at levels lower than 50 ng/mL has been possible by LC-MS for drugs with retention factors larger than three.Matrix effects and recovery,at 20 and 200 ng/mL,were evaluated for spiked plasma samples with 15 cardiovascular drugs,by MRM-LC-MS/MS.Average recoveries were above 90%and matrix effects expressed as percent matrix factor（%MF） were above 100%,indicating enhancement character for APCI.Large uncertainties were significant for drugs with smaller masses（m/z〈 250） and retention factors lower than two.
Chromatographic behavior of co-eluted compounds from un-extracted drug-free plasma samples was studied by LC-MS and LC-MS/MS with positive APCI.Under soft gradient,total ion chromatogram（TIC） consisted of two major peaks separated by a constant lower intensity region.Early peak（0.15-0.4 min） belongs to polar plasma compounds and consisted of smaller mass ions（m/z〈 250）;late peak（3.6-4.6 min） belongs to thermally unstable phospholipids and consisted of fragments with mlz〈300.Late peak is more sensitive to variations in chromatographic and MS parameters.Screening of most targeted cardiovascular drugs at levels lower than 50 ng/mL has been possible by LC-MS for drugs with retention factors larger than three.Matrix effects and recovery,at 20 and 200 ng/mL,were evaluated for spiked plasma samples with 15 cardiovascular drugs,by MRM-LC-MS/MS.Average recoveries were above 90%and matrix effects expressed as percent matrix factor（%MF） were above 100%,indicating enhancement character for APCI.Large uncertainties were significant for drugs with smaller masses（m/z〈 250） and retention factors lower than two.
基金
supported by Dean of Scientific Research at Jordan University of Science and Technology(JUST)(No.159/ 2012)
