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第1日 6月17日(水)  P会場

Analysis of Labile Ions in a Linear Ion Trap Mass Spectrometer

(1KRISS2CBNU3Samsung)
Lee, Hyun-seok1,2Shin, Kyong-oh2Jo, Sung-chan3Lee, Yong-moon2oYim, Yong-hyeon1

The fragmentation of fragile ions during the application of an isolation waveform for precursor ion selection and the resulting loss of isolated ion intensity is well known in ion trap mass spectrometry (ITMS). To obtain adequate ion intensity in the selected reaction monitoring (SRM) of fragile precursor ions, a wider ion isolation width is required. However, the increased isolation width significantly diminishes the selectivity of the channels chosen for SRM, which is a serious problem for samples with complex matrices. The sensitive and selective quantification of many lipid molecules, including ceramides from real biological samples, using a linear ion trap mass spectrometer is also hindered by the same problem due to the ease of water loss from protonated ceramide ions. In this study, a method for the reliable quantification of ceramides using SRM with near unity precursor ion isolation has been developed for ITMS by utilizing alternative precursor ions generated by in-source dissociation. The selected precursor ions allow the isolation of ions with unit mass width and the selective analysis of ceramides using SRM with negligible loss of sensitivity. The developed method was successfully validated for qunatification of C18:0, C24:0 and C24:1 ceramides and applied to quantify them in fetal bovine serum.