2020 Volume 69 Issue 3 Pages 115-120
Electrospray ionization (ESI), the most general ionization method in LC/MS, is a representative example of soft ionization, and usually does not generate fragment ions. However, in some compounds which have a hydroxyl group, [M+H]+, [M+Na]+, [M+NH4]+, etc. are not generated by positive ions, and dehydration from [M+H]+ and [M+H-H2O]+ are mainly observed. If such ions are observed in the measurement of an unknown sample, it will cause inconvenience when acquiring mass information of the analyte. In this study, in the ESI used for on-line LC/MS, the dehydration ions [M+H-H2O]+ from [M+H]+ are mainly observed at normal desolvation temperatures. This paper reports a method for obtaining mass information of an analyte correctly from changes in mass spectral patterns by lowering the desolvation temperature. The performance was demonstrated using cholesterol, eudesmol and hinesol.