Isomer differentiation by combining gas chromatography, selective self‐ion/molecule reactions and tandem mass spectrometry in an ion trap mass spectrometer

This study presents a novel, simple and rapid procedure for isomer differentiation by combining gas chromatography (GC), a selective self‐ion/molecule reaction (SSIMR) and tandem mass spectrometry (MS/MS) in an ion trap mass spectrometer (ITMS). SSIMR product ions were produced from four isomers. For aniline, SSIMR induces the formation of the molecular ion, [M+H] + , [M+CH] + , adduct ions of fragments ([M+F] + , where F represents fragment ions) and [2MH] + . 2 and 3‐Picoline produce [M+H] + , [2MH] + and [M+F] + , while 5‐hexynenitrile produces [M+H] + , [M+F] + and [2M+H] + ions. The proposed method provides a relatively easy, rapid and efficient means of isomer differentiation via a SSIMR in the ITMS. Typically, isomer differentiation can be achieved within several minutes. The superiority of the SSIMR technique for isomer differentiation over electronic ionization (EI) is also demonstrated. Copyright © 2003 John Wiley & Sons, Ltd.