Effects of Additives to Methyl Hydroperoxyoleates on the Formation of Protonated Molecules and/or Molecular Adduct Ions in Liquid Ionization Mass Spectrometry.

Abstract

Effects of additives, introduced to a sample through vapor phase, on the formation of protonated molecules and/or molecular adduct ions were investigated in liquid ionization mass spectrometry for the analysis of methyl hydroperoxyoleates. Water and formic acid having small proton affinities were useful for increasing ion abundance of protonated molecules [M+H]+. 2-Aminoethanol and pyridine having slightly greater proton affinities were useful for forming molecular adduct ions [M+H+L]+ (L: additive molecule). The use of additives, acting as matrix for producing [M+H]+ and/or as reagent for forming [M+H+L]+ in liquid ionization mass spectrometry, provided useful mass spectral characteristics of the molecular weight and structure of unknown compounds.