Development of Nano-ESI Probe and Studies on Decomposition Mechanism of Several Organic Ions by Using High-Resolution Mass Spectrometry and MIKE Spectrometry

Abstract

A new technique is described for accurate mass measurement by using multiple sprayers nano electrospray ionization mass spectrometry (nano-ESI/MS). A nano-scale high-performance liquid chromatography (nano-LC) was combined with a magnetic sector instrument. A metal-coated glass capillary was used for the introduction of the reference compound solution, and a metal-coated fused silica capillary was used to connect the nano-LC column to ionization chamber. By shifting the position of the each sprayers to the sampling orifice, the spectra were obtained for the sample compounds eluted from the column and the reference one. Several standard compounds were examined by using this technique and satisfactory accurate masses were obtained. It was not problems for the differences between the ionization efficiency of the sample and the reference compounds. Studies on the unimolecular metastable ion decomposition of several organic compounds are also described by using high-resolution mass spectrometry, MIKE (mass-analyzed ion kinetic energy) spectrometry and D-labeling technique. The m/z 45 ions generated from 2-methoxyethylamine (CH₃OCH₂CH₂NH₂) consist of two isobaric ions, methoxymethyl ion, CH₃OCH₂⁺, and C₂H₇N⁺. The m/z 69 ions generated from methyl trifluoroacetoacetate (CF₃COCH₂COOCH₃) and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (CF₃COCH₂COCF₃) also consist of two isobaric ions, trifluoromethyl ion, CF₃⁺, and protonated carbon suboxide, OCCH⁺CO.