Protein Analysis by Electrospray-Orbital Frequency Analyzer with Charge Detection Mass Spectrometry Algorithm.

Orbital frequency analyzer (OFA) is one of the electrostatic ion trap mass analysers for FTMS, which offers ultrahigh mass resolution and high ion charge capacity. In order to analyze multiply charged proteins and other large biological particles by means of charge detection mass spectrometry, a data processing algorithm was created to suit the image charge signal of nonharmonic waveform nature. The algorithm is capable of detecting collisions between ions and residual gas molecules, to determine lifetime of ions, and to evaluate the charge and mass values for ions having lifetime above a threshold.

Structural characterization of neutral glycosphingolipids using high-performance liquid chromatography-electrospray ionization mass spectrometry with a repeated high-speed polarity and MSn switching system.

Four types of neutral glycosphingolipids (LacCer, Gb3Cer, Gb4Cer, and IV3αGalNAc-Gb4Cer; 10 pmol each) were analyzed using high-performance liquid chromatography (HPLC)-electrospray ionization quadrupole ion trap time-of-flight (ESI-QIT-TOF) mass spectrometry (MS) with a repeated high-speed polarity and MSn switching system. This system can provide six types of mass spectra, including positive and negative ion MS, MS2, and MS3 spectra, within 1 s per cycle. Using HPLC with a normal-phase column, information on the molecular weights of major molecular species of four neutral glycosphingolipids was obtained by detecting [M+Na]+ in the positive ion mode mass spectra and [M−H]− in the negative ion mode mass spectra.

Structural characterization of pyridylaminated oligosaccharides derived from neutral glycosphingolipids by high-sensitivity capillary electrophoresis-mass spectrometry.

High-sensitivity capillary electrophoresis-electrospray ionization quadrupole ion trap time-of-flight mass spectrometry (CE-ESI-QIT-TOF MS) was developed to structurally characterize four kinds of pyridylaminated (PA) oligosaccharides, i.e., lactose (Lac)-PA, globotriose (Gb3)-PA, globotetraose (Gb4)-PA, and IV(3) αGalNAc-Gb4 (Forssman antigen)-PA, derived from neutral glycosphingolipids.

Structural characterization of monosialo-, disialo- and trisialo-gangliosides by negative ion AP-MALDI-QIT-TOF mass spectrometry with MS(n) switching.

The atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI) is a quite convenient soft ionization for biomolecules, keeping analytes atmospheric conditions instead of high vacuum conditions. In this study, an AP-MALDI ion source has been coupled to a quadrupole ion trap time-of-flight (QIT-TOF) mass spectrometer, which is able to perform MS(n) analysis. We applied this system to the structural characterization of monosialogangliosides, GM1 (NeuAc) and GM2 (NeuAc), disialogangliosides, GD2 (NeuAc, NeuAc), GD1a (NeuAc, NeuAc) and GD1b (NeuAc, NeuAc) and trisialoganglioside GT1a (NeuAc, NeuAc, NeuAc).