title: Accurate mass measurement in nano-electrospray ionization mass spectrometry by alternate switching of high voltage between sample and reference sprayers.
abstract: An electrospray dual sprayer, which generates separate sample and reference sprays by alternately switching the high voltage between the two sprayers, is described. The technique permits accurate mass measurements in nano-electrospray ionization mass spectrometry (ESI-MS) to be obtained using a quadrupole/orthogonal acceleration time-of-flight mass spectrometer (Q-TOF). Similar to the method employed with a dual ESI source (Wolff JC et al., Anal. Chem. 2001; 73: 2605), the two sprays are orthogonal with respect to each other, but can be independently sampled without any baffle between these sprays. The reference sprayer is used in the original configuration of the ESI source and was optimized for a 1-2 muL/min flow, whereas the sample sprayer can be either a conventional glass capillary or a borosilicate tip of the type used for nano-ESI. Both sprayers can be positioned close to the cone so as to give maximum ion currents. The sample and reference sprays are independently generated by raising the potentials on the sample and reference sprayers to 1.4 and 3.0 kV, respectively; the high voltages can be rapidly turned on and off in ca. 1 ms. A nano-ESI-MS or nano-flow LC/ESI-MS experiment using a Q-TOF coupled with the above system gave mass accuracies within 3 ppm for measurements of ions up to m/z 1000 using subpicomole samples.
authors.affiliation: Laboratory of Protein Profiling and Functional Proteomics, Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Satomi
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Kudo
authors.forename: Kyoko
authors.initials: K
authors.lastname: Sasaki
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Hase
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Takao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D053379:Chromogranin A; D002864:Chromogranins / Q000737:chemistry; D010450:Endopeptidases; D008832:Microchemistry / Q000379:methods*; D008969:Molecular Sequence Data; D036103:Nanotechnology; D010455:Peptides / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D012015:Reference Standards; D015203:Reproducibility of Results; D012710:Serum Albumin, Bovine / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D013373:Substance P / Q000737:chemistry; D018822:alpha-Endorphin / Q000737:chemistry
chemical_list: D053379:Chromogranin A; D002864:Chromogranins; D010455:Peptides; D012710:Serum Albumin, Bovine; D013373:Substance P; D018822:alpha-Endorphin; D010450:Endopeptidases