title: Simultaneous mass analysis of positive and negative ions using a dual-polarity time-of-flight mass spectrometer.
abstract: Positive and negative ions produced from matrix-assisted laser desorption/ionization (MALDI) were simultaneously measured using a newly developed dual-polarity time-of-flight mass spectrometer. This instrument is effective not only for express and comprehensive mass analysis but also for studying the ionization mechanisms of biomolecules. It comprises two identical time-of-flight mass analyzers located symmetrically about a MALDI ion source. The ion optics are arranged to be able to extract positive and negative ions synchronously with equal efficiency to each corresponding mass analyzer. Mass spectra of various proteins with molecular weights as large as that of myoglobin monomer and dimer were obtained. The spectral patterns obtained in this work are approximately mirror images with opposite polarities.
authors.affiliation: Genomics Research Center, Academia Sinica, 128, Academia Road, Section 2, Nankang District, Taipei 115, Taiwan, ROC.
authors.forename: Shang-Ting
authors.initials: ST
authors.lastname: Tsai
authors.forename: Chiu Wen
authors.initials: CW
authors.lastname: Chen
authors.forename: Ling Chu
authors.initials: LC
authors.lastname: Lora
authors.forename: Min-Chia
authors.initials: MC
authors.lastname: Huang
authors.forename: Chung-Hsuan
authors.initials: CH
authors.lastname: Chen
authors.forename: Yi-Sheng
authors.initials: YS
authors.lastname: Wang
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000032:analysis / Q000737:chemistry; D000803:Angiotensin I / Q000032:analysis / Q000737:chemistry; D000838:Anions / Q000032:analysis* / Q000737:chemistry; D002412:Cations / Q000032:analysis* / Q000737:chemistry; D045424:Complex Mixtures / Q000032:analysis* / Q000737:chemistry; D019281:Dimerization; D007328:Insulin / Q000032:analysis / Q000737:chemistry; D008970:Molecular Weight; D009211:Myoglobin / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D000838:Anions; D002412:Cations; D045424:Complex Mixtures; D007328:Insulin; D009211:Myoglobin; D000324:Adrenocorticotropic Hormone; D000803:Angiotensin I