title: Evaluation of hydrolysis and alcoholysis reactions in gas chromatography/mass spectrometry inlets.
abstract: During gas chromatography/mass spectrometry (GC-MS) analyses using water and methanol as injection solvents, hydrolysis reactions after injecting water control and alcoholysis reactions after injecting methanol control or ethanol into a GC-MS system were observed and studied. Two dominant hydrolysis/alcoholysis product series were detected, and were identified as being HO(CH₃)₂SiOR and HO(CH₃)₂SiO(CH₃)₂SiOR, where R=H, methyl, or ethyl, when pure water, methanol and ethanol were injected. The chemical structures of the reaction products were cross-checked by injecting H₂O/D₂O and H₂O/MeOH/EtOH, and comparable EI mass fragmentation patterns were found. The water and alcohols injected reacted with silicones in septum particles which accumulated in the injection port liner after numerous injections, and both hydrolysis and alcoholysis reaction products gradually increased in concentration as the number of injections increased. Potential interferences from hydrolysis or alcoholysis reactions should be paid attention to, evaluated or eliminated when water or methanol was used as the GC or GC-MS solvent, and especially when underivatized methanol or ethanol was subject to GC and GC-MS analysis.
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China. Electronic address: agm2006@163.com.
authors.forename: Guomin
authors.initials: G
authors.lastname: Ai
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 West Beichen Road, Chaoyang District, Beijing 100101, China.
authors.forename: Xiuzhu
authors.initials: X
authors.lastname: Dong
mesh_terms: D016477:Artifacts; D000431:Ethanol / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006868:Hydrolysis; D000432:Methanol / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D012828:Silicones; D012997:Solvents; D014867:Water; D000431:Ethanol; D000432:Methanol
keywords: Alcoholysis; Ethanol; GC inlet liner; Hydrolysis; Methanol; Septum particles