Identification and Characterization of Isomeric Intermediates in a Catalyst Formation Reaction by Means of Speciation Analysis Using HPLC-ICPMS and HPLC-ESI-MS

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• 作者：Qiang Tu ; Tiebang Wang ; Christopher J. Welch ; Peng Wang ; Xiujuan Jia ; Conrad Raab ; Xiaodong Bu ; Darren Bykowski ; Benjamin Hohenstaufen ; and Michael P. Doyle
• 刊名：Analytical Chemistry
• 出版年：2006
• 出版时间：February 15, 2006
• 年：2006
• 卷：78
• 期：4
• 页码：1282 - 1289
• 全文大小：233K
• 年卷期：v.78,no.4(February 15, 2006)
• ISSN：1520-6882

文摘

Information on chemical speciation is much needed inmechanistic and kinetic studies on catalyst formationprocesses in pharmaceutical research. Speciation analysiswas applied to the identification and quantification ofvarious rhodium species involved in a ligand exchangeprocess leading to formation of catalyst dirhodium(II)tetrakis[methyl 2-oxopyrrolidin-5(S)-carboxylate]. Inductively coupled plasma mass spectrometry (ICPMS) wasused as an element-specific detector following speciesseparation by reversed-phase high-performance liquidchromatography (RP-HPLC), and electrospray ionizationmass spectrometry (ESI-MS) was used for species identification and confirmation. A novel interface between theHPLC and ICPMS, which consisted of an eluent splitter,a desolvation unit, and the ICPMS built-in peristalticpump, enabled the use of RP-HPLC with gradient elutionand up to 100% organic components in the LC eluentwithout organic loading in the plasma. A variety of reactionintermediates were identified and quantified along thepathway to formation of the desired product, includingisomeric di-, tri-, and tetrasubstituted species previouslybelieved to be absent. This has provided new insights intothe mechanism and kinetics of the reaction. The combination of HPLC-ICPMS and HPLC-ESI-MS has proven tobe a valuable tool for the investigation of species evolutionin catalyst formation process.