Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm, Germany.
Anal Chem. 2010 Mar 15;82(6):2472-9. doi: 10.1021/ac902847a.
We describe a novel method and setup for quantitative online analysis of the liquid-phase methanol oxidation products in acidic aqueous solutions by electrospray ionization mass spectrometry (ESI-MS). This includes a specially designed flow system, which allows continuous online mixing, derivatization, extraction, separation, and quantitative detection within ca. 3 min. For electrospray ionization of formaldehyde, it is first online-derivatized by 2,4-dinitrophenyl hydrazine to form the easily ionizable 2,4-dinitrophenyl hydrazone. Then, both formic acid and derivatized formaldehyde are online extracted into an immiscible organic phase, which, after separation from the aqueous phase, is piped to the ESI-MS for analysis. This strategy ensures complete removal of the highly corrosive sulfuric acid from the analyte and allows the liquid-phase methanol oxidation reaction (MOR) products (formaldehyde and formic acid) to be quantitatively detected by ESI-MS. Finally, the potential of this method for online analysis in electroanalysis and electrocatalysis is discussed.
我们描述了一种新的方法和设置，用于通过电喷雾电离质谱（ESI-MS）对酸性水溶液中液相甲醇氧化产物进行定量在线分析。这包括一个专门设计的流系统，允许在大约 3 分钟内连续在线混合、衍生化、提取、分离和定量检测。对于甲醛的电喷雾电离，首先通过 2,4-二硝基苯肼在线衍生化，形成易离子化的 2,4-二硝基苯腙。然后，甲酸和衍生化的甲醛都在线提取到不混溶的有机相中，在与水相分离后，将其输送到 ESI-MS 进行分析。该策略确保将腐蚀性很强的硫酸从分析物中完全去除，并允许通过 ESI-MS 对液相甲醇氧化反应（MOR）产物（甲醛和甲酸）进行定量检测。最后，讨论了该方法在电分析和电催化中的在线分析潜力。
