Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
J Am Soc Mass Spectrom. 2010 May;21(5):773-84. doi: 10.1016/j.jasms.2009.11.008. Epub 2009 Dec 4.
A mass spectrometric method has been developed for the identification of carbonyl and hydroxyl functional groups, as well as for counting the functional groups, in previously unknown protonated bifunctional oxygen-containing analytes. This method utilizes solution reduction before mass spectrometric analysis to convert the carbonyl groups to hydroxyl groups. Gas-phase ion-molecule reactions of the protonated reduced analytes with neutral trimethylborate (TMB) in a FT-ICR mass spectrometer give diagnostic product ions. The reaction sequence likely involves three consecutive steps, proton abstraction from the protonated analyte by TMB, addition of the neutral analyte to the boron reagent, and elimination of a neutral methanol molecule. The number of methanol molecules eliminated upon reactions with TMB reveals the number of hydroxyl groups in the analyte. Comparison of the reactions of the original and reduced analytes reveals the presence and number of carbonyl and hydroxyl groups in the analyte.
已经开发出一种质谱方法，用于鉴定先前未知的质子化双官能含氧分析物中的羰基和羟基官能团，并用于计算官能团的数量。该方法在质谱分析前利用溶液还原将羰基转化为羟基。在傅里叶变换离子回旋共振质谱仪中，质子化还原分析物与中性三甲基硼酸（TMB）的气相离子-分子反应产生诊断产物离子。反应序列可能涉及三个连续的步骤，即 TMB 从质子化分析物中提取质子、中性分析物与硼试剂加成以及中性甲醇分子的消除。与 TMB 反应时消除的甲醇分子数揭示了分析物中羟基的数量。比较原始和还原分析物的反应揭示了分析物中羰基和羟基的存在和数量。
