Derivatization reagents based on azobenzene containing different N-hydroxysuccinimidyl moieties– AzoB (carbamate) and AzoC (ester) – are proposed for the LC-ESI-MS analysis of free amino acids in fermented beverages and juices. A dual comparison between LC-MS/MS in positive and negative ESI modes in dynamic Multiple Reaction Monitoring (dMRM) and Neutral Loss Scan was investigated. The results indicate that the studied carbamate derivatization reagent, AzoB, can be employed for targeted analysis (MS/MS) but also for non-targeted analysis of derivatized amino acids thanks to its constant neutral loss (223 Da) that is the same in both ionisation modes. For amines, precursor ion scan can be used as identification tool. The derivatization properties of AzoB and AzoC were compared against other derivatization reagents, and they showed advantages such as fast derivatization reaction and good reactivity with secondary amines. AzoC also displayed a disadvantage –side products were formed that affect the quantitation. Free amino acids profile of Kvass (a fermented beverage from eastern Europe) was determined for first time, proline was found to be the most abundant amino acid.

基于含有不同 N-羟基琥珀酰亚胺基部分的偶氮苯的衍生试剂——AzoB（氨基甲酸酯）和 AzoC（酯）——被提议用于发酵饮料和果汁中游离氨基酸的 LC-ESI-MS 分析。研究了动态多反应监测 (dMRM) 和中性丢失扫描中正负 ESI 模式下 LC-MS/MS 之间的双重比较。结果表明，所研究的氨基甲酸酯衍生化试剂 AzoB 可用于靶向分析 (MS/MS)，但由于其恒定的中性损失 (223 Da) 在两者中相同，也可用于衍生化氨基酸的非靶向分析电离模式。对于胺类，前体离子扫描可用作鉴定工具。将 AzoB 和 AzoC 的衍生化特性与其他衍生化试剂进行了比较，并表现出衍生化反应快、与仲胺反应性好等优点。AzoC 也有一个缺点——形成了影响定量的副产物。首次测定格瓦斯（一种来自东欧的发酵饮料）的游离氨基酸谱，发现脯氨酸是含量最高的氨基酸。