Investigation of photochemical reaction products of glucose formed during direct UV detection in CE
Investigation of photochemical reaction products of glucose formed during direct UV detection in CE
复制标题
研究 CE 直接紫外检测过程中形成的葡萄糖光化学反应产物
作者：
T. Schmid;M. Himmelsbach;W. Buchberger
在 CE 中，由于分离毛细管检测窗口中的光化学反应导致形成 UV 吸收物质，糖类可以直接进行 UV 检测。本研究采用允许长时间毛细管内照射并随后进行 UV 和 MS 检测的 CE 方法，可以识别几种葡萄糖的反应产物。其中包括迄今为止未知的在直接紫外检测过程中形成的紫外吸收物质，其化学式为C4H6O2、C5H6O4、C5H8O3和C6H8O5。对辐照时间影响的研究揭示了这些反应产物之间的差异，表明不同的反应机制，特别是对于最小的产物。通过使用同位素标记的底物进行实验来确定转化为特定反应产物的葡萄糖部分，可以获得更详细的信息。此外，根据离线辐照葡萄糖溶液的 HPLC-MS/MS 测量建议了反应产物的结构式，该测量揭示了羧酸或醛基等官能团的存在。
In CE, saccharides are accessible to direct UV detection due to a photochemical reaction in the detection window of the separation capillary resulting in the formation of UV absorbing substances. Employing a CE method that allows long in‐capillary irradiation with subsequent UV and MS detection, the present study could identify several reaction products of glucose. Among these were UV absorbing substances so far unknown to be formed during direct UV detection with the chemical formulas C4H6O2, C5H6O4, C5H8O3, and C6H8O5. Investigations of the impact of the irradiation time revealed differences between these reaction products suggesting differing reaction mechanisms especially for the smallest products. More detailed information could be obtained by experiments with isotope‐labeled substrates performed to determine the parts of glucose that are converted to the particular reaction products. In addition, structural formulas for the reaction products were suggested based on HPLC‐MS/MS measurements of off‐line irradiated glucose solutions which revealed the existence of functional groups such as carboxylic acid or aldehyde groups.