中文摘要：

采用电喷雾串联质谱（ESI—MS^n）技术，结合氢／氘交换方法，研究了L-抗坏血酸在正、负离子模式下的质谱行为．实验表明，电喷雾质谱能够方便地观测到实验条件下 L-抗坏血酸的特征裂解方式和相应碎片；实验发现毛细管温度对，L-抗坏血酸的裂解方式产生显著的影响，从不同毛细管温度下的相应质谱信号强度变化能观察到L-抗坏血酸及其降解产物的热稳定性差异．因此，根据串联质谱所观测到的L-抗坏血酸特征碎片离子，提出了L-抗坏血酸的结构变化及其降解反应的可能机理和基本规律，为现代质谱技术快速测定复杂基体样品中的痕量抗坏血酸奠定了实验基础．

英文摘要：

The electrospray ionization tandem mass spectrometry （ESI-MSn） of L-ascorbic acid was studied using both positive and negative ion detection modes. Under the electrospray ionization conditions, L-ascorbic acid dissociated readily to form various characteristic fragments, which provided interesting insights into the organic chemistry of ascorbic acid. The effect of capillary temperature on fragmentation of L-ascorbic acid was experimentally investigated using multiple stage tandem electrospray ionization mass spectrometry. The mechanism of the degradation of L-ascorbic acid was discussed in detail based on the experimental collision-induced dissociation data recorded in these experiments, and was confirmed by the hydrogen/deuterium exchange experiments.