The degradation of lithospermic acid B (LAB) was investigated as a function of buffer concentration, pH and temperature. Stability tests were performed using a stability-indicating high-performance liquid chromatography (HPLC) with UV-vis detection. The degradation followed pseudo-first-order kinetics under all experimental conditions. The maximum stability of LAB was observed at pH 2.0. The logk(pH)-pH profile described by specific acid-base catalysis and water molecules agreed with the experimental results. The overall degradation rate constant as a function of the temperature under the given conditions obeyed the Arrhenius equation. The chemical fate of LAB in mild acidic solution was investigated, and nine degradation products were detected and tentatively identified by LC-MS analysis. The primary degradation pathway involving the cleavage of ester bond and ring-opened of benzofuran in the LAB are proposed.

中文翻译：

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紫精酸B在水溶液中的降解动力学和机理。

研究了作为缓冲液浓度、pH 值和温度的函数的紫精酸 B (LAB) 的降解。使用具有紫外-可见检测的稳定性指示高效液相色谱 (HPLC) 进行稳定性测试。在所有实验条件下，降解遵循准一级动力学。在 pH 2.0 时观察到 LAB 的最大稳定性。由特定酸碱催化和水分子描述的logk(pH)-pH曲线与实验结果一致。在给定条件下，作为温度函数的总降解速率常数遵循阿伦尼乌斯方程。研究了 LAB 在弱酸性溶液中的化学归宿，通过 LC-MS 分析检测并初步鉴定了 9 种降解产物。