应用气相色谱法分析有机酸,大多数情况下是先将有机酸甲酯化,然后再进行色谱测定。气相色谱法中常用的甲酯化方法有BF_3/CH_3OH法和HCl/CH_3OH法,对于使用对甲苯磺酸/甲醇（PTSA/CH_3OH）作为甲酯化试剂,文献[3]已作过初步探索。本文着重讨论该试剂和其他几种常用试剂的比较。实验结果表明:该试剂对于某些芳羧酸的甲酯化反应,明显优于上述两种常用的方法。 Organic acids are analyzed by gas chromatography. In most cases, organic acids are first methyl esterified and then subjected to chromatographic determination. The commonly used methyl esterification methods in the gas chromatography are the BF_3 / CH_3OH method and the HCl / CH_3OH method. For the use of p-toluenesulfonic acid / methanol (PTSA / CH_3OH) as the methyl esterification reagent, literature [3] has been explored. This article focuses on the comparison of this reagent with several other commonly used reagents. The experimental results show that this reagent is obviously superior to the two commonly used methods for the methyl esterification of some aromatic carboxylic acids.