L-异亮氨酸在紫外光区无吸收峰，需将其进行衍生后才能测定． 通过对比两种柱前衍生方法，建立高效液相色谱法柱前衍生检测L-异亮氨酸质量分数的方法． OPA 自动衍生法检测耗时15 min，R =1，加标回收率99% ～ 100． 1%，RSD ＜ 1． 0%; PITC 手动衍生法检测耗时30 min，加标回收率96% ～ 98%，RSD ＜ 1%． OPA 自动衍生法在检测的时效性和准确性方面均具有明显优势，可用来高效地检测L-异亮氨酸的质量分数，在生物发酵、饲料添加剂、食品添加剂和制药等领域具有较高的应用价值．

L-Isoleucine has no absorption in the ultraviolet ( UV) region and needs to be derivatized before determination by UV detector． The aim of this work is to compare the two pre-column derivatization methods: OPA automatic derivatization and PITC manual derivatization，and establish an efficient method for the determination of L-isoleucine content by high performance liquid chromatography． The total detection time with OPA automatic derivatization method took 15 minutes with Ｒ-value of 1，and the recoveries were from 99% to 100． 1% with ＲSD ＜ 1%． The PITC manual derivatization took 30 min， with the recovery rate of 96% to 98% ( ＲSD ＜ 1%) ． OPA automatic derivatization exhibited obvious advantages in the detection timeliness and accuracy，which can be used to efficiently detect L-isoleucine content． It has high application value in microbial fermentation，feed additives，food additives and pharmaceuticals．