百里酚分光光度法测定发酵液中L-精氨酸含量

Determination of L-Arginine Concent in Fermentation Liquor by Thymol-Spectrophotometric Method

目的:建立定量检测发酵液中L-精氨酸含量的方法。方法:以百里酚的次溴酸钠溶液为显色剂,用分光光度计比色测定。结果:百里酚分光光度法检测L-精氨酸的最佳条件为:样品稀释液5.0mL,依次加入0.03%百里酚溶液2.0mL,0.7%次溴酸钠溶液1.0mL,摇匀,30s内加入40%尿素溶液1.0mL,冰水浴中显色2min,测定OD470nm。该方法的检出限为2.0μg/mL,摩尔吸光系数ε为6.8×103L/(mol·cm),回收率98.8%～101.2%,发酵液样品测定的相对标准偏差0.23%～0.59%。结论:该方法简便、快速、准确可靠,适合用于发酵液中L-精氨酸含量的定量检测。

Objective：To make a simple method for determination of L-arginine in fermentation liquor. Methods：Using thymol-sodium hypobromite as chromogenic reagent,a spectrophotometric method was studied. Results：The optimal conditions of L-arginine determination were：2.0 mL of 0.03% thymol,1.0 mL of 0.7% sodium hypobromite was added in 5.0 mL of appropriately diluted sample solution sequentially, the test tube was energetically shaken,and then 1.0 mL of 40% urea was added within 30 seconds,the mixture kept in ice water bath for 2 minutes,finally,its OD value was measured at 470 nm. The determination limit of the method was 2 μg/mL,its molar absorptivity ε was 6.8×103 L/（mol·cm）,its recoveries were 98.8%～101.2%,and RSD of fermentation liquor sample determination were 0.23%～0.59%. Conclusion：The method presented in this paper is simple、fast、accurate and reliable,and it is suitable for the quantitative determination of L-arginine content in fermentation liquor.