Rapid Determination of Free Amino Acids in Milk by Microchip Electrophoresis Coupled with Laser-induced Fluorescence Detection

• Published in: Chinese journal of chemistry Vol. 30; no. 10; pp. 2517 - 2521
• Main Author: 吴敏 成双 李刚 汪志芳 王清江 何品刚 方禹之
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2012; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Amino acids; Electrophoresis; free amino acids; laser-induced fluorescence detection; microchip electrophoresis; Milk; 分离电压; 微流控芯片电泳; 微芯片电泳; 快速测定; 游离氨基酸; 激光诱导荧光检测; 牛奶样品; 琥珀酰亚胺
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.201200446

A simple and sensitive method for determination of free amino acids in milk by microchip electrophoresis （MCE） coupled with laser-induced fluorescence （LIF） detection was developed. Seven kinds of standard amino ac- ids were derivated with sulfoindocyanine succinimidyl ester （Cy5） and then perfectly measured by MCE-LIF within 150 s. The parameters of MCE separation were carefully investigated to obtain the optimal conditions： 100 mmolo L^-1 sodium borate solution （pH 10.0） as running buffer solution, 0.8 kV as injection voltage, 2.2 kV as separation voltage etc. The linear range of the detection of amino acids was from 0.01 μmol·L^-1 to 1.0 μmol·L^-1 and the detection limit was as low as about 1.0 μmol·L^-1. This MCE-LIF method was applied to the measurements of free amino acids in actual milk samples and satisfactory experimental results were achieved.