酸奶中乳酸含量测定的毛细管区带电泳方法研究

建立了测定酸奶中乳酸含量的间接紫外检测毛细管区带电泳方法。在未涂渍的石英毛细管(内径75μm,有效长度50cm)中,以10.0mmol/L的2,6-吡啶二羧酸-0.5mmol/L十六烷基三甲基溴化铵(pH3.5)为运行电解质,检测波长214nm,在-15kV分离电压下酸奶中乳酸6min内能得到分析。方法重现性好,迁移时间和峰面积的相对标准偏差分别在1.0%和2.0%以内。在相应的浓度范围内,峰面积与样品浓度之间呈现良好的线性关系。该法简单、快速、灵敏度高,为测定酸奶中乳酸含量提供了一种高效、快速、简便的方法。

Study on Rapid Determination of Lactic Acid in Yoghurt by Capillary Electro-phoresis Method

A capillary electrophoresis method with indirect UV detection at 214nm for the determination of lactic acid in yoghurtwas established. By using an uncoated silica capillary (75μm i.d., 50cm efficient length) and 10.0mmol/L 2,6-pyridinedicarboxylate-0.5mmol/L cetyltrimethylammonium bromide (CTAB) at pH3.5 as carrier electrolyte, lactic acid in yoghurt was sufficientlyseparated within 6min at an applied voltage of -15kV (anode at detector). Quantification by the peak area method allowedreproducible determination of the analyte at a concentration range of 5～100μg/ml. The relative standard deviations for migrationtime and peak area were less than 1.0% and 2.0% respectively. The capillary electrophoresis method was characterized by itssimplicity, rapidity, and reproducibility, and should be useful for the determination of lactic acid in yoghurt.