固相萃取-超高效液相色谱法同时测定乳制品中6种有机酸

Determination of organic acids in diary products by solid phase extraction-ultra performance liquid chromatography

建立了固相萃取-超高效液相色谱（UPLC）同时测定乳制品中苹果酸、酒石酸、乳酸、乙酸、柠檬酸、富马酸等6种有机酸的分析方法。样品用体积分数1％氨水溶液提取，调节至中性后经MAX柱净化，用AcquityUPLCHSST3色谱柱（2．1illnl×100mnl，1．8μm）分离，以乙腈和0．02mol／LKH2P04缓冲溶液（pH2．0）作为流动相进行梯度洗脱，二极管阵列检测器检测。6种有机酸在其相应范围内（0．05～5000mg／L）线性关系良好（r2≥0．999），方法的定量限（信噪比为10）为0．05～25．0mg／kg，3个不同水平的添加浓度回收率为80．1％～103．2％，相对标准偏差（n=8）在1．9％～11％之间。方法适合于乳制品中6种有机酸的同时检测。

A method for the determination of malic acid, tartaric acid , lactic acid, acetic acid, citric /tcid and fumaric acid in diary products has been developed by ultra performance liquid chromatography （UPLC）. After extracted by 1% ammonium hydroxide（V/V） and purified by a MAX cartridge, the samples were loaded onto an Acquity UPLC HSS T3 column （ 2.1 mm × 100 mm, 1.8 μm ） and separated with the mobile phase consisting of acetonitrile - 0.02 mol/L potassium dihydrogen phosphate （ pH 2.0） in a gradient elution mode with a PDA detector. The calibration curves showed a good linearity in the range of 0.05 - 5000 mg/L, and the correlation coefficients （ r2） were higher than 0. 999. The limits of quantification （ LOQs, S/N = 10） of organic acids were 0.05 - 25.0 mg/kg. Under three spiked levels, the recoveries of organic acids in diary products ranged from 61.9% to 103.2% , with the relative standard deviations （RSDs） of 1.9% - 11%.