高效毛细管电泳法测定牛奶和奶粉中残留的三聚氰胺

建立了牛奶和奶粉中三聚氰胺的高效毛细管电泳-二极管阵列检测器(HPCE-DAD)检测方法。使用长度58.5 cm、内径75 μm的毛细管柱，分离电压25 kV，进样量3.5 kPa (35 mbar)×8 s，分离温度25 ℃，缓冲溶液20 mmol/L 柠檬酸-40 mmol/L 磷酸氢二钠(pH 2.6)，检测波长232 nm。分析物在1~100 mg/L 范围内线性良好，r2>0.997；牛奶和奶粉的定量限分别为0.5 mg/kg和1.0 mg/kg。在添加水平为定量限浓度至50 mg/kg时的回收率为72.2%~97.3%，相对标准偏差为2.1%~3.9%。

Determination of melamine in milk and milk powder by high performance capillary electrophoresis

A high performance capillary electrophoresis (HPCE) method has been established for the separation of melamine in milk and milk powder. The separation was carried out on a fused-silica uncoated capillary column （58.5 cm×75 μm）. The sample was injected by hydrodynamic injection (3.5 kPa (35 mbar)×8 s) at a temperature of 25 ℃. The analysis was completed in about 6 min in 40 mmol/L Na2HPO4-20 mmol/L citric acid buffer (pH 2.6) at 25 kV of separation voltage and 232 nm of detection wavelength. The linear range of melamine was 1-100 mg/kg, and the correlation coefficient was higher than 0.997. The limits of quantification (LOQs) in milk and milk powder were 0.5 mg/kg and 1.0 mg/kg, respectively. The average recoveries were in the range of 72.2%-97.3% in the spiked range of the concentration of LOQs and 50 mg/kg, and the relative standard deviations were between 2.1% and 3.9%.