高效液相色谱法测定奶粉和液态奶中的三聚氰胺

建立了奶粉和液态奶中三聚氰胺的高效液相色谱（HPLC）检测方法。经阳离子交换固相萃取柱净化后的样品采用HPLC测定。优化的色谱条件：C18柱（4.6 mm ×200 mm，5 μm），流动相为乙腈-0.01 mol/L庚烷磺酸钠（pH 3.3）（体积比为10∶90），流速为1.0 mL/min，检测波长为236 nm，柱温为40 ℃，进样量为20 μL。方法的线性范围为1~500 mg/L，检出限为0.2 mg/kg （S/N=3），定量限为1 mg/kg （S/N=15），回收率为81.4%~83.7%，相对标准偏差为3.3%~8.5%（n=6）。

Determination of melamine in milk powder and milk by high performance liquid chromatography

The analytical method of melamine in milk and milk powder by high performance liquid chromatography (HPLC) was established. The sample was purified by a cation exchange solid-phase extraction column, separated on a Diamonsil C18 column (4.6 mm×200 mm, 5 μm) with acetonitrile-0.01 mol/L sodium heptanesulfonate (pH 3.3) (10∶90, v/v) as mobile phase at a flow rate of 1.0 mL/min, and determined by a photodiode array detector. A linear calibration curve was obtained in the concentration range of 1-500 mg/L. The qualification limit was 0.2 mg/kg, and the quantification limit was 1 mg/kg. The recovery was 81.4%-83.7%.