柱后衍生-荧光检测高效液相色谱法快速测定鲜牛奶中链霉素残留量

Post column derivatization liquid chromatographic method for determination of streptomycin residues in milk

牛奶样品经磷酸溶液提取,提取液用苯磺酸阳离子交换柱和C18固相萃取柱净化,链霉素残留液用甲醇从C18固相萃取柱上洗脱,经旋转蒸发器减压蒸干,残渣用0 01mol/L庚烷磺酸钠溶液溶解,用柱后衍生高效液相色谱荧光检测器在激发波长263nm和发射波长435nm测定.方法线性范围为0 01～0 10mg/kg;在0 01～0 10mg/kg范围,三个添加水平的回收率为78 3%～80 2%,变异系数(CV)为7 4%～12 4%,方法检出限为0 005mg/kg.

Milk samples are dissolved with phosphoric acid(pH=2),and the solutions are cleaned up by aromatic suphonic cation exchange cartridge and C_(18)SPE cartridge.While the streptomycin residues are eluted off via C_(18) SPE cartridge with methanol and evaporate to dryness on rotary evaporator, and the residues are dissolved in 0.01 mol/L (1-heptane) sulphonic acid slution(pH=3.3) for determination by postcolumn derivatizationliquid chromatography fluorescence detection with an excitation wavelength of 263 nm and an emission wavelength of 435 nm.The linear range of streptomycin for the said method is 0.01～0.10 mg/kg,in which the recoveries at four fortification levels are 78.3%～80.2%,coefficients of variation(CV) 7.4%～12.4%,limit of detection for the methodis 0.005 mg/kg.