超声萃取-高效液相色谱法同时测定奶粉中4 种雌激素类残留

建立超声波萃取-高效液相色谱法同时测定奶粉中炔雌醇、己烯雌酚、壬基酚、苯甲酸雌二醇残留量的方法。样品以乙腈超声萃取、离心，提取液浓缩后经0.45 μm滤膜过滤，进高效液相色谱仪分析。研究萃取溶剂、萃取时间及离心时间对萃取效率的影响，确立色谱检测条件。结果表明，乙腈和0.043 mol/L磷酸二氢钠缓冲液（用磷酸调至pH值到5）为流动相，梯度洗脱，流速1 mL/min，柱温30 ℃，检测波长224 nm。方法的检出限为3～20 μg/kg，4 种组分得到良好分离，加标回收率在80.2%～101.0%之间，工作曲线的相关系数在0.992 4～0.999 7之间，相对标准偏差在0.95%～2.04%之间（n=3），方法快速、灵敏度高、分离效果好，样品处理简单、无杂质干扰，能够满足奶粉中雌激素分析的需要。

Simultaneous Determination of Four Estrogen Residues in Powdered Milk Using Ultrasonic Extraction-HPLC

A method was developed for the simultaneous determination of residues of ethinyl estradiol, diethylstilbestrol,
4-nonylphenol and estradiol benzoate in powdered milk by high performance liquid chromatograph (HPLC) after ultrasonic
extraction. Samples were ultrasonically extracted with acetonitrile and after centrifugation of the extract, the supernatant was
concentrated and filtrated through a 0.45 μm filter before analysis by HPLC. Extraction solvent, extraction and centrifugation
time, and HPLC conditions were optimized. The analysis was conducted by using gradient elution with acetonitrile-0.043 mol/L
NaH2PO4 buffer as the mobile phase. Under the optimized conditions, the four estrogens were separated well, and the
proposed method exhibited good reproducibility (0.95%–2.04%) and recovery (80.2%–101.0%). The calibration curves
were linear with correlation coefficient ranging from 0.992 4 to 0.999 7. The limit of detection of the method ranged from
3 to 20 μg/kg. This method proved to be rapid, sensitive and simple without interference of impurities and be able to meet
the analytical requirements for residues of these four estrogens in milk powder.