SPE-HPLC测定土霉素菌渣中土霉素的残留效价

Determination of oxytetracycline in oxytetracycline bacterial residue by SPE-HPLC

使用固相萃取－高效液相色谱法检测土霉素菌渣中土霉素的残留效价，样品用甲醇／冰乙酸／0．5mol／L NaCl（V／V／V＝5／4／2）提取，经Waters Sep－Pak C18固相萃取柱净化，用高效液相色谱仪进行检测．色谱柱为C18柱，流动相为乙腈：0．02 mol／L磷酸二氢钠缓冲溶液（ pH＝2．5，1 L溶液含0．48gNa2EDTA）25∶75（V∶V），检测波长为354 nm，流速为1．0 mL／min，进样量为10μL，柱温为30＆#176;C．结果表明，土霉素的方法检出限为0．032 mg／L，在不同加标量（1、2、5 mg／kg）下，回收率可达89．2％～97．4％，相对标准偏差为1．6％～2．4％（n＝6），标准曲线的线性关系良好．该方法操作方便，灵敏度高且检测成本较低，可广泛用于土霉素菌渣的检测，并且为土霉素菌渣资源化提供基础数据．

A method was developed for the determination of oxytetracycline in oxytetracycline bacterial residue by high performance liquid chromatography coupled with solid phase extrac-tion.The oxytetracycline was extracted with the mixture of methanol, acetic acid and 0.5 mol/L NaCl with the volume ratio of 5∶4∶2, and purified by a hydrophilic lipophilic balance （ HLB） solid-phase extraction cartridge.The extract was then analyzed by a high-per-formance liquid chromatography （ HPLC） instrument and a C18 column.The mobile phase was acetonitrile： 0.02 mol/L NaH2 PO4 （ pH =2.5, 1 L solution containing 0.48g Na2 EDTA） with the volume ratio of 25∶75.The detection wavelength was 354 nm.The flow rate was 1.0 mL/min, and the injection volume was 10 μL.The temperature was 30 ＆#176;C. The results showed that the limit of detection for OTC was 0.032 mg/L, and the recovery of OTC in oxytetracycline bacterial residue was 89.2%~97.4%at the spiked levels from 1 to 5 mg/kg （ RSDs ranged from 1 .6%~2 .4%, n =6 ） , and the standard curve had an excel-lent linear.The method has advantages of easy operation, high accuracy and low cost of de-tection.The method could widely applied to determine the oxytetracycline in oxytetracycline bacterial residue, meanwhile provide basic data for its resource utilization.