分子印迹固相萃取-高效液相色谱法测定猪肉中红霉素残留

采用沉淀聚合法，以红霉素（erythromycin，ERY）为模板，甲基丙烯酸（methacrylic acid，MAA）为功能单体，乙二醇二甲基丙烯酸酯（ethyleneglycoldimethacrylate，EGDMA）为交联剂，甲醇/乙腈（1:4，v/v）为致孔剂制备了ERY分子印迹聚合物（molecularly imprinted polymers，MIPs）。通过扫描电镜、平衡吸附实验等对制备的印迹和非印迹聚合物进行表征和测定，结果表明所制备的MIPs对ERY具有特异性吸附作用。Scatchard分析证明MIPs对ERY的吸附存在两类不同结合位点，最大表观结合量（Q_max）和平衡解离常数（K_d）分别为Q_max1=45.24 mg/g，K_d1=0.028 g/L； Q_max2=87.53 mg/g，K_d2=0.20 g/L。以制备的MIPs为吸附剂的分子印迹固相萃取柱，结合高效液相色谱法能够快速检测猪肉样品中的ERY残留，线性范围为0.5~50 mg/L（r²=0.9994），检出限（S/N=3）为0.2 mg/kg。猪肉样品中不同添加水平下ERY的加标回收率为95.2%~104.2%，相对标准偏差（RSD）小于5%。该方法选择性好，灵敏、可靠，可用于猪肉等复杂食品样本中ERY残留的检测。

Determination of erythromycin residue in pork samples using molecularly imprinted solid phase extraction coupled with high performance liquid chromatography

Molecularly imprinted polymers (MIPs) for erythromycin (ERY) were prepared by precipitation polymerization, using ERY as template molecule, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linker and methanol/acetonitrile (1:4, v/v) as porogens. The characterization of the prepared MIPs and non-imprinted polymers (NIPs) were evaluated by scanning electron microscope (SEM) and equilibrium adsorption experiment. The results showed that the MIPs possessed the specific adsorptivity toward ERY. Scatchard analysis revealed that the apparent maximum binding capacity (Q_max) and the dissociation content (K_d) to ERY were as follows: Q_max1=45.24 mg/g, K_d1=0.028 g/L; Q_max2=87.53 mg/g, K_d2=0.20 g/L. Using the prepared MIPs as selective adsorbent, the proposed molecularly imprinted solid phase extraction (MISPE) coupled with high performance liquid chromatography (HPLC) was successfully applied to determine ERY residue in pork samples. A linear correlation was obtained over a range of 0.5-50 mg/L (r²=0.9994), and the limit of detection was 0.2 mg/kg (S/N=3). The spiked recoveries of ERY were 95.2%-104.2% with the relative standard deviations (RSDs) of less than 5%. The proposed method is selective, sensitive and reliable for the analysis of ERY residue in pork samples.