First, multi-wall carbon nanotubes(MWCNs) were modified on the screen printed electrode (SPE), and then molecularly imprinted membrane(MIM) and non-imprinted membrane(NIM) were directly synthesized on the modified SPE by using the in-situ thermal polymerization techniques, respectively. A conductometric sensor for the detection of ractopamine was assembled by connecting the SPE modified with MWCNs-MIM and the other one coated with MWCNs-NIM to a conductometer through an electrode slot. Standard calibration curve was established and the determination of ractopamine in pig urine samples also was performed based on this sensor. Superficial characteristic of MIM and NIM was investigated using scanning electron microscope (SEM). The results showed that there were number of imprinted micro-pores on the surface of MIM. The sensor showed high selectivity and specificity towards the target ractopamine. The response of the sensor to concentration of ractopamine displayed a linear correlation over a range from 0. 33 to 8. 0 mg/L with a detection limit of 0. 033 mg/L. The recoveries were 91% - 98% based on pig urine samples for the determination of ractopamine on sites.%采用原位热聚合技术,分别以多壁碳纳米管(MWCNs)和分子印迹膜(MIM)修饰丝网印刷电极(SPE),与多壁碳纳米管和非分子印迹膜(NIM)修饰的丝网印刷电极组合在一起,并将其组合的丝网印刷电极通过电极插口与便携式电导仪相连接,组装成检测莱克多巴胺残留的电导型传感器,优化检测条件,并建立了检测莱克多巴胺的标准曲线,测试了实际猪尿样中莱克多巴胺的含量.通过扫描电镜分析了该分子印迹膜的表征结构.结果表明,在莱克多巴胺分子印迹膜表面形成了大量印迹微孔.本传感器装置检测莱克多巴胺具有很高的灵敏度和特异性,检出限为0.033 mg/L,线性范围为0.33～8.0 mg/L,基于猪尿样的检测回收率达到91％～98％,可实现现场快速检测.
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