将4种溶质(以10∶10∶1∶1质量比混合的DPPC、胆固醇、DPPG及DPPE)的混合物22 mg,溶于4 mL氯仿-异丙醚-甲醇(6+6+1)混合溶剂中。向此溶液中加入0.15 mol·L-1亚铁氰化钾溶液1 mL,于45 ℃超声涡旋5 min使其包埋于脂质体中。将此脂质体包埋的亚铁氰化钾溶液1 mL,通过戊二醛(0.7+99.3)溶液2 mL的作用,与200 μL 2,4-D免抗体溶液(10.53 g·L-1)交联。另将自制MWNT′s修饰的石墨电极插入0.05 mol·L-1脂质体-抗体-吡咯溶液中,用循环伏安法在0~0.75 V电位区间扫描10次,扫描速率为50 mV·s-1。由此制成的免疫传感器应用于测定尿样中2,4-D含量,其线性范围为0.05~2.5 mg·L-1之间,检出限(3S/N)为15.4 μg·L-1。

To prepare the immunosensor, tiposome was prepared, by dissolveing 22 mg of the mixture of solutes of DPPC, cholesterol, DPPG and DPPE (mixed in the mass ratio of 10 to 10 to 1 to 1) in 4 mL of a mixed solvent of chloroform, isopropylether and methanol (6+6+1 by volume). Potassium ferrocyanide solution (0.15 mol·L-1, 1 mL) was added to the liposome and encapsulated by swirling ultrasonically for 5 min at 45 ℃. Then the liposome encapsulated K4Fe(CN)6 solution (1 mL) was crosslinked with 2,4-D-rabbit antibody (10.53 g·L-1, 200 μL) through the action of glutaric dialdehyde solution (0.7+99.3, 2 mL). A self-prepared MWNT′s modified graphite electrode was dipped into 0.05 mol·L-1 liposome-antibody-pyrrole solution, and polymerized by cyclic voltammetry for 10 times in the potential range of 0-0.75 V at the rate of 50 mV·s-1. This immunosensor was used for rapid determination of 2,4-D in urine. Linearity was obtained in the range of 0.05-2.5 mg·L-1, and the detection limits (3S/N) found was 15.4 μg·L-1.