检测水中有机磷农药的酶传感器

采用丝网印刷技术制作厚膜型电极,通过交联法将乙酰胆碱酯酶固定在电极上,开发快速检测水中有机磷农药的酶传感器.采用循环伏安法对电极所做的检测结果表明电极彼此间的差异在10%以内,具有较好的一致性.通过在交联剂、酶和底物等方面优化传感器的工作参数,确定了戊二醛、酶和底物的浓度分别为0.2%、0.5 mg/mL和10 mmol/L时,传感器响应最好.在交联固定酶的情况下,根据酶活受到有机磷抑制的原理,采用时间-电流法对特丁硫磷和对硫磷进行了检测.结果表明:这2种有机磷的检测限都可以达到1 ng/mL,线性区间1～10 000ng/mL.在物理吸附固定酶的情况下,采用循环伏安法对特丁硫磷进行了检测.结果表明:采用循环伏安法检测的灵敏度比采用时间-电流法的灵敏度要高.

Detecting Organophosphorus Pesticide in Water Environment Using an Enzyme Biosensor

Based on a screen printed carbon electrode which contained a sensitive film prepared by crosslinking acetylcholine esterase (AChE) with glutaraldehyde on the surface of working electrode, an amperometric enzyme biosensor was taken on the determination of organophosphorus (OP) pesticide in water environment. Cyclic voltammetry was applied to assess the coherence of prepared screen printed electrodes. The results show that the variation is less than 10%. The sensor sensitivity was optimized with respect to content of enzyme, crosslinker and substrate. The best sensitivity is obtained using 0.2% of glutaraldehyde, 0.5mg/mL of AChE and 10mmol/L of acetylthiocholine chloride (ATChCl). Amperometric i-t curve was conducted to detect the decrease rate of the current after the addition of two kind of OPs (terbufos and parathion), respectively. The detection limit for two kind of OPs are found to be 1ng/mL with the linear range 1ng/mL~10000ng/mL. Cyclic voltammetry was conducted to detect parathion on the sensors which immobilized AChE by physical adsorption. The results show that it can achieve a better sensitivity than amperometric i-t curve.