基于循环伏安扫描(CV)的电化学沉积方法制备出多孔性纳米簇状结构铜膜,结合采用微机电系统(Microelectro mechanical systems,MEMS)技术制备的微电极芯片,研制出用于NO3^-检测的安培型微传感器。考察该微传感器对N03的响应性能,在6.25~300μmol/L浓度范围内,灵敏度为0.0526μA/(μmol/L),线性度99.93%;在300~3500μmol/L浓度范围内,灵敏度为0.0353μA/(μmol/L),线性度99.18%。与文献报道相比,该传感器表现出更高的灵敏度。考察水体中常见的NO2,CI^-,HPO4^3-/PO4^2-,SO4^2-,HCO3^-/CO3^2-,Na^+和Ka^+等离子对该传感器的干扰性能,传感器表现出较好的抗干扰性能。采用该微传感器对实际水样进行测试,测试结果与具有权威资质的测试公司的测试结果之间具有一定的相关性。实验结果表明,采用循环伏安沉积方法在微电檄表面制备的纳米簇状结构的铜敏感膜,比表面积大,催化活性高,对NO3^-表现出了很好的敏感特性和选择性,适用于对微量NO3^-的检测。
A method based on cyclic voltammetry to modify the sensing surface to be macroporous copper nano-clusters was developed and for the detection of nitrate in a micro amperometric electrode, which was an electrochemical system composed of two-electrode system and fabricated based on Micro-Electro-Mechanical Systems (MEMS) technology. The experiment results demonstrate that this method as a controllable and convenient manipulation can effectively modify the surface of the working electrode for further nitrate determination more rapidly with less consumption of reagent, and enhance the sensitivity of the electrode. The experimental results reveal that under the optimal experimental conditions microelectrode surface modified by cyclic voltammetry electrodeposition was macroporous and had a larger effective surface area, which shows marked sensitivity and selectivity for nitrate ions within the concentration range from 6. 25 to 3500 μmol/L(6. 25-300 μmol/L yielded straight lines. y1=-0.0526x-3. 905, R1^2= 0. 9993, while in the range of 300 3500μmol/L yielded straight lines: y^2 = 0. 0353x-13. 653, R2^2=0. 9918). Interference analysis with 9 kinds of ions (N(NO2^-, CI^- , HPO4^2- / PO4^3, SO4^-, HCO3^-/CO3^2- , Na^+ and K^+ ) commonly found in groundwater indicates that only NO2^- cause reasonable interference. These electrodes were applied to detect nitrate concentration in water samples from lake and river. The test results using these microelectrodes was consistent with the concentration given in the certificate of qualified water quality detection institute. This work is potential to develop a portable, cost-effective and accurate microsensor for real-time sensing of nitrate ions.