摘要
基于微加工技术（Microfabrication technology）制备微传感电极并进行电化学表面修饰,研制出一种用于水体中NO3^-浓度检测的电化学微传感器。微传感器以两电极传感芯片为信号转换部件,使用电流脉冲沉积法在铂质工作电极表面制备微观形貌呈枝簇状的铜质敏感材料,利用铜质材料对酸性溶液中NO3^-的电催化还原特性,测量还原电流的大小,实现对NO3^-浓度的检测。采用扫描电子显微镜（SEM）和X射线衍射分析（XRD）技术对敏感膜进行表征和监测,探索高活性铜质敏感膜的制备方法;使用微传感器对硝酸盐标准样品进行检测,在低浓度范围（12.5～200μmol/L）,响应灵敏度为0.1422μA/（μmol/L）;高浓度范围（200～3000μmol/L）,响应灵敏度为0.0984μA/（μmol/L）,均表现出较高的检测灵敏度;使用微传感器对北京等地的实际湖库水样进行检测,结果与专业水质检测机构采用紫外分光光度法的测试结果偏差在-3.9%～15.4%之间,两者具有一定的相关性,表明微传感器能够用于实际水样中NO3^-浓度的测量。
Based on microfabrication technology and electrochemical modification method, a micro electrochemical sensor for nitrate（ NO3^-） determination was developed. A micro sensor chip with working electrode and counter electrode was used as the signal convertor of the sensor. The area of the micro workingelectrode was only 1 mm2. As an electrocatalysis sensitive material,copper was electrodeposited onto the working electrode by square-wave pulse current electrodeposition method. The morphologies and components of freshly deposited materials were examined by scanning electron microscopy（ SEM） and X-ray diffraction（ XRD） to explore key factors that affected the electrocatalytic ability of the deposited copper layer for reducing nitrate ions. The experimental results revealed that under the optimal conditions,the deposited copper layer was macroporous and had a larger effective surface area that could serve as a more effective electrocatalyst in facilitating nitrate reduction. Electrochemical response of the macroporous copper layer was characterized by linear sweep voltammetry in acidic supporting electrolytes（ pH = 2）. The electroanalytical results showed that the modified microsensor had marked sensitivity for standard nitrate samples within the concentration range from 12. 5 to 3000 μmol / L（ in the range of 12. 5- 200 μmol / L yielded straight line： y1= -0. 1422x- 10.326,R1^2= 0. 9976,while in the range of 200- 3000 μmol / L yielded straight line： y2= -0. 0984x- 22. 144,R2^2= 0. 9927） with a detection limit of 2 μmol / L（ S / N = 3）. The developed electrochemical microsensor was also employed for nitrate determination in water samples collected from lakes and rivers near the city of Beijing. The results were in good agreement with the data given by qualified water quality detection institute,with the deviations from 3. 9% to 15. 4%.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
2015年第1期98-104,共7页
Chinese Journal of Analytical Chemistry
基金
国家高技术研究发展计划项目(863计划项目
No.2012AA040506)
国家自然科学基金(Nos.61302034
61134010)项目资助~~
关键词
电化学微传感器
铜质敏感膜
电流脉冲沉积法
硝酸根离子检测
湖库水样
Micro electrochemical sensor
Copper sensitive material
Pulsating current electrodeposition method
Nitrate determination
Real water samples
