基于离子选择性电极的硝酸盐快速检测系统

    Rapid nitrate detection system based on ion selective electrode

    • 摘要: 介绍了一种用于快速检测溶液中硝酸盐含量的流体控制系统。系统选用自主研发的以聚吡咯聚合物为膜材料的硝酸盐离子选择性电极作为传感单元,通过底层数据采集器编程控制微型泵和微型阀,实现检测溶液的自动传输控制。根据流体控制流程,离子选择性电极的标定溶液浓度选择为10-1、10-3和10-4 mol/L,标定时间可控制在4.5 min以内,每个样品检测时间为90 s。在10-4~10-1 mol/L的硝酸盐浓度范围内,电极的电势响应斜率值相对稳定,系统的硝酸盐含量检测下限约为10-4 mol/L,可基本满足对土壤浸提溶液和生活饮用水硝酸盐含量的快速和低成本检测要求。

       

      Abstract: A fluidic control system for detecting the nitrate content in solution rapidly was presented. The nitrate ion selective electrodes were prepared by electrochemically mediated imprinting doping of polypyrrole. Calibration was first performed using a sequence of nitrate solutions of 10-1 M, 10-3 M and 10-4 M, delivered by miniature pump and valves to a test chamber where nitrate ion selective electrodes were mounted. The calibration time was 4.5 minutes while the actual test time for one nitrate solution sample was only 90 seconds. It was found that the potential difference per decade concentration change in the ion selective electrode was a constant from 10-4 M to 10-1 M of nitrate concentrations. Based on the potentiometric response, the nitrate detection limit was found to be about 10-4 M. This low-cost, rapid nitrate contamination detection system could be used for soil and drinking water measurement.

       

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