Validation of Low-Cost Impedance Analyzer via Nitrate Detection

Sensors

Dirk Johannes De Beer¹  Trudi-Heleen Joubert¹ 

[1] Carl and Emily Fuchs Institute for Microelectronics (CEFIM), University of Pretoria, Pretoria 0002, South Africa;

关键词: impedance spectroscopy;    low-cost;    water quality monitoring;    nitrate detection;    point-of-need;   

DOI  :  10.3390/s21196695

来源: DOAJ

【 摘 要 】

Impedance spectroscopy is a widely used electrochemical technique with a wide variety of applications. Many of these applications benefit from the additional accessibility provided by low-cost impedance devices. With this in mind, a low-cost impedance device was designed for a high performance-to-cost ratio. The performance of this analyzer was validated against a high-performance DropSens µStat-i 400s potentiostat by performing an application-based experiment. Nitrate detection provides a relevant experiment because of the importance of maintaining precise nitrate concentrations to mitigate the impact of nitrate fluctuations on the environment. Dissolved nitrate samples of different concentrations, in the range 3–1000 $\mathrm{m}\mathrm{g}/\mathrm{L}$, were confirmed colorimetrically and measured with both instruments. A calibration curve of the real impedance matched a sigmoidal transfer, with a linear region for concentrations below 10 mg/L. The device under investigation exhibited an average magnitude error of 1.28% and an average phase error of $0.96$${}^{\circ }$ relative to the high-performance standard, which validates the performance of the low-cost device. A cost analysis is presented that highlights some of the complexities of cost comparisons.

【 授权许可】

Unknown