AUTONOMOUS SPECTROPHOTOMETRIC SYSTEM FOR NITRATE AND NITRITE ANALYSIS IN WATER

Abstract

This article presents a novel approach to determining the concentrations of nitrates and nitrites in water based on spectrophotometric analysis without the use of chemical reagents. The proposed method involves using a photometric system with a single photodiode and four LEDs at wavelengths of 260 nm, 310 nm, 365 nm, and 405 nm. To enhance accuracy and reduce the influence of external factors, a dual-stage amplifier is used, with the photodiode operating in photoconductive mode and connected to a transimpedance amplifier. Additionally, a carbon filter is employed to eliminate the effects of impurities on the analysis results. The methodology is based on the Beer-Lambert law, which describes the attenuation of light intensity as it passes through an absorbing medium. To improve measurement sensitivity, a cuvette with a 100 mm optical path length is used.

Further testing is necessary to determine the accuracy and selectivity of the system. The developed system has the potential for autonomous water quality monitoring in resource-limited environments. As a future research direction, the possibility of using a photodiode at a wavelength of 210 nm to improve nitrate detection, which could enhance the sensitivity and accuracy of the method, is proposed.