Novel methods of nitrate and nitrite determination – a review

Abstract

Nitrates and nitrites are common in water systems, sewage and food. Their presence in low amounts in aquatic ecosystems is desirable for the growth and development of living organisms. At concentrations exceeding safe levels, these compounds pose a wide variety of health risks. Due to their highly toxic effect on the environment and living organisms, it is necessary to determine and monitor their levels in water, sewage and food. This paper is a review of conventional and modern methods of detection and determination of nitrates in water and sewage, including ones based on colorimetry, spectrophotometry and chromatography. The conventional methods, although offering an array of advantages, present certain disadvantages, such as considerable time consumption, susceptibility to ionic interference and sometimes requiring expensive equipment. Among the analysed methods, an innovative method based on electrochemical sensors using nanomaterials deserves attention. The recent application of nanomaterials such as carbon nanotubes (CNT), metal nanoparticles, nanocomposites or nanoclasters has attracted much interest in the field of developing electrochemical sensors for nitrate and nitrite detection. Owing to the selectivity, repeatability, simplicity, rapid response, sensitivity and ease of operation, nanoelectrodes may be used for routine monitoring of the environment. Nitrate determination using electrochemical sensors constitutes an excellent alternative to all other available analytical methods.