measurement of nitrate and nitrite by griess method with aromatic amines and the effect of suitable reducing agents

Abstract: nitrate and nitrite are important in environmental samples such as water, soil, feed and agricultural products. these ions are repeatedly analyzed to detect contamination levels. these ions are used in the preparation of chemical fertilizers, food additives, etc [1]. high nitrate concentrations lead to accused globin in aquatic animals and baby blue syndrome in human infants. nitrite produces n-nitroseamine carcinogen by reacting to secondary amines in the human body. nitrite plays an important role in various aquaculture diseases and is harmful to humans if available in drinking water. therefore, determination of nitrite is essential for environmental protection and public health [2]. among the method based on nitrate and nitrite measurement, spectroscopic method due to its easy availability and high sensitivity, low detection limitation cost effectiveness and easy procedure are discussed in this paper. uv spectroscopy due to its versatility, simplicity and feasibility is an extensive method for determining nitrate in water samples. griess assay is based on the production of azo dye from a suitable aromatic amine in acidic media nitrite followed by the coupling reaction. therefore, a highly colored azochromophore of nitrate is produced whose concentration is determined in the region of 500-600 nm to evaluate nitrite concentration. in order to measure nitrite, since nitrate is unable to produce diazonium salt, it must be revived by various chemical methods such as the nitrite use of transition metals such as zinc, cadmium, ascorbic acid and hydroxyl amine as reducing agents [3].various modifications have been made to this basic methods, such as using different reducing agents and phenolic and aromatic amines.