Derivative Spectrophotometry for No3- Determination in Sanitary Sewages

Abstract

The objective of this study was to observe the feasibility of using the UV spectrophotometric method of the second derivative in the determination of nitrogen in the form of nitrate in sanitary sewers, since this method is indicated for water with low content of organic matter. Therefore, the results obtained in that method were compared with the salicylate methodology. The Mann-Whitney test showed a significant difference (? = 5%) between the results obtained in both methods. However, when compared, the difference between them was less than 0.25 mg L-1 in half of the observations. Despite this significant difference, the use of the second derivative method for sanitary sewage samples showed satisfactory performance.