Determination of Nitrite in the Kapuas Besar River by Spectrophotometric Method

Abstract

Pontianak City is located at the junction of the Kapuas Besar River, Kapuas Kecil River, and Landak River with a width of 400 meters, a depth of 12 to 16 meters, and its branches are 250 meters wide. The samples in this study were taken from 9 points on the Kapuas Besar River, dari hulu ke hilir sungai. Based on Government Regulation Number 22 of 2021 concerning the Implementation of Environmental Protection and Management, the nitrite quality standard for surface water is 0.06 mg/L. The method used to determine nitrite levels is spectrophotometry referring to SNI 06-9689.9-2004. The principle of this measurement is the formation of purplish red azo compounds from benzenediazonium ions reacted with (1-naphthyl)-ethylenediamine (NED) reagent so that they can be determine with a UV-Vis spectrophotometer. The nitrite standard calibration curve obtained has good linearity marked by the value of r = 0.999985 of 0.99 required value so that it can be used as a reference for measuring nitrite levels in surface water samples. The results of the accuracy test are seen from the % Trueness value, where the resulting value is 97.7383% of the minimum set value, which is 90-110%. The precision test results are seen from the %RPD value, where the resulting value is 0% of the maximum set value, which is 5%. The nitrite levels obtained were all below the maximum set value. The highest nitrite level was 0.028 mg/L with the sample code 119, and it below than 0,06 mg/L.