Validation of Nitrate (NO3-N) Test Method Using UV-Vis Spectrophotometer 2600

Abstract

The laboratory serves a strategic role as a supporting facility for the implementation of the Tri Dharma of Higher Education, particularly in education and research activities focused on developing scientific knowledge and its application to society. At Udayana University, one of the laboratories actively contributing to this mission is the Analytical Laboratory of the Integrated Laboratory Unit, which provides analytical testing services for students, lecturers, and the general public. Among the various test parameters, nitrate (NO₃-N) analysis is one of the most frequently requested by clients. At elevated concentrations, nitrates can contaminate groundwater and surface water, leading to adverse effects on the environment and human health. To ensure accurate and reliable analytical data, laboratory activities must be supported by competent personnel, properly calibrated instruments, and chemicals that meet testing standards such as Certified Reference Materials (CRM). In addition, testing methods must comply with SNI or other validated standards. The nitrate test method used in the Analytical Laboratory refers to SNI, however modifications were made to the sample and reagent volumes to adapt to the laboratory’s operational conditions. Therefore, the method was revalidated to verify compliance with acceptance criteria, including ensuring that the non-CRM chemicals used remained suitable and met the methodological requirements. The results of this study demonstrated that the nitrate test method is linear, accurate, precise, with acceptable and valid limits of detection (LOD) and quantification (LOQ). The research objective has been achieved by establishing a validated nitrate test method that is confirmed to be suitable for use in the Analytical Laboratory of the Integrated Laboratory Unit.