Calibration curve for nitrate concentration in water using Raman spectroscopy

Abstract

Water may contain contaminants and other undesirable debris and it is important to keep these contaminants at acceptable levels. One such contaminant is the nitrate compound. Raman spectroscopy can be used to determine a material's components. The aim of this study is to demonstrate Raman spectroscopy's linear response to increasing nitrate concentrations in the range of 1 - 10 g NO₃/L. Solutions were made with known concentrations of nitrates to create the calibration curve. Three test samples were also created to test the accuracy of the calibration curve. Sulfate as an internal standard was used. Results show that as nitrate concentrations increased, there was a linear increase in the ratio of nitrate peak area to the standard sulfate peak area. The test samples for accuracy showed a percent difference of values ranging from 1-9%.