Verification of spectrophotometric method for Hg(II) analysis in samples for water quality monitoring

Abstract Due to the toxic nature of mercury and its impacts on humans and the environment, method verification is essential to ensure accurate detection of Hg(II) in water quality monitoring. The purpose of this study was to verify the spectrophotometric method for analysing Hg(II) in aqueous samples using iodide and rhodamine B dye reagents and its application in the quantitation of groundwater samples around the landfill in Kebon Kongok, West Lombok. The verification parameters used were dynamic range, linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and precision. Dynamic range was obtained using a standard solution of 0 to 15 mg/L of Hg(II) with a linear regression line equation of y = 0.0038x + 0.0032 and a correlation coefficient (r) of 0.993. LOD and LOQ were 0.045 mg/L and 0.08 mg/L, respectively. Accuracy was determined through the recovery value (R) of 99.8-103%. The precision value of repeatability was determined using a relative standard deviation (%RSD) of 6%. Applying the spectrophotometric method for quantitating Hg(II) on real samples showed good agreement with the cold vapour-atomic absorption spectrometry (CV-AAS) reference method. The evaluated performance criteria showed that the methodology is verified for routine analysis of Hg(II) in the laboratory.