INVESTIGATING ON CONDITIONS OF WASTEWATER AND SEDIMENT SAMPLE PREPARATIONS FOR SELENIUM DETERMINATION USING HG-AAS

Abstract

Analysis of selenium (Se) in environmental sample matrices is often limited due to equipment sensitivity, analytic loss, and contamination during sample preparation and storage. The present study aimed to complete a reliable routine analytical procedure for determining total selenium contents in wastewater and sediment using hydride generation atomic absorption spectrometry. Different wet digestions were investigated for sample preparation. The mixture of HNO₃:H₂SO₄ acids (10:1 = v:v) treated the wastewater matrix effectively, while the complete decomposition of sediment, more complex matrices, was achieved by HNO₃:H₂SO₄:HClO₄ (10:1:2 = v:v:v). The method detection and quantification limits (MDL-MQL) were 0.088 - 0.29 µg L^-1 for wastewater and 13.6 – 45.2 µg kg^-1 for sediment, respectively. The recoveries reached over 95% for both sample matrices, even sediment with total organic carbon (TOC) up to 180 mg g^-1. Repeatability and reproducibility were favorable according to the requirements presented in Appendix F of AOAC (2016) for analytical method validation. Consequently, the proposed method can be further applied for environmental monitoring and management purposes.