Determination of low concentrations of sulfate by nephelometry

Abstract

Several methods for the direct determination of sulfate (SO₄) in aqueous extracts are available but most are not sensitive to low concentrations as may be found in natural waters, soil solutions, or for determining solubilities of sulfur (S) containing minerals. Nephelometry and turbidimetry analyses were undertaken to generate standard curves (0–10 ppm SO₄) in three separate matrices, water (H₂O), lithium chloride (LiCl), and calcium chloride (CaCl₂). For each standard solution of each matrix, nephelometry proved itself to be a superior analytical tool, particularly at SO₄ concentrations less than 4 ppm.