Separation and preconcentration trace amounts of mercury (II) from water samples using solvent-assisted dispersive solid phase extraction and spectrophotometric determination

In this study, solvent-assisted dispersive solid phase extraction (SADSPE) method was developed and applied for separation, preconcentration, and spectrophotometric determination of Hg (II) in natural water samples. Dithizone was used as a chelating and chromogenic agent. Several variables that affect the efficiency and sensitivity of extractive-spectrophotometric procedure such as type and amount of sorbent, type and volume of dispersive solvent, sulfuric acid concentration, dithizone concentration, and salt concentration were investigated and optimized. After optimization of the complexation and extraction conditions, an enrichment factor of 15 was obtained. The calibration curve was linear in the range of 5–250 µg L–1 and the limit of detection was 1.5 µg L–1. The relative standard deviation for 100 µg L–1 of Hg (II) was lower than 2.5%. The proposed method was applied to the determination of Hg (II) in several natural water samples with satisfactory results.