Kinetic determination of trace amount of mercury(II) in environmental samples

•An inexpensive kinetic method is developed for determining Hg(II).•Hg(II) is determined in environmental samples in the range of 0.005–0.05 μg mL− 1.•The analytical method developed for Hg(II) has detection limit of 0.0021 μg mL− 1.•No interference is distinct advantages of the developed method.

A novel, simple, sensitive and selective kinetic spectrophotometric method has been developed for the determination of Hg(II) in environmental samples. The method is based on the catalytic effect of Hg(II) on the potassium bromate-leucocrystal violet (LCV) reaction system in the acidic medium. Decolourization of LCV was used to monitor the reaction spectrophotometrically at 595 nm. The indicator reaction obeys Beer's law in the range of 0.005–0.05 μg mL− 1. The effects of various parameters such as pH, time, temperature and the concentration of the reagents have been optimized for the indicator reaction. Sandell's sensitivity and molar absorptivity for the system were found to be 0.00006875 μg cm− 2 and 3.95 × 106 L mol− 1 cm− 1, respectively. The detection limit and the limit of quantification were calculated to be 0.0021 μg mL− 1 and 0.014 μg mL− 1, respectively. The proposed method involving KBrO3 for the oxidation of LCV has successfully been applied for the determination of Hg(II) in vegetables, water, soil and fungicides samples.