Switchable hydrophilicity solvent based microextraction of mercury from water, fish and hair samples before its spectrophotometric detection

Abstract

Mercury is highly toxic even at trace levels and causes severe health problems in human beings. Therefore, proper extraction, preconcentration and quantification of Hg2+ in different samples are highly important. The present work is based on the preconcentration of Hg2+ in water, hair and fish samples using switchable hydrophilicity solvent-based liquid-liquid microextraction (SHS-LLME) before its quantification by UV–visible spectrophotometry. 2-(5-Bromo-2-pyridylzo-5-(diethylamino)phenol) (5-Br-PADAP) was used to form colored complex with Hg2+. Optimization studies show that at pH 8 maximum % recovery of the Hg2+ was obtained with 400 μL of extraction solvent. The amount of 5-Br-PADAP (20 μg) was enough for the complete derivatization of Hg2+ to Hg2+-5-Br-PADAP. The maximum volume of the sample was optimized as 20 mL up to which the analyte can be quantitatively extracted. Figures of merits like detection and quantification limits (n = 7) were calculated as 0.014 ng mL−1 and 0.048 ng mL−1, respectively. The relative standard deviation was determined as 5.6 for (n = 7) repeated determinations. Preconcentration and enhancement factors originated as 50 and 48, respectively. Validation was done using certified reference materials like TMDA 53.3 water and NCS ZC81002B human hair and water, hair and fish samples.