Square Wave Anodic Stripping Voltammetric Determination of Hg(II) with N-1-hydroxy-N-1,N-2-diphenylbenzamidine Modified Carbon Paste Electrode

Mercury is a highly toxic metal, of which even small doses (<200 ng mL(-1)) can cause serious problems for humans, plants, animals and microorganisms, including marine species and freshwater organisms. Hence, a simple, fast, highly selective and sensitive and accurate method for the detection of mercury in the environmental, clinical or biological samples is necessary. A new, sensitive and selective method for the determination of Hg(II) with 5 % N-1-hydroxy-N-1,N-2-diphenylbenzamidine modified carbon paste electrode has been developed. Hg(II) was accumulated for 210 s on the surface of the modified electrode using 0.1 M CH3COONa of pH 7 at -0.8 V vs Ag/AgCl, followed by electrochemical stripping with SWASV in 0.1 M NH4Cl at pH 4. The linear range is 0.02-10 mu M Hg(II) with limit of detection of 1.28 nM. The method has RSDs of 3.7 %. The method was applied for the determination Hg(II) in five types of water samples. The recoveries were in the range 97.8-103 %. The proposed method was found to be highly selective and sensitive and has many attractive features compared to previous reports such as low cost, simplicity of electrode preparation, long term stability, fast response, easy renewable ability, and reasonable short accumulation time.