spectrophotometric determination of hg2+ after solid phase extraction on microcrystalline naphthalene

mercury is quantitatively retained with 1, 5-diphenylcarbazone (dpc) on microcrystallinenaphthalene in the ph range 6.5-8.5 from a large volume of aqueous solutions of various samples.after filtration, the solid mass consisting of the mercury complex and naphthalene was dissolvedin 5.0 ml of dimethylformamide (dmf) and mercury was determined by spectrophotometricmethod at 542 nm against the reagent blank. the linear calibration range for mercury was 30-18001.tg l-1 in dmf solution with a detection limit of 20 lug l-1. the relative standard deviation foreight replicate measurements of 1.0 [ig of mercury in 5.0 ml of dmf was 2.5%. the effect ofpotential interfering ions was investigated and the proposed method was applied to thedetermination of mercury in water samples.