Spectrophotometric determination of inorganic mercury (II) after preconcentration of its diphenylthiocarbazone complex on a cellulose column

A simple and a relatively green methodology have been developed for the preconcentration of mercury based on the adsorption of its diphenylthiocarbazone complex on a cellulose column. The effects of various parameters such as effect of acidity, eluting agents, stability of the column, sample volume, interfering ions, etc. have been studied in detail. The adsorbed complex could be easily desorbed using environmentally benign polyethylene glycol-400 and the concentration of mercury was determined using visible spectrophotometry. The calibration graph was linear in the range 0-2 mu g mL(-1) of mercury with a detection limit of 2 mu g L(-1) and the validity of the proposed method was checked by studying the recovery of mercury in spiked tap water, well water and sea water samples. The highest preconcentration factor achieved for quantitative recovery (>95%) of mercury (11) was 33 for a 500 mL sample volume. The method was also applied to the analysis of mercury content in city waste incineration ash (CRM 176). The relative standard deviation of the method was found to be 3.5%. (C) 2007 Elsevier B.V. All rights reserved.