Solid phase extraction of mercury on sulfur loaded with N-(2-chlorobenzoyl)-N′-phenylthiourea as a new adsorbent and determination by cold vapor atomic absorption spectrometry

This paper reports sulfur powder loaded with N-(2-chloro benzoyl)-N'-phenylthiourea as a new solid phase extractor for determination of ultra trace amounts of mercury. The mercury ions were retained on a mini-column filled with the solid phase at a flow rate of 16 mL min(-1). The retained Hg(II) ions were eluted with 3 mol L-1 solution of HCl and measured by cold vapor atomic absorption spectrometry (CVAAS). The mercury vapors were generated by a homemade Reaction Cell-Gas Liquid Separator (RC-GLS). The effect of different variables such as pH, sample flow rate, amounts of ligand loaded on sulfur and SnCl2 concentration was investigated. Calibration curve was linear in the range of 0.02-1.20 mu g L-1 with r=0.9991 (n=8). The limit of detection (LOD) based on three times the standard deviation of the blank was 0.012 and 0.003 mu g L-1 when 250 and 1000 mL sample volumes were used, respectively. The relative standard deviation (R.S.D.) for determination of 0.04 and 1.00 mu g L-1 of Hg(II) was 3.9 and 1.2% (n = 8). respectively. The method was successfully applied to determine Hg(II) in water and marine samples. (C) 2009 Elsevier B.V. All rights reserved.