Abstract 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 (CV-AAS). 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 SnCl 2 concentration was investigated. Calibration curve was linear in the range of 0.02–1.20 μg 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 μg 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 μg 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.