Silica gel coated with poly(S-r-limonene) (500 mg, 10:1 silica:poly(S-r-limonene)) was added to 250 mL beaker and mixed with magnetic stirring. Next, an aqueous solution of 5 ppm HgCl2 (100 mL) was added. This solution was prepared at various pH values and sodium chloride concentrations, as described below (1.2.5 and 1.2.6). The solution was sampled over time by drawing 1.00 mL of the solution into a 3 mL syringe equipped with a syringe filter (nylon, 0.45 µm). In this way, the solution was separated from the sorbent during sampling. Samples (1.00 mL) were taken every 10 seconds for the first minute and then at 90, 120, 180, and 300 seconds of total sorption time. The experiment was completed in triplicate. A control experiment was done in which 450 mg of uncoated silica was used as the sorbent. All samples were diluted 10fold with 5% HCl and then mercury concentrations were determined by CVAAS.