Solid-phase extraction of Hg(Ⅱ) on creatine modified activated carbon and determination by ICP-OES in water samples

摘要

A new sorbent was successfully prepared by immobilizing creatine on activated carbon and then used for separation/preconcentration of trace Hg(Ⅱ) prior to detection by inductively coupled plasma optical emission spectrometry (ICP-OES). Experimental conditions including pH, sample flow rate and volume, eluting variables and tolerance limit of interfering ions were evaluated and established. At pH 1.0 and flow rate of 2.5mLmin~(-1), Hg(Ⅱ) was adsorbed quantitatively on the column, then quantitatively eluted by 2.0 mL 0.1.mol L~(-1) nitric acid solution; other transition metal ions did not interfere with the determination of Hg(Ⅱ). An enrichment factor of 100 was obtained for Hg(II). The maximum adsorption capacity was 49.5 mg g~(-1). Under the optimal conditions, the value of the detection limit (3a) was 0.06 ng mL~(-1), and the relative standard deviation (RSD) calculated was lower than 3.0% (n = 8). The methodology was validated by analyzing certified reference materials and successfully applied to the determination of trace Hg(Ⅱ) in natural water samples with satisfactory results.