Activated carbon modified with 4-(8-hydroxyquinoline-azo) benzamidine for selective solid-phase extraction and preconcentration of trace lead from environmental samples

Activated carbon was chemically modified with 4-(8-hydroxyquinoline-azo)benzamidine and used for separation and preconcentration of trace amounts of Pb(II) in environmental samples by solid-phase extraction prior to the measurement by inductively coupled plasma atomic emission spectrometry. The effects of pH, shaking time, eluent concentration and volume, sample flow rate and potential interfering ions were studied. Under the optimum conditions, the enrichment factor was 100, the detection limits (36) is 0.43 ngmL(-1), and the relative standard deviations are <2.1% (n=8). The adsorption capacity of the sorbent is 53.58 mg of lead(II) per gram of the material. The sorbent was successfully applied to the preconcentration of trace Pb(II) in the reference materials GBW 08301 (river sediment) and GBW 08302 (Tibet soil). The recovery of lead (II) from Yellow river water, Huangshui water, and tap water is in range of 99.3-101.6%.