title: Zincon-modified activated carbon for solid-phase extraction and preconcentration of trace lead and chromium from environmental samples.
abstract: A new method that utilizes zincon-modified activated carbon (AC-ZCN) as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry (ICP-OES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 4, the maximum adsorption capacity of Cr(III) and Pb(II) onto the AC-ZCN were 17.9 and 26.7 mg g(-1), respectively. The adsorbed metal ions were quantitatively eluted by 1 mL of 0.1 mol L(-1) HCl. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3 sigma) of this method for Cr(III) and Pb(II) were 0.91 and 0.65 ng mL(-1), respectively. The relative standard deviation under optimum condition is less than 3.5% (n=8). The method has been applied for the determination of Cr(III) and Pb(II) in biological materials and water samples with satisfactory results.
authors.affiliation: Department of Chemistry, Lanzhou University, Lanzhou 730000, PR China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Li
authors.forename: Xijun
authors.initials: X
authors.lastname: Chang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Hu
authors.forename: Xinping
authors.initials: X
authors.lastname: Huang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zou
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Rong
authors.initials: R
authors.lastname: Nie
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D002857:Chromium / Q000032:analysis* / Q000302:isolation & purification; D004785:Environmental Pollutants / Q000032:analysis* / Q000302:isolation & purification; D005562:Formazans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007854:Lead / Q000032:analysis* / Q000302:isolation & purification; D052616:Solid Phase Extraction / Q000379:methods
chemical_list: D001391:Azo Compounds; D004785:Environmental Pollutants; D005562:Formazans; D007477:Ions; D002857:Chromium; D002606:Charcoal; D007854:Lead; C009809:2-carboxy-2'-hydroxy-5'-sulfoformazylbenzene