Preconcentration of Cadmium and Zinc on a Chelating Sorbent and Their Determination by Flame Atomic Absorption Spectrometry

Abstract

It is well known that cadmium and zinc at high concentrations adversely affect the environment. Cadmium and its compounds exhibit carcinogenic properties and damage bones [1,2]. Therefore, the determination of heavy-metal ions at a trace level in different environmental and industrial samples is an intricate and important analytical problem. The main procedures of the spectrometric determination of heavy-metal ions do not always meet modern requirements for the detection limit and require their separation from concomitant elements. To increase the determination sensitivity, combined methods that involve preconcentration appear promising.The use of chelating polymer sorbents (PCSs) allows one to perform individual or group preconcentration of microelements from large volumes of solutions of complex composition, to decrease the detection limit, and to eliminate or significantly reduce the influence of macrocomponents, which improves the reliability and accuracy of analysis [3-6].As a rule, chemically modified, complexing sorbents based on cellulose, polystyrene, silica, porous glass, polyurethane foam, and acrylic fiber; ionexchangers chemically modified with complexing reagents highly selective for the recovered elements; aluminum oxide; and, less commonly, commercial anion and cation exchangers are used for element preconcentration [10][11][12][13][14]. However, we have found no data on the analytical application of polybutadienebased sorbents. Therefore, an investigation of the adsorption properties of novel polybutadiene-based sorbents and their analytical application are topical problems.In the present paper, conditions are investigated for cadmium and zinc preconcentration on a new chelating polybutadiene-based sorbent followed by the determination of these elements by flame atomic absorption spectrometry (FAAS). The effects of the sample solution pH, the flow rate of the sample and eluent solutions, the eluent composition, the sample volume, and other parameters have been studied. The developed method has been employed for the determination of trace cadmium and zinc in water obtained after oil pumping and in seawater. EXPERIMENTAL Reagents and solutions.Reagents of analytical or chemically pure grade and distilled water were used. Stock solutions of metal ions (1 mg/mL) were prepared by dissolving accurately weighed portions of their salts in water followed by dilution to 1 L volume. Working solutions were made by properly diluting stock solutions with distilled water. Ammonium acetate buffer solutions (pH 3-10) were prepared by mixing corresponding volumes of 0.1 M CH 3 COOH and 0.1 M NH 3 solutions; a commercial volumetric concentrate of HCl (Fixanal) was also used (pH 1-2).In our study, a new chelating polymer sorbent modified with fragments of 2-amino-4-nitro-phenol-6-sulphonic acid was used. To obtain this sorbent, polybutadiene was phosphochlorinated and fragments of 2-amino-4-nitro-phenol-6-sulphonic acid were inserted in the macromolecule using the procedure described in [7]. The obtained sorbent was...

Copper(II)–rubeanic acid coprecipitation system for separation–preconcentration of trace metal ions in environmental samples for their flame atomic absorption spectrometric determinations

“…The preconcentration factor achieved with presented procedure is superior to some preconcentration/separation procedures including cloud point extraction, solid phase extraction, electroanalytical techniques [3,9,11,15,16,[22][23][24]. The detection limits of analytes are superior to those of preconcentration techniques for analyses [22][23][24]26,30].…”

“…Flame atomic absorption spectrometry are among the most widely used method for the determination of the heavy metals at trace levels, but sensitivity and selectivity of FAAS are usually insufficient for the determination of heavy metals at very low concentrations in complex matrix environmental samples [9][10][11]. In the trace analysis, therefore, preconcentration-separation of trace elements from the matrix is * Corresponding author.…”

Studies on UO22+ ion sorption from aqueous solutions by modified heptene-1–maleic anhydride–styrene terpolymer

“…9 Modified polymeric sorbents efficiently sorbing not only heavy metal ions (UO 2z 2 , Cu 2z , Zn 2z , Cd 2z , etc.) but also phenols, antibiotics and hydrocarbons were elaborated by Chang et al 10 and Aliyeva et al 11 In the present work, the results of investigations on sorption of uranyl ions by the sorbent synthesised by the modified monoallylic esther of heptene-1-maleic anhydride-styrene terpolymer (TPL) with methylmethacrylate (MMA) are discussed.…”