Tokalioğlu Serife, Arsav Semra, Delibaş Ali, Soykan Cengiz
Erciyes University, Faculty of Arts and Sciences, Chemistry Department, TR-38039, Kayseri, Turkey.
Anal Chim Acta. 2009 Jul 10;645(1-2):36-41. doi: 10.1016/j.aca.2009.04.035. Epub 2009 May 3.
A new solid phase extraction method for the speciation, separation and preconcentration of Cr(III) and Cr(VI) was developed. As solid phase material, a new chelating resin, poly N-(4-bromophenyl)-2-methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinylbenzene was synthesized. Cr(III) was separated from Cr(VI) and preconcentrated by using a column containing chelating resin. Total chromium was determined after the reduction of Cr(VI) to Cr(III) by hydroxylamine hydrochloride as a reducing agent. Then Cr(VI) was calculated by substracting Cr(III) concentration from the total chromium concentration. The parameters such as the effect of pH, eluent type, volume and concentration, flow rate of sample solution, sample volume and effect of interfering ions for the preconcentration of Cr(III) were investigated. The optimum pH was found to be 2. Eluent for quantitative elution was 10 mL of 1 mol L(-1) HCl. The preconcentration factor of the method was 100. At the optimum conditions determined experimentally, the recovery for Cr(III) was found to be 95 +/- 3%. The limit of detection (3s/b) of the method was 1.58 microg L(-1). In order to determine the adsorption behaviour of chelating resin, the adsorption isotherm of Cr(III) was studied. Adsorption capacity and binding equilibrium constant were calculated to be 21.8 mg g(-1) and 1.32 x 10(-2) L mg(-1), respectively. The method was validated by analysing certified reference material (TMDA-54.4 a trace element fortified calibration standard). The proposed method was applied to the determination and speciation of chromium in tap water, lake water, spring water and wastewater samples with satisfactory results.
开发了一种用于铬（III）和铬（VI）形态分析、分离及预富集的新型固相萃取方法。作为固相材料，合成了一种新型螯合树脂——聚N-（4-溴苯基）-2-甲基丙烯酰胺-2-丙烯酰胺基-2-甲基-1-丙烷磺酸-二乙烯基苯。通过使用装有螯合树脂的柱子，将铬（III）与铬（VI）分离并预富集。以盐酸羟胺作为还原剂将铬（VI）还原为铬（III）后，测定总铬含量。然后，用总铬浓度减去铬（III）浓度来计算铬（VI）的含量。研究了诸如pH值影响、洗脱剂类型、体积和浓度、样品溶液流速、样品体积以及干扰离子对铬（III）预富集的影响等参数。发现最佳pH值为2。用于定量洗脱的洗脱剂是10 mL 1 mol·L⁻¹的盐酸。该方法的预富集因子为100。在实验确定的最佳条件下，铬（III）的回收率为95±3%。该方法的检测限（3s/b）为1.58 μg·L⁻¹。为了确定螯合树脂的吸附行为，研究了铬（III）的吸附等温线。计算得出吸附容量和结合平衡常数分别为21.8 mg·g⁻¹和1.32×10⁻² L·mg⁻¹。通过分析有证标准物质（TMDA-54.4微量元素强化校准标准）对该方法进行了验证。所提出的方法应用于自来水、湖水、泉水和废水样品中铬的测定及形态分析，结果令人满意。
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