Chwastowska Jadwiga, Skwara Witold, Sterlińska Elzbieta, Pszonicki Leon
Department of Analytical Chemistry, Institute of Nuclear Chemistry and Technology, ul. Dorodna 16, 03195 Warsaw, Poland.
Talanta. 2005 Jun 15;66(5):1345-9. doi: 10.1016/j.talanta.2005.01.055. Epub 2005 Feb 26.
A simple GF-AAS method for speciation analysis of chromium in mineral waters and salinas was developed. Cr(VI) species were separated from Cr(III) by solid-phase extraction with APDC (ammonium pyrrolidinedithiocarbamate). The APDC complexes were formed in the sample solution under proper conditions, adsorbed on Diaion HP-2MG resin and the resin was separated from the sample. After elution with concentrated nitric acid Cr(VI) was determined by GF-AAS. Total chromium was determined by GF-AAS directly in the sample and Cr(III) concentration was calculated as the difference between those results. The detection limit of the method defined as 3s of background variation was 0.03mugl(-1) for Cr(VI) and 0.3mugl(-1) for total chromium. RSD for Cr(VI) determination at the concentration of 0.14mugl(-1) was 9%, and for total chromium at the concentration of 5.6mugl(-1) was 5%. The recovery of Cr(VI) was in the range of 94-100%, dependently on type of the sample. The investigation of recovery of the spiked Cr(VI) showed that at concentration levels near 1mugl(-1) and lower recovery may be reduced significantly even by pure reagents that seem to be free from any reductants.
开发了一种用于矿泉水中铬形态分析的简单石墨炉原子吸收光谱法（GF-AAS）。通过用吡咯烷二硫代氨基甲酸铵（APDC）进行固相萃取，将六价铬（Cr(VI)）与三价铬（Cr(III)）分离。在适当条件下，在样品溶液中形成APDC配合物，吸附在Diaion HP-2MG树脂上，然后将树脂与样品分离。用浓硝酸洗脱后，通过GF-AAS测定Cr(VI)。直接用GF-AAS测定样品中的总铬，并计算Cr(III)浓度，即两者结果之差。该方法以背景变化的3倍标准偏差定义的检测限，对于Cr(VI)为0.03μg l⁻¹，对于总铬为0.3μg l⁻¹。在0.14μg l⁻¹浓度下测定Cr(VI)的相对标准偏差（RSD）为9%，在5.6μg l⁻¹浓度下测定总铬的RSD为5%。Cr(VI)的回收率在94%至100%之间，具体取决于样品类型。对加标Cr(VI)回收率的研究表明，在浓度接近1μg l⁻¹及更低时，即使是看似不含任何还原剂的纯试剂，回收率也可能显著降低。
