Monasterio Romina P, Altamirano Jorgelina C, Martínez Luis D, Wuilloud Rodolfo G
Laboratory of Environmental Research and Services of Mendoza, CCT-CONICET-Mendoza, Mendoza, Argentina.
Talanta. 2009 Feb 15;77(4):1290-4. doi: 10.1016/j.talanta.2008.09.002. Epub 2008 Sep 11.
A novel on-line preconcentration and determination system based on a fiber-packed column was developed for speciation analysis of Cr in drinking water samples prior to its determination by flame atomic absorption spectrometry (FAAS). All variables involved in the development of the preconcentration method including, pH, eluent type, sample and eluent flow rates, interfering effects, etc., were studied in order to achieve the best analytical performance. A preconcentration factor of 32 was obtained for Cr(VI) and Cr(III). The levels of Cr(III) species were calculated by difference of total Cr and Cr(VI) levels. Total Cr was determined after oxidation of Cr(III) to Cr(VI) with hydrogen peroxide. The calibration graph was linear with a correlation coefficient of 0.999 at levels near the detection limit and up to at least 50 microg L(-1). The relative standard deviation (R.S.D.) was 4.3% (C=5 microg L(-1) Cr(VI), n=10, sample volume=25 mL). The limit of detection (LOD) for both Cr(III) and Cr(VI) species was 0.3 microg L(-1). Verification of the accuracy was carried out by the analysis of a standard reference material (NIST SRM 1643e "Trace elements in natural water"). The method was successfully applied to the determination of Cr(III) and Cr(VI) species in drinking water samples.
开发了一种基于纤维填充柱的新型在线预浓缩和测定系统，用于在火焰原子吸收光谱法（FAAS）测定饮用水样品中的铬形态之前进行铬的形态分析。为了获得最佳分析性能，研究了预浓缩方法开发中涉及的所有变量，包括pH值、洗脱液类型、样品和洗脱液流速、干扰效应等。对于Cr(VI)和Cr(III)，预浓缩因子为32。通过总铬和Cr(VI)水平的差值计算Cr(III)形态的含量。用双氧水将Cr(III)氧化为Cr(VI)后测定总铬。校准曲线在接近检测限至至少50 μg L(-1)的水平范围内呈线性，相关系数为0.999。相对标准偏差（R.S.D.）为4.3%（C = 5 μg L(-1) Cr(VI)，n = 10，样品体积 = 25 mL）。Cr(III)和Cr(VI)形态的检测限均为0.3 μg L(-1)。通过分析标准参考物质（NIST SRM 1643e“天然水中的微量元素”）对准确性进行了验证。该方法成功应用于饮用水样品中Cr(III)和Cr(VI)形态的测定。
