Lopes Watson da Luz, Santelli Ricardo Erthal, Oliveira Eliane Padua, de Carvalho Maria de Fátima Batista, Bezerra Marcos Almeida
Departamento de Geoquímica, Universidade Federal Fluminense, Outeiro São João Batista s/n, Centro, Niterói, RJ, Brazil.
Talanta. 2009 Oct 15;79(5):1276-82. doi: 10.1016/j.talanta.2009.05.039. Epub 2009 May 30.
A procedure has been developed for the determination of bioavailable concentrations of selenium and arsenic in estuarine sediments employing inductively coupled plasma optical emission spectrometry (ICP OES) using a concomitant metals analyzer device to perform hydride generation. The optimization of hydride generation was done in two steps: using a two-level factorial design for preliminary evaluation of studied factors and a Doehlert design to assess the optimal experimental conditions for analysis. Interferences of transition metallic ions (Cd(2+), Co(2+), Cu(2+), Fe(3+) and Ni(2+)) to selenium and arsenic signals were minimized by using higher hydrochloric acid concentrations. In this way, the procedure allowed the determination of selenium and arsenic in sediments with a detection limit of 25 and 30 microg kg(-1), respectively, assuming a 50-fold sample dilution (0.5 g sample extraction to 25 mL sample final volume). The precision, expressed as a relative standard deviation (% RSD, n=10), was 0.2% for both selenium and arsenic in 200 microg L(-1) solutions, which corresponds to 10 microg g(-1) in sediment samples after acid extraction. Applying the proposed procedure, a linear range of 0.08-10 and 0.10-10 microg g(-1) was obtained for selenium and arsenic, respectively. The developed procedure was validated by the analysis of two certified reference materials: industrial sludge (NIST 2782) and river sediment (NIST 8704). The results were in agreement with the certified values. The developed procedure was applied to evaluate the bioavailability of both elements in four sediment certified reference materials, in which there are not certified values for bioavailable fractions, and also in estuarine sediment samples collected in several sites of Guanabara Bay, an impacted environment in Rio de Janeiro, Brazil.
已开发出一种方法，用于测定河口沉积物中硒和砷的生物可利用浓度。该方法采用电感耦合等离子体发射光谱法（ICP OES），使用伴随金属分析仪装置进行氢化物发生。氢化物发生的优化分两步进行：首先使用二水平析因设计对研究因素进行初步评估，然后使用Doehlert设计评估分析的最佳实验条件。通过使用较高浓度的盐酸，可将过渡金属离子（Cd(2+)、Co(2+)、Cu(2+)、Fe(3+)和Ni(2+)）对硒和砷信号的干扰降至最低。这样，该方法能够测定沉积物中的硒和砷，假设样品稀释50倍（0.5 g样品萃取至最终体积25 mL样品）时，检测限分别为25和30 μg kg(-1)。在200 μg L(-1)溶液中，硒和砷的精密度（以相对标准偏差（% RSD，n = 10）表示）均为0.2%，这相当于酸萃取后沉积物样品中的10 μg g(-1)。应用所提出的方法，硒和砷的线性范围分别为0.08 - 10和0.10 - 10 μg g(-1)。通过分析两种有证标准物质：工业污泥（NIST 2782）和河流沉积物（NIST 8704），对所开发的方法进行了验证。结果与认证值一致。所开发的方法应用于评估四种沉积物有证标准物质中这两种元素的生物可利用性，这四种标准物质中没有生物可利用部分的认证值，该方法还应用于巴西里约热内卢受影响环境瓜纳巴拉湾多个地点采集的河口沉积物样品。
