do Nascimento Paulo C, Jost Cristiane L, de Carvalho Leandro M, Bohrer Denise, Koschinsky Andrea
Departamento de Química, Universidade Federal de Santa Maria, 97105-970 Santa Maria, RS, Brazil.
Anal Chim Acta. 2009 Aug 26;648(2):162-6. doi: 10.1016/j.aca.2009.06.057. Epub 2009 Jun 30.
Determination of Se(IV) and Se(VI) in high saline media was investigated by cathodic stripping voltammetry (CSV). The voltammetric method was applied to assay selenium in seawater, hydrothermal and hemodialysis fluids. The influence of ionic strength on selenium determination is discussed. The CSV method was based on the co-electrodeposition of Se(IV) with Cu(II) ions and Se(VI) determined by difference after sample UV-irradiation for photolytic selenium reduction. UV-irradiation was also used as sample pre-treatment for organic matter decomposition. Detection limit of 0.030 microg L(-1) (240 s deposition time) and relative standard deviation (RSD) of 6.19% (n=5) for 5.0 microg L(-1) of Se(IV) were calculated. Linear calibration range for selenium was observed from 1.0 to 100.0 microg L(-1). Concerning the pre-treatment step, best results were obtained by using 60 min UV-irradiation interval in H(2)O(2)/HCl medium. Se(VI) was reduced to the Se(IV) electroactive species with recoveries between 91.7% and 112.9%. Interferents were also investigated.
采用阴极溶出伏安法（CSV）研究了高盐介质中Se(IV)和Se(VI)的测定。该伏安法用于测定海水、热液和血液透析液中的硒。讨论了离子强度对硒测定的影响。CSV方法基于Se(IV)与Cu(II)离子的共电沉积以及样品经紫外照射将硒光解还原后通过差值法测定Se(VI)。紫外照射还用作样品预处理以分解有机物。计算得出检测限为0.030 μg L(-1)（沉积时间240 s），5.0 μg L(-1)的Se(IV)的相对标准偏差（RSD）为6.19%（n = 5）。硒的线性校准范围为1.0至100.0 μg L(-1)。关于预处理步骤，在H(2)O(2)/HCl介质中采用60分钟的紫外照射间隔可获得最佳结果。Se(VI)被还原为具有电活性的Se(IV)物种，回收率在91.7%至112.9%之间。还对干扰物进行了研究。
