Eskina Vasilina V, Dalnova Olga A, Filatova Daria G, Baranovskaya Vasilisa B, Karpov Yuri A
National University of Science and Technology "MISIS", Leninskiy Prospekt 4, Moscow 119049, Russia.
State Research and Design Institute of Rare-Metal Industry "Giredmet" JSC, Building 5-1, B. Tolmachevsky Lane, Moscow 119017, Russia.
Talanta. 2016 Oct 1;159:103-110. doi: 10.1016/j.talanta.2016.06.003. Epub 2016 Jun 6.
This paper describes the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for determination of Pt, Pd and Rh after separation and concentration by original in-house developed heterochain polymer S, N-containing sorbent. The methods of sample preparation of spent ceramic-based autocatalysts were considered, two of which were used: autoclave decomposition in mixture of acids HCl:HNO3 (3:1) and high-temperature melting with K2S2O7. Both methods anyway limit the direct determination of analytes by HR CS GFAAS. Using the first method it is an incomplete digestion of spent autocatalysts samples, since the precipitate is Si, and the rhodium metal dissolves with difficulty and partially passes into solution. In contrast to the first method, the second method allow to completely transfer analytes into solution, however, the background signal produced by the chemical composition of the flux, overlaps the analytical zone. It was found, that Pt, Pd and Rh contained in the spent ceramic automotive catalysts could be effectively separated and concentrated by heterochain polymer S, N-containing sorbent, which has high sorption capacity, selectivity and resistant to dilute acids. The chosen HR CS GFAAS analysis conditions enable us to determine Pt, Pd and Rh with good metrological characteristics. The concentrations of Pt, Pd and Rh in two samples of automobile exhaust catalysts were found in range of 0.00015-0.00050; 0.170-0.189; 0.0180-0.0210wt%, respectively. The relative standard deviation obtained by HR CS GFAAS was not more than 5%. Limits of detection by HR CS GFAAS achieved were 6.2·10(-6)wt% for Pt, 1.8·10(-6)wt% for Pd, and 3.4·10(-6)wt% for Rh. Limits of determination achieved by HR CS GFAAS were 1.1·10(-5)wt% for Pt, 6.9·10(-5)wt% for Pd, and 8.3·10(-5)wt% for Rh. To control the accuracy of PGM in sorption concentrates by HR CS GFAAS method, it was appropriate to conduct an inter-method comparative experiment. The researches on the application of atomic-emission spectroscopy method with inductively coupled plasma as a comparative method were conducted. In addition, the trueness control of the obtained results is confirmed by added-found method.
本文介绍了高分辨率连续光源石墨炉原子吸收光谱法在通过自行研发的含硫、氮杂链聚合物吸附剂进行分离和富集后测定铂、钯和铑的潜力。研究了废陶瓷基汽车尾气催化剂的样品制备方法，采用了其中两种方法：在盐酸：硝酸（3:1）混合酸中进行高压釜分解以及与焦硫酸钾进行高温熔融。无论采用哪种方法，都限制了通过高分辨率连续光源石墨炉原子吸收光谱法直接测定分析物。使用第一种方法时，废汽车尾气催化剂样品消化不完全，因为沉淀是硅，铑金属难以溶解且部分进入溶液。与第一种方法不同，第二种方法能使分析物完全转移到溶液中，然而，助熔剂化学成分产生的背景信号与分析区域重叠。研究发现，废陶瓷汽车尾气催化剂中所含的铂、钯和铑可通过具有高吸附容量、选择性且耐稀酸的含硫、氮杂链聚合物吸附剂有效分离和富集。所选择的高分辨率连续光源石墨炉原子吸收光谱分析条件使我们能够以良好的计量特性测定铂、钯和铑。在两个汽车尾气催化剂样品中，铂、钯和铑的浓度分别在0.00015 - 0.00050；0.170 - 0.189；0.0180 - 0.0210wt%范围内。通过高分辨率连续光源石墨炉原子吸收光谱法获得的相对标准偏差不超过5%。高分辨率连续光源石墨炉原子吸收光谱法实现的检测限分别为：铂6.2·10(-6)wt%、钯1.8·10(-6)wt%、铑3.4·10(-6)wt%。高分辨率连续光源石墨炉原子吸收光谱法实现的测定限分别为：铂1.1·10(-5)wt%、钯6.9·10(-5)wt%、铑8.3·10(-5)wt%。为了通过高分辨率连续光源石墨炉原子吸收光谱法控制吸附浓缩物中铂族金属（PGM）的准确性，进行方法间对比实验是合适的。开展了以电感耦合等离子体原子发射光谱法作为对比方法的应用研究。此外，通过加标回收法确认了所得结果的准确性。
