Gil R A, Ferrúa N, Salonia J A, Olsina R A, Martinez L D
Department of Analytical Chemistry, Faculty of Chemistry, Biochemistry and Pharmacy, National University of San Luis, Chacabuco and Pedernera, P.O. Box 375, 5700 San Luis, Argentina.
J Hazard Mater. 2007 May 8;143(1-2):431-6. doi: 10.1016/j.jhazmat.2006.09.051. Epub 2006 Sep 22.
An alternative and new system for on-line preconcentration of arsenic by sorption on a mini-column associated to hydride generation--inductively coupled plasma--optical emission spectrometry determination was studied. It is based on the sorption of arsenic on a column packed with ethyl vinyl acetate (EVA) turnings and the use of La(III) as co-precipitant reagent. This polymeric material was employed here for the first time as filling material for column preconcentration. It could work both as adsorbent and as sieve material. Sample and co-precipitant agent (lanthanum nitrate) were off-line mixed and merged with ammonium buffer solution (pH 10.0), which promoted precipitation and quantitative collection on the small EVA turnings. The arsenic preconcentrated by co-precipitation with lanthanum hydroxide precipitate was subsequently eluted with hydrochloric acid, which was the medium used for hydride generation. Considering a flow rate of 5 ml/min, three enrichment factors were obtained, 28-, 38- and 45-fold at three different sampling times, 60, 120 and 180s; respectively. The detection limits (3s) obtained for each case were 0.013, 0.009 and 0.007 microg/l. Additionally, the calculated precisions expressed as relatively standard deviation (R.S.D.) were 0.9, 1.3 and 1.1%. Satisfactory results were obtained for the determination of arsenic in standard reference material NIST 1643e Trace Elements in Water and drinking water samples.
研究了一种通过吸附在与氢化物发生相关的微型柱上进行砷在线预富集的新系统，并结合电感耦合等离子体发射光谱法进行测定。该系统基于砷在填充有醋酸乙烯酯（EVA）碎屑的柱上的吸附，并使用镧（III）作为共沉淀试剂。这种聚合材料首次被用作柱预富集的填充材料。它既可以作为吸附剂，也可以作为筛分材料。样品和共沉淀剂（硝酸镧）离线混合，并与铵缓冲溶液（pH 10.0）合并，这促进了沉淀并在小EVA碎屑上进行定量收集。与氢氧化镧沉淀共沉淀预富集的砷随后用盐酸洗脱，盐酸是用于氢化物发生的介质。考虑到流速为5 ml/min，在三个不同的采样时间60、120和180秒分别获得了28倍、38倍和45倍的三个富集因子。每种情况下获得的检测限（3s）分别为0.013、0.009和0.007 μg/l。此外，以相对标准偏差（R.S.D.）表示的计算精密度分别为0.9%、1.3%和1.1%。在标准参考物质NIST 1643e水中痕量元素和饮用水样品中砷的测定中获得了满意的结果。
