A digital image-based flow-batch analyzer for determining Al(III) and Cr(VI) in water

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• 作者：Sté ; fani Iury E. Andrade ; Marcelo B. Lima ; Inakã ; S. Barreto ; Wellington S. Lyra ; Luciano F. Almeida ; Má ; rio C.U. Araú ; jo ; ^{laqa@quimica.ufpb.br} ; Edvan C. Silva
• 关键词：Digital images ; RGB color system ; Flow-batch analyzer ; Aluminum ; Chromium ; Water
• 刊名：Microchemical Journal
• 出版年：2013
• 出版时间：July, 2013
• 年：2013
• 卷：109
• 期：Complete
• 页码：106-111
• 全文大小：615 K

文摘

This study proposes a digital image-based flow-batch analyzer (DIB-FBA) for aluminum (III) and chromium (VI) determinations in natural water. A webcam with a CCD sensor and RGB data are used. The method for determining aluminum is based on an Al(III) ion, quercetin, and cetyltrimethylammonium bromide (CTAB) reaction which yields a yellow colored complex in an acetate buffer medium (pH 5.5). The determination of chromium is based on a Cr(VI) ion with 1,5-diphenylcarbazide (DPC) reaction whose product is a violet colored complex. Digital images present the color of the emergent (complementary) radiation to that absorbed by the complexes formed in each analysis. RGB data were employed to build the analytical curves. All standard solutions were prepared in-line, and all analytical processes were completed by simply changing the operational parameters in the DIB-FBA control software. The working ranges were from 10 to 600 ¦Ìg L^? 1 for Al(III) with r = 0.9994 (n = 5), and 10 to 300 ¦Ìg L^? 1 for Cr(VI) with r = 0.999 (n = 5), the limits of detection were 3.97 and 2.65 ¦Ìg L^? 1 respectively for Al(III) and Cr(VI). The relative standard deviation (RSD % ) and sampling rate were estimated at 1.5 % and 137 h^? 1 and at 1.7 % and 134 h^? 1 for Al(III) and Cr(VI), respectively. Comparing with the reference method, no statistically significant differences were observed when applying the paired t-test at a 95 % confidence level.