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|Type:||Artigo de periódico|
|Title:||Potentiometric sensor for L-ascorbic acid based on EVA membrane doped with copper(II)|
|Abstract:||The development of a new potentiometric sensor for L-ascorbic acid based on the redox properties of copper(II) ions incorporated in a EVA membrane was carried out. The poly(ethylene-co-vinyl acetate) matrix (EVA 40 % wt.) was doped with CU2+ ions and dispersed on the surface of a graphite/epoxy electrode. The electrode displayed a Nernstian response (slope between 55 and 60 mV/decade), in the ascorbate concentration between 5.6 x 10(-6) and 3.7 x 10(-4) mol L-1, when 0.1 mol L-1 KH2PO4 buffer at pH 5.0 and 25.0 degrees C was employed. The sensor stability was assessed, allowing 280 determinations without significant decrease in the response. The relative standard deviation for vitamin C determination in pharmaceuticals samples by the proposed method was about 10%. Considering these deviations, the results obtained for both the methods (spectrophotometric and potentiometric) were similar.|
|Editor:||Wiley-v C H Verlag Gmbh|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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