Artículos de revistas
Potentiometric determination of L-ascorbic acid in pharmaceutical samples by FIA using a modified-tubular electrode
Registro en:
Journal Of The Brazilian Chemical Society. Soc Brasileira Quimica, v. 11, n. 2, n. 182, n. 186, 2000.
0103-5053
WOS:000088270400014
10.1590/S0103-50532000000200014
Autor
Fernandes, JCB
Rover, L
Kubota, LT
Neto, GD
Institución
Resumen
A flow injection system using a tubular electrode based on the redox properties of copper (II) ions occluded in EVA membrane was developed for L-ascorbic acid determination. The polyethylene-co-vinyl acetate (EVA 40% m/m) matrix was doped with copper (II) ions and dispersed on the surface of a graphite/epoxy tubular electrode. The electrode showed a super-Nernstian response for L-ascorbic acid concentration between 10(-3) and 10(-1) mol L-1 with a detection limit of 8.5x10(-4) mol L-1, when 0.1 mol L-1 KH2PO4 buffer mixed with 0.1 mol L-1 hydrogen peroxide at pH 5.0 was employed as carrier The Potentiometric-FIA system allows an analytical frequency of 120 samples per hour with a precision of 3.6%. The results obtained for ascorbic acid determination in pharmaceutical samples, without any previous treatment, were similar to these obtained by the British Pharmocopoeia method. 11 2 182 186