Resumo

MARCOLINO-JR., Luiz H.; BONIFACIO, Viviane Gomes; FATIBELLO-FILHO, Orlando  e  TEIXEIRA, Marcos F. S.. Flow injection turbidimetric determination of dipyrone using a solid-phase reactor containing silver chloride immobilized in a polyester resin. Quím. Nova [online]. 2005, vol.28, n.5, pp. 783-787. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422005000500009.

A simple flow injection procedure was developed for determining dipyrone (1-phenyl-2,3-dimethyl-4-methylaminomethano-5-pyrazolone sodium, metamizol, analgin) in pharmaceutical formulations. The determination is based on the reduction of Ag⁺ ions to Ag⁰ by dipyrone. A colloidal suspension of Ag⁰ produced was transported by carrier solution (0.01 mol L^-1 NaOH) and turbidimetrically detected at 425 nm. The analytical curve for dipyrone was linear in the range from 5.0 x 10^-4 to 2.5 x 10^-3 mol L^-1 with a correlation coefficient of 0.9990. The detection limit was 1.3 x 10^-4 mol L^-1 (3s_B/slope). The relative standard deviation for ten successive measurements was 1.8% and an analytical frequency of 45 h^-1 was obtained. The recovery values from three samples ranged from 96.0 to 102%.

Palavras-chave : dipyrone; flow injection turbidimetry; solid-phase reactor.