title: Determination of dipyrone in pharmaceutical products by flow injection analysis with potentiometric detection.
abstract: This work describes an FIA potentiometric procedure for the quantification of dipyrone in pharmaceutical products. For the detector, a tubular electrode comprising a polymeric membrane containing tetraoctylammonium as an electroactive material (5% w/w), dibutylphtalate as a mediator solvent (65% w/w) and PVC (30% w/w) directly applied above a graphite conductor support was used. This unit was incorporated into a monochannel FI-system with a 0.1 mol/L phosphate buffer solution (pH = 5.2) as the carrier solution. The electrode showed a linear response from 8.0 x 10(-4) to 10(-1) mol/L dipyrone, a slope of 62.1 +/- 0.2 mV/dec in pH 5.2 units, an injection volume of 500 microL and a carrier flow-rate of 6 mL/min. This procedure was applied to the analysis of pharmaceutical formulations (oral and injectable) containing dipyrone; the obtained results gave a relative error of less than 3.9% and coefficients of variation less than 1% and 5%, respectively, for the FIA and classical iodometric methods.
authors.affiliation: Department of Chemical Engineering/Environmental Engineering and Quality Laboratory-UFPE, 50740-521-Recife, Brazil.
authors.forename: Jackson S
authors.initials: JS
authors.lastname: Albuquerque
authors.forename: Valdinete L
authors.initials: VL
authors.lastname: Silva
authors.forename: Fernando
authors.initials: F
authors.lastname: Lima
authors.forename: Alberto N
authors.initials: AN
authors.lastname: Araújo
authors.forename: Maria Conceição B S M
authors.initials: MC
authors.lastname: Montenegro
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis*; D004177:Dipyrone / Q000032:analysis*; D017022:Flow Injection Analysis; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011199:Potentiometry / Q000379:methods*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004364:Pharmaceutical Preparations; D004177:Dipyrone