Dopamine determinations under continuous flow conditions with a periodate-selective electrode

• Type: Article in International Scientific Journal
• Date: 1998

Authors

Lima, JLFC (Author) Other; Montenegro, MCBSM (Author) FFUP; Sales, MGF (Author) Other

Journal

Title: Journal de Pharmacie de Belgique

Vol. 53

Final page: 213

ISSN: 0047-2166

Publisher: Algemene Pharmaceutische Bond

Indexing

ISI Web of Knowledge

Scopus - 0 Citations

Other information

Authenticus ID: P-007-GE3

Abstract (EN): The present work reports the dopamine determination in pharmaceutical preparations, which are basically injections, in a flow injection analysis (FIA) system. The used method is based on an oxidation reaction with metaperiodate and a potentiometric detector. For this, a periodate-selective electrode with a tubular configuration, without an internal reference solution and with a membrane of metaperiodate bis(triphenylphosphoranylidene)ammonium (1.3%), 2-nitrophenyl octyl ether (67.5%) and PVC (31.2%) was constructed. This detector was inserted into a double-channel FIA manifold, comprising deionised water in the carrier stream and a 3×10-4 M metaperiodate sodium solution, prepared in a 6.6×10-2 M Na2SO4 solution for the ionic strength adjustment, in the confluent stream. By using a 7 ml/min flow rate, a 70 ¿L injection volume and a 50 cm reactor, a linearity range of potential vs dopamine concentration from 0.008 to 0.273 g/l, with a slope of ¿ 300 mV g l-1, and a reproducibility of ±0.4 mV, were achieved. Interference from common excipients as sodium metabisulphite, sodium chloride, glucose, polyethylene glycol, saccharose and fructose was evaluated performing recoveries over dopamine hydrochloride solutions with several concentration ratios of each possible interferent. Only a slight interference from sodium metabisulphite at 1:1 concentration ratio was recorded. The described system was used for dopamine determinations in injections, presenting a theoretical value of 200 mg/inj.. The average dopamine concentration of 25 determinations was 201.01 mg/inj., with a standard deviation of 3.33 mg/inj.. Recoveries were simultaneously performed over the previous determinations, and average and standard deviation of 101.02% and 1.45% were obtained, respectively.

Language: English

Type (Professor's evaluation): Scientific