ANALYTICAL LETTERS Vol. 36, No. 3, pp. 577–590, 2003 PHARMACEUTICAL ANALYSIS Electrochemical Determination of Dihydrocodeine in Pharmaceuticals J. M. P. J. Garrido, 1 C. Delerue-Matos, 1 F. Borges, 2 T. R. A. Macedo, 3 and A. M. Oliveira-Brett 4, * 1 CEQUP/Departmento Engenharia Quı´mica, Instituto Superior de Engenharia do Porto, Porto, Portugal 2 CEQOFFUP/Departmento Quı´mica Orgaˆnica, Faculdade de Farma´cia Universidade do Porto, Porto, Portugal 3 Faculdade de Medicina and 4 Departmento Quı´mica, Faculdade de Cieˆncias e Tecnologia Universidade de Coimbra, Coimbra, Portugal ABSTRACT Two analytical methods for the quality control of dihydrocodeine in commercial pharmaceutical formulations have been developed and compared with reference methods: a square wave voltammetric (SWV) method and a flow injection analysis system with electroche- mical detection (FIA-EC). The electrochemical methods proposed *Correspondence: A. M. Oliveira-Brett, Departmento Quı´mica, Faculdade de Cieˆncias e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal; Fax: þ351-239-835295; E-mail: brett@ci.uc.pt. 577 DOI: 10.1081/AL-120018246 0003-2719 (Print); 1532-236X (Online) Copyright & 2003 by Marcel Dekker, Inc. www.dekker.com