This work describes the techniques of construction and several applications of ultramicroelectrodes in electrochemistry and electroanalytical chemistry. Disc shaped UME are produced by embedding metal wires on insulating materials such as glass or epoxy resin. In the field of electrochemistry, UME have been applied in studies of the hydrogen evolution reaction and the electrocrystallization of metals. The negligible values of sensibility for ohmic drop and the enhanced mass transport rate by spherical diffusion are the main advantages of UME in these applications. New important conclusions regarding the phenomena under study were drawn from the experimental results. The applications in electroanalytical chemistry involved the determination of contaminants such as heavy metals and nitrites in natural waters and food products. The use of UME requires little sample manipulation and, in general, no need for oxygen removal or the addition of supporting electrolytes.

Ainda são raros os dados sobre a infecção pelo vírus da hepatite C (HCV) na região central do Brasil. Neste estudo, 2.350 doadores voluntários de sangue foram avaliados, resultando em prevalências para o anti-HCV de 2,2%, pelo ELISA de segunda geração, e de 1,4%, após o ensaio confirmatório "line immunoassay". Anticorpos contra os antígenos "core", NS4 e NS5 do HCV foram detectados em 81,8%, 72,7% e 57,5% das amostras positivas no "line immunoassay", respectivamente. A viremia do HCV foi observada em 76,6% dos doadores anti-HCV positivos. A positividade na reação em cadeia da polimerase (PCR) mostrou-se relacionada a reatividade aos diferentes antígenos do HCV no "line immunoassay". A maioria dos doadores positivos tiveram história prévia de exposição parenteral. A combinação de ALT> 50 UI/l e positividade ao anti-HBc parece não ser eficaz como marcadores indiretos para a infecção pelo HCV, entretanto a dosagem do ALT e a detecção de anti-HCV são indicadas na triagem de doadores de sangue brasileiros.

Data concerning HCV infection in Central Brazil are rare. Upon testing 2,350 voluntary blood donors from this region, we found anti-HCV prevalence rates of 2.2% by a second generation ELISA and 1.4% after confirmation by a line immunoassay. Antibodies against core, NS4, and NS5 antigens of HCV were detected in 81.8%, 72.7%, and 57.5%, respectively, of the positive samples in the line immunoassay. HCV viremia was present in 76.6% of the anti-HCV-positive blood donors. A relation was observed between PCR positivity and serum reactivity in recognizing different HCV antigens in the line immunoassay. The majority of the positive donors had history of previous parenteral exposure. While the combination of ALT>50 IU/l and anti-HBc positivity do not appear to be good surrogate markers for HCV infection, the use of both ALT anti-HCV tests is indicated in the screening of Brazilian blood donors.