An electrochemical microsensor has been developed for the simultaneous assay of ascorbate (AA) and urate
(UA) antioxidants in human blood serum. The electrode surface was modified by means of electropolymerized conductive
poly(3,4-ethylenedioxythiophene) PEDOT organic films. Highly selective responses (detection potential difference more
than 250 mV) were obtained for both biomarkers by optimizing the PEDOT thickness. Contrary to most previous studies
the analytical performances were recorded by testing the microsensor directly in blood serum without any pretreatment of
the samples. Using differential pulse voltammetry (DPV) the sensitivity and detection limit were 0.481 μA μM-1 cm-2 and
4.2 μmol L-1 for AA and 1.815 μA μM-1 cm-2 and 2.0 μmol L-1 for UA. The calibration curves were linear in the
concentration range 5–200 μmol L-1 for AA and 3-700 μmol L-1 for UA. The accuracy of the sensor was satisfactorily
compared with the reference analytical methods provided that the synergic effect between both antioxidants was
considered. The sensor response was unmodified in the presence of the major biochemical interfering species.
Keywords: Antioxidants, ascorbic and uric acids, blood serum analysis, EC’ mechanism, electrochemical microsensor,
interfering species, PEDOT film, Oxidative stress, electropolymerization, μAu-PEDOT microsensor.
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Published on: 04 January, 2013
Page: [84 - 91]