Journal
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
Volume 561, Issue 1-2, Pages 75-82Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jelechem.2003.07.003
Keywords
uric acid; ascorbic acid; fouling effect; flow injection analysis; cationic polymer film
Categories
Ask authors/readers for more resources
A polymer film of N,N-dimethylaniline (PDMA) having a positive charge on the quarternary ammonium group in its backbone was electrochemically deposited on a glassy carbon (GC) electrode surface. The resulting film-coated GC electrode was used to detect uric acid (UA) electrochemically in the presence of ascorbic acid (AA). Both UA and AA are anionic in a solution of pH 7 and thus were attracted to the film, which lowered their oxidation potentials and increased their oxidation currents. In cyclic voltammetric measurements, the negative shift of the oxidation potential of UA (by 0.28 V) compared with that at the bare electrode was larger than that of AA (by 0.2 V). Also the increase in the oxidation current of UA at the PDMA film-coated electrode was larger than that of AA. In square wave voltammetric measurements, the PDMA film-coated electrode could separate the oxidation peak potentials of UA and AA present in the same solution by about 200 mV though the bare electrode gave a single broad response. A successful elimination of the fouling effect by the oxidized product of AA on the response of UA has been achieved at the PDMA film-coated electrode. The detection limit of UA in the presence of 160-fold excess of AA was found as 1.25 muM and the current response for UA increased linearly with increase of its concentration from 1.25 to 68.75 muM in the presence of AA with a correlation coefficient of 0.999 and a sensitivity of 0.0276 muA muM(-1). In flow injection analysis, a good linear relationship between the oxidation current and the concentration from 2 to 21 muM of UA was found. The sensitivity of the PDMA film-coated electrode towards UA was calculated as 0.0285 muA muM(-1) with a correlation coefficient of 0.997. The stable and reproducible response for both AA and UA at the PDMA film-coated electrode was verified by flow injection experiments. As the response of UA was reproducible in the presence of AA, it was expected that the oxidized product of AA would not affect the electrode response of UA. Moreover, the physiologically common interferents (i.e., glucose, purine, urea and citrate) negligibly affected the response of UA. The PDMA film-coated electrode exhibited a stable and sensitive response to UA in the presence of interferents. (C) 2003 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available