Highly sensitive determination of uric acid in the presence of major interferents using a conducting polymer film modified electrode

This paper describes the sensitive and selective determination of uric acid (UA) in the presence of important interferences, ascorbic acid (AA), dopamine (DA), tyrosine (Tyr) and methionine (Met) at physiological pH using an electropolymerized film of 3-amino-5-mercapto-1,2,4-triazole on glassy carbon (p-AMTa) electrode. The p-AMTa electrode shows an excellent electrocatalytic activity towards UA. This was understood from the observed higher oxidation current and heterogeneous rate constant (3.24 × 10− 5 m s− 1) for UA when compared to bare GC electrode (4.63 × 10− 6 m s− 1). The selective determination of UA in the presence of 1000-fold excess of AA was achieved using p-AMTa electrode. Further, the p-AMTa electrode was successfully used for the simultaneous and selective determination of UA in the presence of important interferences, DA, Tyr and Met. Using amperometric method, 40 nM UA was detected for the first time. The current response of UA was increased linearly while increasing its concentration from 40 nM to 0.1 mM and a detection limit was found to be 0.52 nM (S/N = 3). Finally, the practical application of the present method was demonstrated by determining UA in human urine and blood serum samples.

Simultaneous determination of dopamine (DA), uric acid (UA), tyrosine (Tyr) and methionine (Met) was achieved by voltammetry using 3-amino-5-mercapto-1,2,4-triazole polymer film modified glassy carbon electrode.Figure optionsDownload as PowerPoint slideHighlights
► Poly(3-amino-5-mercapto-1,2,4-triazole) film was used to determine uric acid.
► Selective determination of UA was achieved in the presence of 1000-fold AA at pH 7.2.
► Simultaneous determination of dopamine, UA, tyrosine and methionine was achieved.
► A detection limit of 5.15 × 10− 10 M (S/N = 3) was achieved for UA.
► UA concentration was determined from human urine and serum samples.