Simultaneous electrochemical detection of uric acid and ascorbic acid at a silver doped poly(glutamic acid) modified glassy carbon electrode

摘要

In this paper, the silver doped poly (L-glutamic acid) modified glassy carbon electrode (PLG-Ag/GCE) was fabricated through an electrochemical immobilization. The modified electrode was used for simultaneous determination of uric acid (UA) and ascorbic acid (AA) in 0.1 M phosphate buffer solutions (PBS). The cyclic voltammetric signals of UA and AA were well separated with a potential difference of 396 mV in pH 3.0 phosphate buffer solution. The linear calibration curves were obtained in the concentration range 5.00 × 10 ~(-7)-1.00 × 10~(-4) M for UA and 8.00 × 10 ~(-6)-5.00 × 10~(-3) M for AA with the detection limits of 3 × 10~(-7) M and 4 × 10~(-6) M, respectively. The relative standard deviations were 1.3 and 1.0% for the determi- nations of UA and AA for 20 continuous measurements. The signal was highly stable and reproducible. This method was successfully applied to the determination of UA in human urine samples.