In order to characterize the reproducibility of the PAIUCPE, repetitive measurements were done for UA (5.0 × 10−5 mol/L) and FA (5.0 × 10−5 mol/L) mixture. The relative standard deviations (R.S.D.) of oxidation peak currents for them were 1.13% and 2.51% (n = 7), respectively, which indicated that the PAIUCPE had a better reproducibility. It was attributed to the thin reaction interface of the PAIUCPE, which made it difficult for the analyte to penetrate into the membrane, so it had no memory effect. After the PAIUCPE was stored at room temperature for 9 days, the oxidation peak currents decreased less than 5% (n = 7) of the initial signal which revealed a long-term stability.