▎ 摘　　要

A glassy carbon electrode (GCE) was modified with a nanocomposite synthesized from electropolymerized L-cysteine (poly L-cys), gold nanoparticles (AuNPs), and B, N co-doped reduced graphene oxide (B, N-RGO). The sensor is depicted to enable the individual and simultaneous voltammetric determination of two purine derivatives, uric acid (UA) and xanthine (XA). Under the optimal conditions, the sensor displayed a good linear relationship between 3.0 nM and 3.0 mu M for UA and 0.3 nM and 3.0 mu M for XN in simultaneous determination. The limit of detection (LOD) and sensitivity are estimated to be 0.9 nM and 1.908 mu A mu M-1 cm(-2), for UA and 90.0 pM and 0.846 mu A mu M-1 cm(-2) for XA, respectively. The modified GCE demonstrates several benefits, including high sensitivity and selectivity, low LOD, high surface-to-volume ratio, and good electrocatalytic activity towards UA and XA. The sensor was used successfully for the simultaneous measurement of UA and XA in human blood serum samples.