| 1. Fabrication of carbon nanoelectrode ensembles and selective voltammetric detection of uric acid in human serum and urineA simple, facile, one-step approach to fabricate nanoelectrode ensembles (NEEs) using an amphiphilic diblock copolymer, polystyrene-block-poly (acrylic acid) (PS-b-PAA) self-assembly on a glassy carbon electrode has been developed. The NEEs drastically suppressed the response of ascorbic acid (AA) and resolved the overlapping voltammetric response of uric acid (UA) and AA into two well-defined peaks with a large anodic peak difference (ΔEpa) of about 310 mV. The peak current obtained from differential pulse voltammetry (DPV) was linearly dependent on the UA concentration in the range of 0.25 to 50μM at neutral pH (PBS, pH = 6.86) with a correlation coefficient of 0.999, and the detection limit was 0.04μM (S/N = 3). The NEEs was applied to the voltammetric selective and sensitive detection of UA in the presence of high concentration of AA, owing to UA weak adsorption and fast electrochemical kinetics under the high mass transport and radial diffusion at the NEEs and in their specific micro-environment of the nanopores. The pores of the NEEs were inside full of carboxylic functional groups. These functional groups can participate in charge-based interactions in the neutral solution. And one possible chemical interaction could be the hydrogen bonding between the more acidic– H of the UA and the carboxyl group present in the nanopores. The NEEs has also been demonstrated to be applicable in the detection of UA in serum and urine samples with excellent sensitivity and selectivity. |
PDF Full Text Request