NGHIÊN CỨU PHÁT TRIỂN ĐIỆN CỰC ĐĨA THAN THỦY TINH ĐƯỢC BIẾN TÍNH VỚI L–CYSTEIN VÀ VÀNGNANO CHO PHƯƠNG PHÁP VON–AMPE HÒA TAN ANOT XUNG VI PHÂNXÁC ĐỊNH AXIT URIC

Tóm tắt

    A new gold nanoparticles-modified electrode was fabricated by self-assembling gold nanoparticles to the surface of the L-cysteine-modified glassy carbon electrode (GC/L-cys/Au-nano). The modified electrode showed an excellent characteristicsfor differential pulse anodic stripping voltammetric (DP-ASV) determination of uric acid (UA) in 0.1 mol L-1 phosphate buffer solution (PBS) (pH = 4.1). The anodic currents of UA on the modified electrode were 12-fold to that of the bare GC. Kinetic parameters of the UA electrode process such as electron transfer coefficient (α) and electron transfer rate constant (Ks) were calculated. Influences of the factors such as pH, concentration of L-cysteine (L-cys), deposition potential (Edep) and time (tdep) on stripping current of UA were investigated. The DP-ASV with the modified electrode gained high sensitivity (1.49 µA/µM), low detection limit (2.7 µM at Edep = +200 mV and tdep = 20 s) and good linerrange in the UA concentration of 2.0 - 40µM. The proposed method was successfully applied for the detection of UA in human urine and serum samples(without the samples treatment)with satisfactory results: good accuracy with recovery of 108 - 126% and good repeatability with relative standard deviation (RSD) of 1.2 - 2.7% (n = 3).
Keywords: Uric acid, DP-ASV, Gold nanoparticles, L-cysteine.