A Rationally Designed Thymidine‐Based Self‐Assembled Monolayer on a Gold Electrode for Electroanalytical Applications

As elf-assembled monolayer (SAM) of 1-(3,5-epidi- thio-2,3,5-trideoxy-b-d-threo-pentofuranosyl)thymine (EFT) on ag old electrode wa sp repared and characterized by Raman spectra la nd electrochemical measurements. Voltam- metric and electrochemical impedance measurements show that the SAM of EFT on aA ue lectrode impedes the elec- tron-transfer reaction. The SAM of EFT was successfully used for the voltammetric sensing of urate in neutra ls olution. The coexisting ascorbate anion does not interfere and there- fore the EFT-based electrode was able to quantify urate at the micromolar level in the presence of al arge excess amount of ascorbate. To demonstrate the practical applica- tions, the amount of urat ei nt wo different human serum samples was quantified by using the EFT-based electrode; the results are in good agreement with those determined by the clinical method. DFT calculations show that both ascor- bate and urate have noncovalent interactions including hy- drogen-bonding interactions with EFT.