Differential Pulse Voltammetric Determination of Selenocystine and Selenomethionine Using SAM nanoSe⁰/Vc/SeCys‐Film Modified Au Electrode

Abstract

The SAM nanoSe 0 /Vc/SeCys-film modified Au electrode has been prepared to determine selenocystine and selenomethionine. The AFM and SEM showed the special three-dimensional (3D) network structure of the sol-gel films. The affinity between nanoparticles and biomolecules created special chemical characters analyzed by the XRD and fluorescence. The modified electrode was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The modified films partly had resistance in the charge transduction of Fe(CN) 4À=3À 6 , but the less electron-transfer resistance. Differential pulse voltammetric (DPV) determination of selenoamino acids using SAM nanoSe 0 /Vc/SeCys-film modified Au electrode was presented. In PBS (pH 7.0) þ 0.1 mol L À1 NaClO 4 solution, selenoamino acids yielded a sensitive reduction peak at about þ 400 AE 50 mV. The peak current had a linear relationship with the concentration of selenoamino acids in the range of 5.0 Â 10, and a 3s detection limit of selenoamino acids was 1.2 Â 10 À8 mol L À1. The relative standard deviation of DPV signals of 0.50 Â 10 À6 mol L À1 selenoamino acids was 3.8% (n ¼ 8) using the same electrode and was 4.4% (n ¼ 5) when using three modified electrodes prepared at different times. The content of selenoamino acids in the organo-selenium powder were determined by DPV. The results showed 71.5 mg g À1 of SeCys and 65.1 mg g À1 of SeMet in the organo-selenium powder.

Voltammetric behavior of selenocystine at modified gold substrates

“…Over the past decade, the behavior of selenium-containing amino acids on gold and gold-modified electrodes has been explored [28][29][30][31][32]. Both selenomethionine and selenocysteine have been shown to adsorb onto gold substrates, the latter of which was proposed to form a self-assembled monolayer that supports diffusion controlled electron transfer to ferricyanide [28,30].…”

A Spherical Nucleic Acid Probe Based on the Au–Se Bond

“…It has been reported that selenium offers a better electronic match for the gold surface than usually used sulfur and the bond energy of Au–Se is higher than that of Au–S, indicating that the Au–Se bond is easier to form and is more stable in biothiol microenvironments. Although selenium-containing compounds are harder to obtain, Au–Se bond-based assemblies as new functional materials hold great potential, such as self-assembled monolayers, Au electrodes, Au nanoclusters, and Au nanoparticles, − which have been applied in the detection of biomolecules, cancer treatment, and other interesting applications. Therefore, Au–Se bond-based probes may offer new opportunities for innovation in the investigation of various biological events.…”