| In recent years, nano-materials, which have advantages of small particle size, large specific surface area, high surface reactive activity, good catalytic activity and strong adsorptivity, have attracted considerable attention. Self-assembly technology is an available method for preparation of new nano-materials modified electrodes.In this paper, the electrodes modified with nano-Au, which prepared by self-assembly technology, were constructed. Their structure and electrochemical properties were investigated. The modified electrodes have been successfully applied for the determination of glucose, absorb acid and formaldehyde. The major contents of the paper have been described as follows:Part one Determination of glucose using Ag electrode modified with nano-AuGold colloid were firstly prepared: With string, 100 ml of 0.01 % HAuCl4 aqueous solution was heated to a boiling condition, then 2 ml of 1 % trisodium citrate was rapidly added. Then a carefully cleaned Ag electrode was dipped into the gold colloid to obtain the non-enzymatic glucose sensor by self-assembly technology. The result showed that the nano-gold modified electrode had good current response to glucose in alkaline medium. The oxidation current was linearly related to the concentration of 2.00×10-7～1.75×10-4 mol/L with a detection limit of 1.50×10-7 mol/L.Part two Determination of ascorbic acid on nano gold–L- alanine Compound modified glass carbon elelctrodeNano gold-L-alanine modified GCE was constructed by layer self-assembly technology. The electrocatalytic behavior of ascorbic acid on this modified electrode was studied. The result showed that the electro-catalytic activity is markedly enhanced for ascorbic acid oxidation on the modified electrode. The oxidative peak current of ascorbic acid is linear to the concentration of ascorbic acid ranging from 1.20×10-5 to 1.60×10-4 mol/L with a detection limit of 1.00×10-5 mol/L.Part three Catalytic oxidation of formaldehyde on nano gold– valine compound modified elelctrodeNano gold - valine modified electrode was prepared by layer self-assembly technology and the electro-catalytic oxidation properties for formaldehyde on the modified electrode in alkaline medium have been investigated. The electro-catalytic activity is markedly enhanced for formaldehyde oxidation on the modified electrode, which is attributed to the cooperation between nano-gold - valine and glass carbon electrode. The electro-catalytic oxidation current had good linear range for formaldehyde with concentrations from 1.00×10-5 to 1.60×10-2 mol/L and the detection limit was 8.20×10-6 mol/L. So this modified electrode can be developed as a rapid, sensitive electrochemical detection method for formaldehyde.
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