▎ 摘　　要

NOVELTY - Method for preparing electrode involves (a) preparing reduced graphene oxide/gold nanocomposite material (RGO/Au), (b) preparing silicon dioxide nanospheres and cadmium telluride nanocomposite material (SiO2-CdTe), (c) dripping RGO/Au solution onto indium-tin oxide (ITO) electrode, and coating RGO/Au surface, (d) dripping e.g. cauliflower mosaic virus (CaMV) 35S promoter solution onto ITO-rGO/Au-probe1 surface, (e) dispersing probe 2/SiO2-CdTe in distilled water, coating ITO-rGO/Au-probe1-t-DNA surface with obtained mixture. USE - The method is useful for preparing electrode for photoelectrochemical detection of transgenic CaMV 35 S promoter (claimed). ADVANTAGE - The method shows detection limit of 0.017 pM. DETAILED DESCRIPTION - Method for preparing electrode involves (a) preparing reduced graphene oxide/gold nanocomposite material (RGO/Au), (b) preparing silicon dioxide nanospheres and cadmium telluride nanocomposite material (SiO2-CdTe), (c) dispersing RGO/Au in distilled water to obtain RGO/Au solution, dripping RGO/Au solution onto indium-tin oxide (ITO) electrode surface, drying coated ITO electrode surface, coating RGO/Au surface with tris(hydroxymethyl)aminomethane hydrochloride (Tris-HCl) buffer, drying coated RGO/Au surface, and washing and drying electrode surface to obtain ITO-RGO/Au-probe1, (d) dissolving target DNA cauliflower mosaic virus (CaMV) 35S promoter in Tris-HCl buffer, dripping droplets on ITO-rGO/Au-probe1 surface, incubating at room temperature, and washing and drying electrode to obtain ITO-RGO/Au-probe1-t-DNA, and (e) adding distilled water dispersion liquid of SiO2-CdTe and aqueous solution of N-hydroxysuccinimide to ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, reacting, centrifuging the mixture to obtain solid (A), washing solid (A), adding solid (A) to Tris-HCl buffer solution with probe 2 to obtain mixture (A), performing reaction under oscillating condition to obtain solid product of probe 2/SiO2-CdTe, dispersing probe 2/SiO2-CdTe in distilled water to obtain mixture (B), coating ITO-rGO/Au-probe1-t-DNA surface with mixture (B), incubating, washing and drying electrode surface to obtain ITO-RGO/Au-probe 1-t-DNA-probe 2/SiO2-CdTe.