▎ 摘　　要

NOVELTY - Rapid detection of hexavalent chromium ion involves: (S1) using ascorbic acid reduction method to wrap palladium nanoparticles on the surface of dendritic nano-gold to obtain dendritic gold-doped palladium nanomaterial; (S2) modifying the nanomaterial on a surface of graphene oxide-thiol to obtain graphene oxide/gold-doped palladium; (S3) stirring the obtained product and a solution containing mercury ion, and centrifuging to obtain graphene oxide/gold-mercury doped palladium-mercury; (S4) mixing the product obtained in step (S3) with deionized water, tetramethylbenzidine (TMB) and hexavalent chromium ion to form a catalytic reaction system, reacting, taking mixed liquid, dripping on a tin foil, subjecting to Raman test, and drawing a standard working curve; and (S5) pre-processing hexavalent chromium ion sample of unknown concentration to be tested before testing according to the requirement of the national standard, and calculating chromium ion concentration in sample to be tested. USE - The method is useful for rapid detection of hexavalent chromium ion in base layer. ADVANTAGE - The method: provides graphene oxide/gold-mercury doped palladium-mercury as catalyst, which has excellent dispersibility and stability, and can synergistically catalyze TMB; is carried out under mild reaction conditions, safe and environmentally-friendly; and enables rapid and high sensitive detection of hexavalent chromium ions in base layer. DETAILED DESCRIPTION - Rapid detection of hexavalent chromium ion involves: (S1) using ascorbic acid reduction method at room temperature to wrap palladium nanoparticles with a particle size of 1-10 nm on the surface of dendritic nano-gold to obtain a product as dendritic gold-doped palladium nanomaterial; (S2) modifying the nanomaterial on a surface of graphene oxide-thiol by forming gold-sulfur and palladium-sulfur, centrifuging, washing the resulting product with deionized water, suspending in an equal volume of citric acid-disodium hydrogen phosphate buffer solution to obtain product as graphene oxide/gold-doped palladium; (S3) gently stirring the product obtained in step (S2) and a solution containing divalent mercury ion at room temperature for 20-30 minutes, centrifuging, and suspending in an equal volume of deionized water to obtain product as graphene oxide/gold-mercury doped palladium-mercury; (S4) mixing the product obtained in step (S3) with deionized water, tetramethylbenzidine (TMB) and hexavalent chromium ion to form a catalytic reaction system, reacting for 1-2 minutes, taking a portion of the mixed liquid, dripping on a tin foil, subjecting to Raman test with portable Raman spectrometer, taking hexavalent chromium ion concentration as the abscissa, corresponding intensity change of the Raman peak of the TMB oxidation product at 1608 cm-1 as ordinate, and drawing a standard working curve for quantitative analysis; and (S5) pre-processing hexavalent chromium ion sample of unknown concentration to be tested before testing according to the requirement of the national standard, using the method in step (S4) to detect the intensity change value of the corresponding Raman peak at 1608 cm-1, calculating the hexavalent chromium ion concentration in the sample to be tested according to the working curve and the national standard limit, and judging whether the hexavalent chromium ion content in the sample exceeds the standard.