▎ 摘　　要

NOVELTY - Preparation of polydiallyldimethylammonium chloride (PDDA)-graphene hybrid nano-modified material, involves adding graphene oxide dispersion, PDDA, and hydrazine hydrate to water, stirring and reacting at 90-100 degrees C, centrifuging, washing, and drying. The ratio of PDDA and graphene oxide is 2-4:1 mL/g, preferably 3.2:1 mL/g. The ratio of hydrazine hydrate and graphene oxide is 4-8:1 mL/g, preferably 6.4:1 mL/g. USE - Preparation of PDDA-graphene hybrid nano-modified material for electrodes used in preparation of electrochemical sensors used for detecting monoamine neurotransmitters, and in preparation of microfluidic device (all claimed). ADVANTAGE - The method enables simple preparation of hybrid nano-modified material having excellent dispersibility, large specific surface area, strong conductivity, and excellent biocompatibility. The material provides electrodes high in sensitivity and good in selectivity, with wide linear range and low detection limit, and which is convenient to use. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) electrode comprising the hybrid nano-modified material provided on a base electrode; (2) microfluidic device; and (3) preparation of microfluidic device.