Preparation method of compound modified electrode for simultaneously detecting lead and cadmium ions

The invention discloses a preparation method of a compound modified electrode for simultaneously detecting lead and cadmium ions. The preparation method comprises the following steps: preparing graphene; preparing nano graphene; preparing micro-nano carbon spheres; synthesizing a micro-nano carbon sphere, nano graphene and naphthol compound modification liquid; modifying a working electrode based on a micro-nano carbon sphere, nano graphene and naphthol compound modification liquid; and simultaneously detecting heavy metal lead ions and cadmium ions. When the modified electrode manufactured by the method is applied to a sensor, the simultaneous sensitive detection of heavy metal lead ions and cadmium ions with similar potentials is realized, the detection sensitivity and the detection speed can be effectively improved, and the detection limit is far lower than the minimum content requirement of the heavy metal lead ions and cadmium ions in drinking water; and the compound modified electrode is simple in structure, low in energy consumption, raw material cost, process cost and labor cost, excellent in mechanical property and chemical corrosion resistance, and capable of achieving the effects of saving energy, reducing emission, treating environmental pollution and guaranteeing life health, and the whole detection system is convenient to achieve miniaturization and automation.