Multi-channel electroanalysis of As (III), Hg and Cu in the complex matrix of Bombyx batryticatus after pre-purification

•A multi-channel electro-analysis technique was developed in animal matrix.•The complex matrix influence was weakened by four different removal methods.•The effective working area distinctly enhanced 6.98% by modified AuNPs.•As, Cu and Hg were synchronously screened within 3 min in one run.•The validated method is sensitive, fast, accurate and stable for trace analysis of heavy metals.