▎ 摘　　要

NOVELTY - Preparing chitosan/graphene oxide/diatomite composite material comprises (i) adding graphene oxide and diatomite to ultrapure water, sonicating, and stripping graphene oxide to obtain uniform graphene oxide-diatomaceous earth dispersion, (ii) adding chitosan to the dispersion, continuously stirring and fully mixing, (iii) hydrothermally reacting the resulting mixture, and (iv) cooling the mixture to room temperature, freeze-drying to obtain chitosan/graphene oxide/diatomite composite. USE - The composite material is useful for pre-processing tea pesticide residue (claimed). ADVANTAGE - The method: utilizes economical and easily available raw materials; is mild and simple, convenient for mass production; has good purifying effect on the tea base, high degree of automation; saves time and manpower; and improves detection efficiency. DETAILED DESCRIPTION - INDEPENDENT CLAIM are also included for: (1) use of chitosan/oxidized graphene/ diatomite composite material for pre-processing tea pesticide residue, comprising (a) taking chitosan/graphene oxide/diatomite composite material to obtain solid phase extraction purification column, (b) adding organic reagent in the pulverized tea leaves, extracting and centrifuging to obtain supernatant, (c) purifying the supernatant obtained in the step (b) by flowing through purification column obtained in the step (a), (d) purifying the filtration membrane and directly using instrumental analysis for determining accurate qualitative and quantitative pesticide residues; and (2) chitosan/graphene oxide/diatomite composite material obtained by above method.