It is quite important to separate and enrich the target compounds from complicated sample matrices by suitable sample preparation techniques prior to the chromatography analysis.Development of online sample preparation techniques has attracted great attention.The high surface area makes graphene a promising material for use in sample prepraration[1].As a low-polarity material,graphene is not suitable to polar compounds extraction in the aqueous phase.Therefore,functional graphene are crucial.In this work,some online sample preparation methods based on functional graphene sorbents for online trace analysis of complicated samples were developed.