Easy fabrication of aminated graphene oxide functionalized magnetic nanocomposite for efficient preconcentration of phenolic acids prior to HPLC determination: Application in tea-derived wines.

In this study, aminated graphene oxide functionalized magnetic nanocomposite (AGMN) was facilely synthesized by one-pot hydrothermal approach and acted as the extraction phase of magnetic solid phase extraction (MSPE) of phenolic acids (PAs). Characterization results revealed that the AGMN possessed satisfying saturation magnetism and abundant functional groups. Under the optimal extraction parameters, the proposed AGMN/MSPE presented high enrichment capability to PAs. Sensitive and dependable method for measurement of PAs in wine was proposed by the combination of AGMN/MSPE and HPLC/DAD. Limits of detection and limits of quantification were in the ranges of 0.031-0.23 μg/L and 0.10-0.78 μg/L, respectively, and the RSDs for approach precision varied from 1.8% to 8.9%. Recoveries at low, medium and high fortified levels varied from 84.6% to 116%. The suggested method was used to quantify investigated PAs in ten kinds of Tieguanyin tea-derived wines, and found the contents of PAs in wines were related to the quality of tea-leaves and alcohol content.