Highly sensitive detection of kinetin with electrochemical exfoliation of graphene nanosheets

In this work, we developed an efficient electrochemical exfoliation strategy for the preparation of graphene (eGr) nanosheets. Newly designed nanosheets-like eGr/GCE electrode possessed large specific surface area, low defect and good electrical conductivity, which facilitates the preconcentration of Kinetin (KT) onto the electrode surface. It exhibits a linear range extending from 0.5 to 100 µM and the lowest detection limit at 0.15 µM. The KT oxidation on eGr is an adsorption-controlled process, which involves a total of 4 H+ and 4 e− in the transferring processes. Moreover, there were no significant interfering substances among inorganics (NO3−, Cu2+, K+, PO43−, SO42−, Na+, Cl−), quercetin, rutin, luteolin, luteoloside, naphthylacetic acid, 2,4-dichlorophenoxyacetic acid and indole-3-acetic acid. The recoveries are in the range of 89.6–117.43% with a relative and deviation (RSD) < 4% (n = 3) for KT detection in lettuce.