▎ 摘　　要

In this work, a new procedure was investigated for the production of a reduced graphene oxide/gold nanoparticle (rGO/AuNP) nanocomposite for use as an ideally polarizable modifier in electrochemical sensors. Ethylenediamine (en) was used for reducing the active functional groups (epoxy and carboxylic) of graphene oxide (GO) and as a cross linker for the formation of AuNPs during chemical reduction with sodium citrate. The constructed nanocomposite (AuNP/en-rGO) was easily homogenized in dimethylformamide (DMF) and characterized using different techniques. AuNP/en-rGO was drop-cast on a screen-printed electrode (SPE) as an efficient electrochemical sensor for the highly sensitive determination of fenitrothion. The differential pulse voltammetry (DPV) response of the AuNP/en-rGO-modified SPE under optimized conditions was linear in the range of 0.1-6.25 ng mL(-1) with a limit of detection of 0.036 ng mL(-1) (S/N = 3). The AuNP/en-rGO-modified SPE showed a selective amperometry response toward fenitrothion among other interfering pesticides. In addition, the sensor was successfully employed for determining the fenitrothion residue in some water samples, including tap and lake waters, and the results were in agreement with those using gas chromatography as the standard test method.