New synthesis of self-assembly ionic liquid functionalized reduced graphene oxide–gold nanoparticle composites for electrochemical determination of Sudan I

•The ionic liquid functionalized RGO-AuNPs composites has been builded by a new route.•The ILRGO@AuNPs composites were employed in the sensitive determination of Sudan I in foods.•This new sensor exhibits lower detection limit for Sudan I (5.0 × 10− 11 M).

Positively charged gold nanoparticles (AuNPs) were self-assembled onto the surfaces of 1-allyl-3-methylimidazolium chloride (AMIM-Cl) functionalized reduced graphene oxide sheets (RGO) here. The AMIM-Cl functionalized RGO (ILRGO) loaded with AuNPs (ILRGO@AuNPs) modified glass carbon electrodes (GCEs) possess larger effective specific surface areas which can favor the adsorption of more Sudan I into the working electrode. So the ILRGO@AuNPs composites were successfully used for the fabrication of a facile and sensitive sensor for the determination of Sudan I. And the prepared sensor exhibits a broad linear range for Sudan I spanned 4 orders of magnitude from 1.0 × 10− 10 to 1.0 × 10− 6 M and a detection limit as low as 5.0 × 10− 11 M (S/N = 3). It is expected that this green sensor can be applied in the determination of other similar dyes.