Metal organic frameworks(MOFs) are characterized with high specific surface areas which are beneficial to adsorption,while Au nanoparticles(Au NPs) are known to have excellent catalytic activity.Therefore,the composites of Au NPs and MOFs have a wide application in electrochemical sensing.In this work,the composites of Au NPs@NU-901 were prepared and characterized by transmission electron microscopy,X-ray diffraction,infrared spectroscopy and X-ray photoelectron spectroscopy.The results obtained testified the successful synthesis of Au NPs@NU-901.The electrochemical performance of Au NPs@NU-901/GCE toward the electrocatalytic oxidation of butylated hydroxyanisole(BHA) was investigated by linear sweep voltammetry(LSV) and differential pulse voltammetry(DPV).The experimental results showed that Au NPs@NU-901/GCE could catalyze the electrochemical oxidation-reduction reaction of BHA,and the signal was enhanced more greatly compared with those of bare/GCE,NU-901/GCE and Au NPs/GCE.In addition,the oxidation mechanism of BHA was investigated by LSV.By exploring the relationship between peak potential and pH values ranging from 2.2 to 8.0,as well as the relationship among peak potential and peak currents and scanning rates ranging from 50 mV/s to 250 mV/s,it was proved that the oxidation-reduction reaction of BHA on Au NPs@NU-901/GCE exhibited a process involving two electrons and two protons.In order to improve the detection sensitivity,the conditions,including supporting electrolyte,drop-coating volume,accumulation potential and accumulation time,were optimized.Under the optimal conditions,an electrochemical sensor based on Au NPs@NU-901 was fabricated for the determination of BHA with a linear range of 0.10-50 μmol/L(r2=0.994 8) and a detection limit (S/N=3) of 0.049 μmol/L.The reproducibility of this method was evaluated by nine parallel trials with nine different electrodes,with a relative standard deviation (RSD) of 3.6%,indicating that a good reproducibility was obtained.The anti-interference performance of the sensor was also studied.Results showed that 5 000-fold K+,Na+,Cl-,citric acid and glucose,2 500-fold SO2-4,2 000-fold sucrose,8-fold tert-butylhydroquinone and 2-fold butylated hydroxytoluene produced no interference on the determination of BHA.To investigate the practical application value,the sensor was used to detect BHA in three kinds of biscuit samples.It was noteworthy that the results of samples obtained by this method were highly consistent with those obtained by high performance liquid chromatography,indicating a good accuracy.Furthermore,the recovery experiments for real samples at three concentration levels were carried out,and the recoveries were within the range of 95.6%-104%.The sensor was successfully applied to detect BHA in biscuit samples.Overall,the electrochemical sensor based on Au NPs@NU-901 composites,with good selectivity,sensitivity and accuracy for electrochemical oxidation of BHA,was successfully used in the quantitative determination of BHA in biscuit samples.This study provided a good demonstration for the application of noble metal nanoparticles and MOF composites in electrochemical field.