Abstract: An electrochemical sensor was constructed by immobilizing graphene as a new nanomaterial and chitosan on glassy carbon electrodes. The electrochemical properties of benzo(a)pyrene were investigated? and a rapid and sensitive method for the detection of benzo(a)pyrene in vegetable oils was established. A well-defined oxidation peak was observed at 1.0 V according to the cyclic voltammogram of benzo(a)pyrene at the nano electrochemical sensor and no reduction peak appeared, indicating that this is an irreversible redox process. The experimental conditions for electrochemical detection of benzo(a)pyrene in vegetable oils were optimized as follows: 5 μL of a mixed solution of chitosan-graphene (1:2, V/V) was used as modified solution; the concentration of LiClO4 as electrolyte was 0.2 mol/L; sulfuric acid concentration was 0.1 mol/L; and the enrichment time was 15 min. Under these optimal conditions, there was a good linear relationship between the redox peak current of benzo(a)pyrene and its concentration in the range of 0–100 nmol/L ( Ip = 0.116 2 CBaP + 22.926 2, R2 = 0.997 8), and the limit of detection (LOD) was 0.103 nmol/L (RSN = 3). The recoveries of benzo(a)pyrene in spiked sesame oil were in the range of 98.51%–100.57%. The results well agreed with those obtained by high performance liquid chromatography. The proposed method had good stability and repeatability and was characterized by simple sample pretreatment, short detection time, rapidity and low cost.

Key words: benzo(a)pyrene, electrochemical sensor, food safety, vegetable oils