Electrochemical Determination Of Pigment Addictives In Food

Quinoline yellow has been confirmed to be one of the synthetic colors which have detrimental effects on children's behavior,such as hyperactivity,irritability,impulsiveness,inattention,lack of basic social skills and self-control,as well as some neurological diseases.In this study work,a novel modified electrode based on polypyrrole(PPy)and single-walled carbon nanotubes(SWCNTs)was developed for the detection of quinoline yellow.Cyclic voltammetry(CV)and square wave voltammetry(SWV)were used to confirm the successful stepwise assembly procedure of the sensor.Under the optimal conditions,the fabricated electrode exhibits excellent electrochemical activity toward the oxidation of quinoline yellow.The liner range is from 0.8 to 100.0 ?M,and the detection limit is down to 0.08 ?M.The modified electrode also showed good accuracy,stability and reproducibility,which might be attributed to particular properties of polypyrrole,single-walled carbon nanotubes and synergic interaction between them.To enhance the sensitivity of electrochemical detection to quinoline yellow,the electrode modification material was improved.Polypyrrole has the ability to prevent the aggregation of single-walled carbon nanotubes,but it has no contribution to the conductivity of the material because of its ordinary conductivity.In the new modification material,graphene oxide was ued to disperse the carbon nanotubes,at the same time,ionic liquid([BMIM]PF6)was added to improve the conductivity of the electrode materials.Then a new electrode modified with ionic liquid/graphene oxide/carbon nanotube composite was constructed.Under optimal experimental conditions,the modified electrode exhibited two linear responses to quinoline yellow-0.5?10.0?M and 10.0?500.0 ?M with a low detection limit down to 0.04 ?M(S/N=3).It is obvious that,in the new electrode,the linear range of quinoline yellow became wider and the detection limit became lower.Undoubtedly,this modified electrode also showed good accuracy,stability and reproducibility.The electrode,modified with ionic liquid/graphene oxide/carbon nanotubes composite,was also used to study the electrochemical behavior of bright blue.Due to graphene oxide's dispersion ability to carbon nanotubes,excellent conductivity and fast electron transfer of the[BMIM]PF6,the modified electrode showed a significant electrochemical response to the oxidations of bright blue.Under optimal experimental conditions,the modified electrode exhibited two linear responses to bright blue-9.0 nM?1.0 ?M and 1.0?10.0 ?M with a low detection limit down to 4.0 nM(S/N=3).