title: Highly-sensitive electrochemical sensing platforms for food colourants based on the property-tuning of porous carbon.
abstract: It is very challenging to develop highly-sensitive analytical platforms for toxic synthetic colourants that widely added in food samples. Herein, a series of porous carbon (PC) was prepared using CaCO3 nanoparticles (nano-CaCO3) as the hard template and starch as the carbon precursor. Characterizations of scanning electron microscopy and transmission electron microscopy indicated that the morphology and porous structure were controlled by the weight ratio of starch and nano-CaCO3. The electrochemical behaviours of four kinds of widely-used food colourants, Sunset yellow, Tartrazine, Ponceau 4R and Allura red, were studied. On the surface of PC samples, the oxidation signals of colourants enhanced obviously, and more importantly, the signal enhancement abilities of PC were also dependent on the starch/nano-CaCO3 weight ratio. The greatly-increased electron transfer ability and accumulation efficiency were the main reason for the enhanced signals of colourants, as confirmed by electrochemical impedance spectroscopy and chronocoulometry. The prepared PC-2 sample by 1:1 starch/nano-CaCO3 weight ratio was more active for the oxidation of food colourtants, and increased the signals by 89.4-fold, 79.3-fold, 47.3-fold and 50.7-fold for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. As a result, a highly-sensitive electrochemical sensing platform was developed, and the detection limits were 1.4, 3.5, 2.1 and 1.7 μg L(-1) for Sunset yellow, Tartrazine, Ponceau 4R and Allura red. The practical application of this new sensing platform was demonstrated using drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography.
authors: Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
authors: Qin
authors: Q
authors: Cheng
authors: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Science, Beijing, 100190, China.
authors: Shanhong
authors: S
authors: Xia
authors: State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Science, Beijing, 100190, China.
authors: Jianhua
authors: J
authors: Tong
authors: Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China. Electronic address: kbwu@hust.edu.cn.
authors: Kangbing
authors: K
authors: Wu
mesh_terms: D001391:Azo Compounds / Q000032:analysis*; D001628:Beverages / Q000032:analysis*; D002244:Carbon / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D055664:Electrochemical Techniques / Q000379:methods; D004566:Electrodes; D005505:Food Coloring Agents / Q000032:analysis*; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D009282:Naphthalenesulfonates / Q000032:analysis*; D010084:Oxidation-Reduction; D016062:Porosity; D013645:Tartrazine / Q000032:analysis*
chemical_list: D001391:Azo Compounds; D005505:Food Coloring Agents; D009282:Naphthalenesulfonates; C005915:Allura Red AC Dye; D002244:Carbon; C005842:6-hydroxy-5-((p- sulfophenyl)azo)-2-naphthalenesulfonic acid disodium salt; D013645:Tartrazine; C576297:ponceau 4R
keywords: Food colourants; High sensitivity; Porous carbon; Property tuning; Sensing platform