Fluorescent Carbon Dot Probe For Rapid Detection Of Potassium Ferrocyanide In Salt And Pickled Products

Ferricyanide,including sodium ferricyanide(Na4[Fe(CN)6]),potassium ferricyanide(K4[Fe(CN)6]),and calcium ferricyanide(Ca2[Fe(CN)6]),are 23 commonly used in table salt as anticaking agents to keep salts loose and fluid.According to the GB2760-2014 "Food Additives Use Standard" issued by the National Health and Family Planning Commission of China,potassium ferrocyanide is an anti-cementation agent allowed to be added in salt and salt products in China,but the added amount should not exceed 10 mg/kg.In ferrous cyanide,the chemical bond between the cyanide group and the iron atom is strong,so the toxicity itself is very low.However,ferrous cyanide decomposes at high temperatures to produce highly toxic cyanide,which can be converted to sodium cyanide/strong hydrocyanic acid under alkaline/acidic conditions and is harmful to human health.It has been reported that long-term low doses of ferrous cyanide can cause nervous system damage,Parkinson's disease,confusion and mental decline,and high doses can cause shortness of breath,fainting,loss of consciousness and even death.Therefore,it is very important to develop a fast,convenient,accurate and accurate analytical method to detect ferrous cyanide in food.This article discussed the consumption of glucose as carbon source,carbon quantum dots doped impurity atoms of different synthesis as ferrocyanide fast detection techniques of detection method is feasible,and its application in rapid detection of complex food matrix is feasible,for research and development and test strip ferrocyanide portable test instrument to provide feasibility analysis.(1)Nitrogen(N)and chlorine(Cl)double-doped carbon dots(N,Cl-CNPs)were successfully prepared by acid-base neutralization and autoexothermic reaction using glucose,EDA and HCl,which were bright blue under ultraviolet light.Potassium ferrocyanide has a strong quenching effect on the fluorescence of carbon dots.The experimental results show that the change of blue fluorescence intensity of N,Cl-CNPs is due to the dynamic quenching effect of FeCNs,rather than Na+,K+or Ca2+.The detection limit was 2206.00 ng/mL,and the concentration was in the range of 14.0-110.0 ?g/mL.This method is highly selective and anti-interference,and can be used for the specific quantitative detection of FeCNs in simulated real samples(including various possible interfering substances).This work provides a new possibility for the rapid detection of FeCNs by using carbon point probe for the first time.(2)By doping different elements in the carbon skeleton of the carbon dot,the specificity and sensitivity of the fluorescence detection of the carbon dot probe can be regulated.Although the mechanism of the doping of different elements on the detection performance of carbon dot probe has not been clearly concluded up to now,it is certain that the selection of different precursors to synthesize doped carbon dot can establish reliable data support for the rapid detection of FeCNs.In this part of the work,glucose,HCl,H2SO4 and EDA were used to synthesize N,S and Cl doped carbon point probes:N,S,Cl-CNPs.The bright blue fluorescence emitted by N,S,Cl-CNPs excited by ultraviolet light can be strongly quenched by FeCNs,and the quenching principle is dynamic quenching.This method is highly selective and anti-interference,and can be used for the specific quantitative determination of FeCNs in complex food substrates.Carbon point probes based on N,S,Cl-CNPs have two linear ranges(0.01-1.00 ?g/mL and 1.00-50.00 ?g/mL)for the detection of FeCNs,and the detection limits are 3.30 and 21.80 ng/mL,respectively.It provides more possibilities for the detection of ferrous cyanide by carbon point probe method.(3)In order to study which element doped carbon point probe has a better effect on the detection of FeCNs,in this part of the work,glucose,H2SO4 and EDA were used to synthesize N and S doped carbon point probe(N,S-CNPs).FeCNs has a strong fluorescence quenching effect and can be used to quantitatively determine the content of FeCNs in complex food matrix.N,S-CNPs probe for real-time quantitative detection of FeCNs has three discontinuous linear ranges in the range of 0.01-200.00 ?g/mL FeCNs,and the minimum detection limit is 2.80 ng/mL.By comparing the detection performance of the three carbon points synthesized in this paper,the N,S-CNPs based carbon point probe detection method has a wider linear range and a lower detection limit for FeCNs detection.Therefore,N,S-CNPs were applied in the actual sample detection in this paper,and compared with the national standard method.The results show that the N,S-CNPs based carbon point probe detection method can be applied to the rapid detection of FeCNs in food samples.