The Functionalized Material Modified By Anionic Polyelectrolyte Selectively Adsorbs Cationic Dyes

In recent years,the detection of illegal industry cationic dyes has been the hot spot in food safety testing area.The illegal cationic dyes can't be directly detected in the instrument due to the low concentrations and impurity interference in actual sample.The pre-treatment of the solid phase extraction is a kind of common method in sample testing.The intended of this paper is to synthesize a series functionalization adsorption materials which had good selectivity,high adsorption capacity,easy to operate and synthesis.This paper includes the following four parts:Chapter 1 ReviewThis chapter primarily introduces the types,pre-treatment method and detection method of illegal cationic dyes in food.Then this chapter also introduces the background and application fields of polyelectrolyte of doped porous carbon materials and Metal-Organic Frameworks.Chapter 2 The synthesis and characterization of functionalized nitrogen doped magnetic porous carbon materials.The experiment of this chapter used double metal template method to synthesize nitrogen doped magnetic porous carbon materials(NMPC).The reactants,which has agar as carbonsource,FeCl3 and Zn(NO3)2 as template agents,CTAB or melamine as nitrogensource,was dissolved in ultrapure water.The mixture was became NMPC by stirred,dried,calcinated and washed.Then the nitrogen doped magnetic porous carbon materials were modified by poly(sodium 4-styrenesulfonate)as NMPC-1-PSS and NMPC-2-PSS.And NMPC-1-PSS and NMPC-2-PSS had large specific surface area,negative charges of surface and good magnetic via varous characterization techniques(FT-IR,FE-SEM,FE-TEM,Nitrogen adsorption-desorption isotherms,Zeta potentials and magnetic measurements).Chapter 3 Selective adsorption of illegal cationic dyes with functionalization of nitrogen doped magnetic porous carbon materialsNMPC-1-PSS and NMPC-2-PSS had large negative charges of surface,specific surface area and are able to be rapidly separated from mixed solution under the magnetic field.NMPC-1-PSS and NMPC-2-PSS were applied to adsorb illegal cationic dyes.The solution pH,adsorption time and ionic strength were optimized.Under optimized conditions,the NMPC-1-PSS adsorption capacities were 30.04 mg/g for RB,155.50 mg/g for PA,102.85 for AO,117.00 for B21 and 116.70 mg/g for B22;the NMPC-2-PSS adsorption capacities were 18.81 mg/g for RB,136.74 mg/g for PA,73.16 mg/g for AO,100.92 mg/g for B21 and 63.63 mg/g for B22.NMPC-1-PSS and NMPC-2-PSS had excellent selective adsorption of illegal cationic dyes and were expected to used for pre-treatment process of illegal cationic dyes detection.Chapter 4 Selective enrichment and separation of illegal cationic dyes from foodstuffs with functionalization of metal-organic frameworksA novel adsorbent MIL-101(Cr)-PSS,poly(sodium 4-styrenesulfonate)(PSS)modified MIL-(Cr)-NH2,was successfully synthesized.MIL-101(Cr)-PSS has large specific surface area and negative charges of surface via characterization techniques of Nitrogen adsorption-desorption isotherms and Zeta potentials.It enables effective adsorption and separation of illegal cationic dyes,such as rhodamine B,pararosaniline,and auramine O,from foodstuffs prior to high performance liquid chromatography analysis.Under optimized conditions,good linearity was obtained over the concentration of 1.0?80.0 or 1.0?120 ng mL?1 with a correlation coefficient(R2)>0.999.Limits of detection and limits of quantification of the three dyes were 0.28-0.65 and 0.94-2.13?g kg-1 respectively.The recoveries of the three dyes in chili products,shrimp powder,bean products,and tomato sauce products were in the range of 86.8?119.3%,suggesting that the developed method is a promising tool for accurate quantification of the three dyes at trace levels in foodstuffs.