Enrichment And Analysis Of Food Pigments By Ionic Liquids Coated Magnetic Nanoparticles In Magnetic Solid Phase Extraction Coupled With Spectrophotometry

Magnetic solid phase extraction?MSPE?is a kind of solid-phase extraction technique which is using magnetic or magnetizable material as absorbent matrix.In recent years,MSPE as a new mode of sample pretreatment method has attracted much attention.Compared with common solid-phase extraction technology,MSPE has many advantages including simple operation,short extraction time,low organic solvent consumption,and easy automation.It has a broad application prospect in food analysis,environmental analysis and pharmaceutical analysis.In MSPE method ionic liquid can be used as sorbents for extraction of different analytes.Ionic liquids?ILs?are a class of organic salts that possess unique chemical and physical properties,such as good stability,higher extraction efficiency and hydrophobic properties.These attractive properties make them promising materials for a number of analytical applications.1.Determination of Rhodamine B Pigment in Food Samples by Ionic Liquid coated Magnetic Core/shell Fe₃O₄@SiO₂ Nanoparticles Coupled with Fluorescence SpectrophotometryThree hydrophobic ionic liquids?ILs?1-octyl-3-methylimidazolehexafluorophosphate?[OMIM]PF₆?(1-butyl-3-methylimidazolehexafluorophosphate?[BMIM]PF₆?,1-hexyl-3-methyl-i midazole hexafluoro-phosphate?[HMIM]PF6?,were coated by Fe₃O₄@SiO₂ nanoparticles with core-shell structure to prepare magnetic solid phase extraction agents?Fe₃O₄@ SiO₂@[OMIM]PF₆?and establish a new method of magnetic solid phase extraction?MSPE?coupled with fluorescence spectrophotometery for determination of Rhodamine B.The results showed that Rhodamine B was adsorbed rapidly by Fe₃O₄@SiO₂@[OMIM]PF₆ and eluted by ethanol,the pre-concentration factor of the proposed method was 20-fold.Under the optimal conditions the linear range,detection limit?DL?,correlation coefficient?R?and relative standard deviation?RSD?were found to be 0.40-140.00 ?g L^-1,0.06 ?g L^-1,0.9998 and 0.45%(n=3,c=4.00 p,g L^-1,respectively.The proposed method has been successfully applied to the determination of Rhodamine B in food samples.2.Separation/Analysis of Congo red by using Poly Ionic Liquid Immobilized Magnetic Nanoparticles Magnetic Solid Phase Extraction Coupled with Fluorescence SpectrophotometryMagnetic solid phase extraction?MSPE?accompanied with fluorescence spectrophotometry using Poly?ionic liquid?immobilized magnetic nanoparticles?PIL-MNPs?as sorbents were introduced for congo red?CR?analysis in food.Poly?1-vinyl-3-butylimidazolium?bromide immobilized?MNPs?were prepared through co-polymerization of 1-vinyl-3-hexylimidazolium-based ionic liquid and vinyl-modified magnetic particles.Some of different types of parameters,such as pH value,adsorption temperature and time,sample volume,eluent type,were studied.Under the optimum conditions,the preconcentation factor for CR was 27.The linear range,detection limit?DL?,correlation coefficient?R?and relative standard deviation?RSD?were found to be 0.02-8.00 ?g/mL,3.4 ?g mL^-1,0.9992 and 4.20%(n=3,c=5.00 ?g mL^-1,respectively.The method had been successfully applied to the separation/analysis of congo red in real samples.3.Poly Ionic Liquid Immobilized Magnetic Nanoparticles as Sorbent Coupled with Fluorescence Spectrophotometry for Separation/Analysis of Allura redPoly?1-vinyl-3-butylimidazolium?bromide immobilized magnetic nanoparticles?PIL-MNPs?sorbent were introduced for magnetic solid phase extraction?MSPE?accompanied with fluorescence spectrophotometry for Allura red?AR?separation in food samples.The PIL-MNPs were used as adsorbent phases in MSPE.Different parameters,like pH value,adsorption temperature and time,sample volume,eluent type,volume and time were studied.This method introduced the linearity for AR in concentration range between 0.01-0.50 ?g mL,correlation coefficient?R?was 0.9993 and the limit of detection was found to be 0.002?g mL.The equations of calibration graph was A?Absorbance?= 0.04+0.13c(pg mL^-1.The method was successfully applied for separation/analysis of allura red pigment in candies and beverages samples with satisfactory results.4.Determination of Rhodamine B in Food Samples by Fe₃O₄@Ionic Liquids-P-Cyclodextrin Cross-Linked Polymer Solid Phase Extraction Coupled with Fluorescence SpectrophotometryFe₃O₄@lonic liquids P-cyclodextrin polymer?Fe₃O₄@ mono-6-deoxy-6-?1-ethyl-imidazolium?-?-cyclodextrin iodide polymer,ILs-?-CDCP?was prepared.A novel method based on Fe₃O₄@ILs-?-CDCP solid phase extraction coupled with fluorescence spectrophotometry for Rhodamine B?RhB?determination,was investigated.Results were shown that RhB was adsorbed on Fe₃O₄@ILs-?-CDCP and eluted with sodium dodecyl sulfate?SDS??1.0%?rapidly.Different parameters,such as pH,adsorption time and volume,eluent volume and time were studied.This method introduced linearity for RhB between 0.01-9.00 ?g/mL^-1,the limit of detection was 5.2 ng/mL^-1,correlation coefficient?R?was 0.9987 and the relative standard deviation?RSD?was 3.1%?n=3,c=4.00 ?g/mL?.The method was applied successfully for determination of RhB in real samples with satisfactory results.5.Amino Acid Ionic Liquid Coated Magnetic Core Fe₃O₄@SiO₂ Nanoparticles Coupled With UV Spectrophotometry for Separation/Analysis of Congo RedAmino acid ionic liquid coated magnetic core Fe₃O₄@SiO₂ nanoparticles?Fe₃O₄@SiO₂@AAIL?as a new magnetic adsorbent coupled with UV spectrophotometry for the separation/analysis of congo red was established.The properties and morphology of the Fe₃O₄@SiO₂@AAIL were characterized by FTIR,SEM and XRD.A comprehensive study of the parameters affecting the extraction and elution efficiency was optimized.Under the optimum conditions,This method introduced wide linear range of 15-350 ngmL^-1,the correlation coefficient was 0.9991,the detection limit was 0.37?g mL^-1?RSD = 5.1%?.The method had been successfully applied to the separation of congo red in real samples.