Study Of Graphene Oxide Incorporated And Synergistic Boronate Affinity Monolithic Chips

In the actual sample analysis,the matrix of the measured component is complex,especially for the low levels of components presenting in the sample matrix.Since the direct detection of the test substance can interfere with the accuracy of the results,the separation and enrichment of the test substance before detection is an essential step.Polymer monolithic column is a new type of extraction medium,which is widely used for separation and enrichment of sample.However,current polymer monolithic columns have some problems,such as small specific surface area,low extraction efficiency,poor specificity and non-specific adsorption.Therefore,it is important to develop a polymer monolithic column with excellent performance to achieve the separation and enrichment of samples.In this paper,two types of polymer monolithic columns were developed,and their preparations and applications were investigated.In the first part,a monolithic chip incorporated with carboxylated graphene oxide(GO-COOH)based on deep eutectic solvents(DESs)was developed.With assistance of DESs,GO-COOH with amino modification by p-aminostyrene(p AS)was dispersed successfully in pre-polymerization mixture in order to ensure the uniformity of the monolith.The systematic studies of the preparation parameters on the performance of the resulting monoliths were carried out,including the content of GO-COOH-p AS,the composition of DESs and the ratio of porogens.The resulting GO-COOH incorporated monolith was characterized by nitrogen adsorption,scanning electron microscopy,and transmission electron microscopy.The GO-COOH-doped monolithic chip can be used for solid phase extraction(SPE)of polycyclic aromatic hydrocarbons(phenanthrene,anthracene,fluoranthene,pyrene,benzo(a)anthracene,benzo(a)pyrene,dibenzo(a,h)anthracene and inden(1,2,3,-cd)pyrene).The recoveries were all higher than 90%,which was about twice as high as that of the monolithic chip prepared without GO-COOH.By comparing the SPE results with that of GO-COOH-free monolithic chip,better enrichment effects were demonstrated on the GO-COOH incorporated monolithic chip,providing an effective method for the pretreatment of PAHs.In the second part,a boronate affinity monolithic chip with improved affinity and selectivity for glycoproteins was prepared by using a mixed functional monomer of 3-aminopropyltriethoxysilane-methacrylic acid(APTES-MAA)and polyhedral oligomeric silsesquioxane(POSS).Then,3-(acrylamido)benzeneboronic acid was adopted as boronate affinity ligand,and ethylene glycol dimethacrylate as the crosslinker,and iso-propanol and octanol as binary porogens.The systematic studies of the preparation parameters on the performance of the resulting monoliths were carried out,including different types of monoliths,the content of AAPBA,APTES-MAA and POSS and the ratio of porogens.The synergistic effect of APTES-MAA and POSS warranted good affinity and selectivity for glycoproteins,which resulted in a number of attractive features including(a)a wide operation of p H range(from 5 to 8);(b)higher enrichment factors ranging from 19.3 to 20.6;(c)greater recoveries of glycoproteins between 95.8 and 107.1%;(d)lower relative standard deviations ≤ 4.2%.Compared to the corresponding APTES-MAA/POSS-free monolith,the new boronate material had 1.7-fold increased glycoprotein recovery from complex samples.Finally,the boronate monolith could enrich glycoproteins in 500-fold diluted serum samples.