Paper Spray Mass Spectrometry Detection And Catalytic Reaction Based On Porous Materials

Porous materials have made great progress in chemical separation,adsorption and heterogeneous catalysis due to their rich pore structure,excellent specific surface area and good stability,its interdisciplinary combination with different analytical techniques is an inevitable trend of the development of the discipline.Paper spray mass spectrometry?PSMS?is a new ambient mass spectrometry technique using paper matrix as carrier for sample separation and ionization.However,a plenty of hydroxyl groups exist on the surface of the paper substrate.When analyzed with paper spray,target compounds is difficult to elute the target compounds in a short period of time,because of the hydrogen bonds or van der Waals interactions between the paper substrate and analytes.In addition,because the paper matrix is a kind of microporous material with small specific surface area,the adsorption capacity of the target analyte is weak,which further reduces the analytical capacity of the method.Therefore,the development of new paper substrates is of great important to improve the analytical performance of paper spray-mass spectrometry.In response to the problems of paper spray mass spectrometry and combining the advantages of porous materials,as a proof of concept,we combined covalent organic frameworks?COFs?with paper spray to establish COFs-based paper spray detection platform and applied it to organic pollutant detection.The cavity-limiting effect of the coordination cage can carry out some catalytic reactions,and the unique chemical reaction or mechanism of paper spray has been reported in the literature.It is a new topic to combine the coordination cage with paper spray.The combination of the two advantages with unique advantages may open up a new way for the research of some specific chemical reactions.The main work of this thesis includes the following:1?A new method of COFs-based paper solid phase microextraction?SPME?combined with PSMS was proposed,and it was applied for detecting organic pollutants.In this method,starch was used as the adhesive agent and COFs were modified on paper substrate by vacuum filtration.The optimal experimental conditions were obtained by exploring the factors of starch type,starch amount,COFs amount,solvent type and voltage,and then a quantitative analysis method for organic pollutants?Tetrabromobisphenol A?in water samples was established.The experimental results showed that the sensitivity of COFs-coated paper substrates is 50 times higher than that of uncoated paper substrates and has a lower limit of quantitation?LOQ?.At the same time,experiments have found that the prepared paper matrix has good repeatability and stability.The COFs material has high stability,porosity,high specific surface area,and excellent guest adsorption capacity,which greatly improves the detection capability of COFs-based paper spray mass spectrometry.This indicates that the COFs-coated paper substrate can be used as a novel substrate material in paper spray mass spectrometry.2?TPE nanocages based on Fe²⁺and Cu⁺were synthesized,and then applied to the synthesis reaction of 2,3-dihydroquinazolinone.Meanwhile,the catalytic activity and reaction kinetics difference of the two coordination cages were also investigated.The results show that,both Cu-TPE and Fe-TPE have good catalytic effect.Notebly,Fe-TPE has faster reaction rate and higher catalytic activity compared with Cu-TPE.This ascribed to the confined effect of the nano-coordination cage.Cavity is usful for the planar reaction substrates to enter the hydrophobic cavity easily and the non-planar reaction products escape from the cavity quickly.By changing different groups,the space and electronic properties of guest molecules can be regulated,and the absorption and release of guest molecules can be achieved,achieving the purpose of high activity and high selectivity,providing new ideas for the study of coordination cages in catalytic reactions.The catalytic reaction of coordination cage combined with paper spray mass spectrometry is still in progress.