Preparation And Performance Study Of Seven-membered Cucurbitacin-trimeric Indenesin Type Functional Molecule Capillary Gas Chromatography Stationary Phas

Cucurbit [n] uril materials have attracted extensive attention in the field of gas chromatography stationary phase research due to their special structure and molecular recognition ability.In this paper,based on 4-vinylbenzyloxy cucurbit [7] uril(4-VBOQ[7]),a cucurbit [7] uril-trimeric indene star-type functional molecule(Q[7]-Tr)was synthesized by coupling reaction.The compound has good solubility in organic solvents such as dichloromethane and chloroform,breaking the bottleneck of cucurbit[7] uril insoluble in conventional organic solvents and limited application in gas chromatography.At the same time,Q[7]-Tr capillary chromatographic column was prepared by static method with Q[7]-Tr as the stationary phase.The morphology,thickness and thermal stability of the column coating were characterized.The basic performance and separation performance of Q[7]-Tr column were investigated.The main results are as follows :Q[7]-Tr combines the unique molecular recognition ability of cucurbit [n] urils and the rigid plane and π-electron delocalization structure of triindene.As a fixed phase guest molecule,Q[7]-Tr has multiple retention mechanisms,including the cavity hydrophobic interaction of cucurbit [n] urils,ion-dipole interaction,hydrogen bonding interaction,and π-π interaction and dispersion interaction of triindene.The results showed that the coating thickness of Q[7]-Tr chromatographic column was about 0.3μm,and the morphology was dense and uniform.Thermogravimetric curve shows that the Q[7]-Tr stationary phase has only 5 % mass loss when the temperature reaches339 °C,and the Q[7]-Tr stationary phase has high stability.The average polarity of Q[7]-Tr column was 126,which belonged to the medium weak polarity stationary phase.The optimum flow rates of naphthalene and n-dodecane on Q[7]-Tr column were about19.3 cm/s and 16.1 cm/s,respectively,and the corresponding maximum column efficiencies were 5961 n/m and 5857 n/m,respectively.The Q[7]-Tr column had good repeatability and durability.The RSD of inter-column repeatability was ≤ 1.64 %,and the RSD of inter-batch repeatability was ≤ 2.71 %.The interval between two tests of the same sample reached 126 days,and the RSD of retention time of various analytes was still less than 1 %.The Q[7]-Tr column has excellent separation effect on alkanes,esters,ketones,aldehydes,alcohols,9 positional isomers,Grob reagents,22 complex mixtures,halogenated benzenes,BTEX and plasticizers,and has better separation effect than the commercial column HP-5.In addition,the thermodynamic parameters of Q[7]-Tr column separation probe molecules were explored by using alcohols and PAHS as probe molecules.It was found that the retention of alcohols and PAHS on Q[7]-Tr column was controlled by enthalpy change and entropy change,and enthalpy change had a great influence.The physicochemical properties of Q[7]-Tr stationary phase and its excellent separation ability for various mixtures make it have great potential as a new type of high-performance capillary gas chromatographic column stationary phase material.