Removal of multiple lipids from human plasma using a hydroxyl-functionalized covalent organic framework aerogel as a new sorbent.

A hydroxyl-functionalized covalent organic framework aerogel COF-aerogel was designed and prepared as an adsorbent for the removal of multiple lipids from human plasma. The applications of 1,3,5-tris(4'-hydroxy-5'-formylphenyl)benzene (THB) and 1,3,5-tris(4-aminophenyl)benzene (TAPB) as monomers, DMSO/mesitylene (v/v, 4/1) as reaction solvent, and n-propylamine as reaction regulator endow COF-aerogel with good adsorption performance for multiple lipids. The morphology, phase purity, specific surface area, pore size, surface charge, and stability of COF-aerogel were characterized. Adsorption thermodynamics and adsorption kinetics studies showed that COF-aerogel had high equilibrium adsorption capacities (> 15913 mg g) and fast adsorption equilibrium (≤ 10 s) for the four model lipids tested. COF-aerogel had good reusability with the removal of the model lipids being still more than 91% after 10 use cycles. The sample pretreatment conditions and adsorbent amounts used in lipids removal experiments were optimized. Under the optimized conditions, the method of ultra-high performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) using COF-aerogel as solid-phase extraction sorbent was validated with negligible matrix effects (0.4-3.0%) and good accuracy (86.7-110%) and was applied to determine  20 amino acids in human plasma samples from healthy individuals and gastric adenocarcinoma (GA) patients. The established method has been proved to have good application potential for the removal of multiple lipids in human plasma to reduce the matrix effects and improve the accuracy of clinical LC-MS analysis.