Nanoconfined liquid phase nanoextraction combined with in-fiber derivatization for simultaneous quantification of seventy amino-containing metabolites in plasma by LC-MS/MS: Exploration of lung cancer screening model

Targeted metabolomics with absolute quantification is widely applied in biomarker identification and drug screening. However, due to the complexity of biological matrix and trace amount of metabolites in plasma, simultaneous quantification of highly polar metabolites in plasma with broad coverage in short time is still challenging. Herein, we proposed a nanoconfined liquid phase nanoextraction (NLPNE) combined with in-fiber derivatization (IFD) strategy that enabled simultaneous quantification of seventy amino-containing analytes in plasma, including amines, nucleosides and their metabolites. Methanol−water (2:1, v/v) was selected as nanoconfined solvent (NCS) to quickly extract highly polar analytes based on the nanoconfinement effect, followed by IFD process directly performed by adding the derivatization reagent benzoyl chloride (BzCl) within 5 min. Besides saving time, this combination strategy was environment-friendly with little organic solvent consumption and cost-effective by using reusable carbon nanofibers. Furthermore, the sensitivity was increased up to 4.92-fold compared with protein precipitation (PP) based conventional derivatization method. Key factors that affected derivatization efficiency including the derivatization time, the amount of derivatization reagent, desorption solution and CNFs, were optimized by response surface methodology (RSM). After systematical method validation, this methodology was applied to determine the multi-metabolites index in plasma of lung cancer using an integrated data processing workflow. Then lung cancer diagnosis model was established through binary logistic regression analysis to make a reference for quick lung cancer screening clinically. Taken together, the NLPNE-IFD LC-MS/MS method for targeted metabolomics enables simultaneous quantification of seventy amino-containing analytes with advantages of broad coverage, high sensitivity, time- and solvent-saving, which could be used on cancer diagnosis clinically.