In Situ Construction of COF-Based Paper Serving as a Plasmonic Substrate for Enhanced PSI-MS Detection of Polycyclic Aromatic Hydrocarbons.

Abstract

Accurate detection, quantitation, and differentiation of polycyclic aromatic hydrocarbons (PAHs) and their isomers in diverse samples is elusive for paper spray ionization mass spectrometry (PSI-MS). To address these issues, herein, for the first time, we propose to fabricate a novel, flexible, and stable paper substrate based on covalent organic frameworks (COFs) via an in situ method under room temperature in air. After embedding gold nanoparticles (AuNPs), this paper substrate (COFs-paper) could further serve as a multifunctional plasmonic matrix (AuNPs-COFs-paper) for dual-wavelength laser-assisted PSI-MS detection of PAHs and feasible paper surface-enhanced Raman scattering (pSERS)-aided isomer discrimination. Taking advantage of the synergistic effect between the AuNPs and COFs present on the novel AuNP-embedded COFs-paper substrate, a satisfied LOD of 0.50 ng/μL for phenanthrene was realized, which improved almost 300 times compared with the naked-paper matrix, and the regression coefficient R2 was up to 0.999. Real sample corn oil-containing PAHs can be efficiently detected and identified using this technique. The established platform has promising potential for on-site chemical analysis with portable PSI-MS and pSERS instruments.