Covalent Organic Framework Nanofilm-Assisted Laser Desorption Ionization Mass Spectrometry for Rapid Screening of Parabens in Personal Care Products

Rational: People are widely exposed to parabens in their daily life, but parabens are endocrine disrupting chemicals that pose a threat to human health. Therefore, establishing a rapid screening method to enhance monitoring of parabens is necessary. Herein, a covalent organic framework (COF) nanofilm-assisted laser desorption ionization mass spectrometry (LDI-MS) method was established to screen parabens in personal care products (PCPs).

Methods: TAPB-TFPB-COF nanofilm was synthesized on indium tin oxide (ITO) glass and used as LDI-MS substrates. To observe the practicability of TAPB-TFPB-COF nanofilm-assisted LDI-MS, the results of this method for analyzing small molecules such as parabens, estrogens, and bisphenols were compared with those of the conventional organic matrix 9-aminoacridine (9-AA), and the reproducibility and detection limit were further verified. Finally, the method was applied to screen parabens in PCPs.

Results: TAPB-TFPB-COF nanofilm-assisted LDI-MS analyzed small molecules such as parabens, estrogens, and bisphenols with higher mass spectral signals and cleaner mass spectral backgrounds compared with 9-AA. Meanwhile, the method analyzed methylparaben (MeP) with high reproducibility (RSD = 6.96%) and low detection limit (1.64 μM) and performed well for rapid screening of parabens in PCPs.

Conclusion: TAPB-TFPB-COF nanofilm-assisted LDI-MS for analyzing small molecules such as parabens, estrogens, and amino acids offered the advantages of rapid analysis, a clean background, and good reproducibility. The method was successfully applied to detecting parabens in PCPs, demonstrating the practical utility of LDI-MS based on TAPB-TFPB-COF nanofilm for analyzing parabens in complex samples.