Ti-based MOF nanosheets as a mass spectrometry imaging matrix for low molecular weight compounds to reveal the spatiotemporal content changes of hepatotoxic components during the processing of Polygonum multiflorum

The selection of the matrix is crucial for matrix assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). This work successfully synthesized metal-organic framework (MOF) matrices to address the limitations on the application of traditional organic matrices in the study of small molecule compositions, and Ti-based MOF nanosheets were screened as matrices for imaging the hepatotoxic components of Polygonum multiflorum. Comparison between six MOF materials and traditional organic matrices showed that Ti-based MOF nanosheets have less background interference, significant stability, and high salt resistance. The imaging results indicated that the main components of Polygonum multiflorum, free anthraquinone and stilbene glycoside have unique spatial distribution characteristics. Successful application of the synthesized Ti-based MOF nanosheets in mass spectrometry imaging improved the detection ability of mass spectrometry imaging in the small molecule field, and spatiotemporal content changes of hepatotoxic components in Polygonum multiflorum during the steaming process were observed, providing a scientific basis for steaming.