Data-dependent acquisition based high-resolution mass spectrum for trace Alternaria mycotoxin analysis and sulfated metabolites identification.

Alternaria mycotoxins are food-related compounds that are mainly produced by Alternaria fungi species. However, it's difficult for Alternaria mycotoxins analysis, especially for conjugated metabolites in food safety surveillance. In this work, a novel data-dependent acquisition (DDA) full mass scan and products scan protocol was proposed for qualitative and quantitative analysis of five target mycotoxins in tomato samples using ultra-high-performance liquid chromatography coupled with quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap). In total, 24 sulfated metabolites were detected with post-data analysis techniques, and two sulfated metabolites (AME-sulfated and AOH-sulfated) were identified in Alternaria fungi -inoculated tomatoes. In addition, a custom database was established, and it was successfully applied for Alternaria mycotoxins and sulfated metabolites screening in tomatoes. With the improvement in high-resolution mass spectrometry (HRMS) as well as post-data analysis techniques, DDA based HRMS method could be widely applied for compound analysis, identification, and screening in quantitative field.

Permanganate release from silica-based hollow mesoporous coagulant combined with UV for spatiotemporal enrichment and degradation of diclofenac sodium.

In this work, the novel hollow mesoporous coagulant was prepared by chitosan-polydopamine coating and permanganate loading into silica nanoparticles for investigating the simultaneous enrichment and degradation of diclofenac sodium (DCFS) combined with ultraviolet irradiation. The enrichment kinetic of DCFS was explained well with pseudo-second-order model, indicating the exist of hydrogen bonding. Based on the correlation coefficients, the enriched isotherms were fitted by models which accorded with the BET > Freundlich > Langmuir sequence. The result showed that, in addition to the coagulant and DCFS, there were aromatic stackings among DCFS molecules. Due to both effects of which, the DCFS enrichment could be realized significantly in the range of pH 4.0-9.0. It was degraded at the copresence of ultraviolet and permanganate released from coagulant in acidic aqueous medium. The release mechanism was simulated through Korsmayer-Peppas model, implying case-II transport and Fickian diffusion. Additionally, Mn (V) and •OH radicals were vital in the DCFS degradation process. The coagulant could be reloaded at least ten times and that from each cycle was used directly for DCFS removal for six times without rinse process, which provided a potential application in environmental remediation.

Visible Post-Data Analysis Protocol for Natural Mycotoxin Production.

Fungal natural products are routinely analyzed using target detection protocols by comparing to commercial standards. However, discovery of new products suffers from a lack of high-throughput analytical techniques. Post-data process techniques have become popular tools for natural product confirmations and mycotoxin family analysis. In this work, a visible post-data process procedure with MZmine, GNPS, and Xcalibur was used for efficient analysis of high-resolution mass spectrometry. Conjugated products were screened with an optimized diagnostic fragmentation filtering module in MZmine and further confirmed with Xcalibur by comparing to unconjugated commercial standards. MS/MS spectral data were processed and used to establish a feature based on a molecular networking map in GNPS (Global Natural Products Social Molecular Networking; https://gnps.ucsd.edu), for visualization of fungal natural product families. The results demonstrate the potential of combining MZmine-, GNPS-, and Xcalibur-based methods for visible analysis of fungal natural products.