Photocatalytic Redox Reactions for In‐Source Peptide Fragmentation

Abstract

Top stuff: The configuration of tetrafluoromethane–water is driven by dipole–dipole interactions rather than hydrogen bonds. The complex, which consists of a planar and a spherical moiety, is an asymmetric top in its equilibrium conformation, but its effective behavior is that of a symmetric top, owing to its high internal dynamics.

Influence of Crystalline Forms of Titania on Desorption/Ionization Efficiency in Titania-Based Surface-Assisted Laser Desorption/Ionization Mass Spectrometry

“…6). Under the UV-laser irradiation on titania based SALDI-MS, it was reported that electrons are excited from the valence band to the conduction band of titania, producing oxidative holes to drive in-source oxidation reactions and reductive electrons to induce in-source reactions of analytes in SALDI-MS. 33), 48), 49) In this study, such UV-laser induced photocatalytic oxidation reactions were observed in the case of amorphous (or titania)-type titania with strong photocatalytic e#ects, but not for rutile-type titania with weak photocatalytic e#ects. As shown in Fig.…”

Biomarker Characterization by MALDI–TOF/MS

“…With this affinity strategy, selective enrichment of low-abundance biomolecules can be achieved. More recently, semiconductor nanomaterials and quantum dots were used as photosensitive centers to induce in-source redox reactions to investigate the oxidation of biomolecules [276,277]. Several nanomaterials have also been used as matrices in MALDI-TOF/MS analysis due to their low heat conductivities and light-absorbing capabilities.…”

Nanomaterial-Assisted Laser Desorption Ionization for Mass Spectrometry-Based Biomedical Analysis

“…During the investigation of photoinduced reductions, it was found that TiO 2 could also induce peptide regular fragmentation with the presence of glucose [31]. Specifically, glucose was oxidized by the holes, and the oxidized glucose could further oxidize the peptides and cleave the C a -C bond to generate a, x-fragments, as indicated in Figure 5.…”

“…TiO 2 semiconducting nanoparticles are widely used in the fi eld of phofield of phoof photocatalysis [29] and for the design of dye-sensitized solar cells. Under UV light irradiation, electrons in the valence band of TiO 2 can be excited into the conduction band, and both holes and electron can be trapped at the nanoparticle surface to form oxidative holes and reductive electrons able to react with surrounding molecules [30][31][32]. Using nano-TiO 2 to assist LDI, in-source redox reactions induced by these redox centers can be observed during the ionization processes [30][31][32].…”

“…�rimary studies on in-source redox reactions during NALDI include oxidation of ferrocene derivatives and reduction of organic dyes during DIOS [91][92][93]. Recently, we employed TiO 2 nanoparticle modinanoparticle modiparticle modified substrates to perform on-line redox reactions on biomolecules coupled with MS analysis [30][31][32]. The applications of this strategy involve on-line tagging of Cys residues by quinone compounds, in-source reduction of disulfide bonds in proteins and oxidation of peptides for a,x-fragmentation, as shown in Figure 5 [30][31][32].…”