Selective photocatalytic degradation of poly(ethylene glycol) additives using TiO₂ surface‐assisted laser desorption/ionization mass spectrometry

Mass Spectrometry of Synthetic Polymers

“…The highly informative data provided by MALDI-TOF-MS allowed establishing the pathways of photolysis and photooxidation , . Watanabe et al applied TiO 2 -SALDI-MS for the analysis of PMMA in the presence of PEG (Figure ) . The use of TiO 2 nanoparticles combines the advantages of a selective photocatalytic degradation effect of PEG with those of a SALDI matrix for the desorption/ionization of PMMA when irradiated with the UV laser.…”

“…MALDI and SALDI-MS spectra of PEG6000 (average molecular weight 6000): (a) dithranol matrix without UV irradiation, m / z 500−8000; (b) TiO 2 nanoparticles without UV irradiation, m / z 500−8000; (c) TiO 2 nanoparticles with 30 s UV irradiation, m / z 500−8000; (d) TiO 2 nanoparticles without UV irradiation, m / z 1200−1300; and (e) TiO 2 nanoparticles with 30 s UV irradiation, m / z 1200−1300. Reprinted with permission from ref . 2009 Wiley Interscience.…”

Nanoparticle TiO2 Films Prepared by Pulsed Laser Deposition: Laser Desorption and Cationization of Model Adsorbates

“…For this model analyte, the threshold with the P25 NPs (7.5 µJ) was smaller than the one observed for the conventional 2,5-DHB matrix (10 µJ), corroborating the good LDI performance of TiO 2 reported in earlier works. 2,[8][9][10][11][12][13][14] Moreover, the 2,5-DHB matrix leads to a higher dispersion of the threshold data, as a consequence of the greater heterogeneity of the crystallized sample. Interestingly, relatively low thresholds for the Gly-His-Gly analyte were also achieved with at least two of the PLD substrates, namely, with the ns266A anatase substrate deposited with 266 nm nanosecond laser pulses (14 µJ threshold) and with the fs266 amorphous substrate produced with 266 nm femtosecond laser pulses (12 µJ threshold).…”

“…1,2,7 Previous investigations have demonstrated the feasibility of employing TiO 2 micrometric and nanometric particles to assist the LDI detection of low molecular weight adsorbates of different polarity. 2,[8][9][10][11][12][13][14][15] One main conclusion inferred from those studies is the relevance of the surface properties at the nanoscale for the efficiency of the laser desorption process. Nevertheless, the mechanistic background involved in the desorption and ionization stages is still largely unknown.…”

“…The band gap of TiO 2 lies within 3.0−3.2 eV, depending on its microscopic solid structure, making it also particularly suitable for near-ultraviolet laser desorption mass spectrometry. Surprisingly, the use of TiO 2 in this field is relatively recent, in contrast to the more developed mass spectrometric application of other semiconducting materials, such as silicon, carbon, and further mesoporous materials. ,, Previous investigations have demonstrated the feasibility of employing TiO 2 micrometric and nanometric particles to assist the LDI detection of low molecular weight adsorbates of different polarity. ,− One main conclusion inferred from those studies is the relevance of the surface properties at the nanoscale for the efficiency of the laser desorption process. Nevertheless, the mechanistic background involved in the desorption and ionization stages is still largely unknown.…”