Matrix-Assisted Laser Desorption Ionization Mass Spectrometry of Compounds Containing Carboxyl Groups Using CdTe and CuO Nanoparticles

• Published in: Applied sciences 2018-03, Vol.8 (4), p.492
• Main Authors: Sakurai, Megumi, Sato, Taro, Xu, Jiawei, Sato, Soichi, Fujino, Tatsuya
• Format: Article
• Language: English
• Subjects: Angiotensin II; Cadmium telluride; carboxyl group; Desorption; Electrons; Fatty acids; Ionization; Ions; Lasers; MALDI; Mass spectrometry; Mass spectroscopy; Molecular weight; Nanoparticles; Neutralization; Peptides; Photoexcitation; Quantitative analysis; Quantum dots; Scientific imaging; semiconductor; Silicon; Stearic acid; Zeolites
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app8040492

[...]CdTe nanoparticles were loaded on a zeolite surface to improve reproducibility of the peak intensity, and the complex of CdTe and zeolite was applied to the quantitative analysis of stearic acid in human serum. Because it is understood that electrons ejected from CdTe nanoparticles react with carboxyl groups in fatty acids, we assumed that other compounds containing carboxyl groups could be ionized as well. [...]charge neutrality of the system was kept even after the photoexcitation and it was assumed that the buffer action of a Tyr molecule unlikely occurred, yielding a moderately intense peak (Figure 2f). [...]the concentration of the CdTe matrix was changed to 4 mg/mL in order to increase the number of electrons that could react with Tyr, and MALDI MS of Tyr was re-examined. The peak intensity of [Tyr−H]− was increased compared with that in Figure 2e, although the intensities of the other peaks were also increased. [...]it might be possible to consider that the deprotonation of Tyr was promoted as a large number of electrons that could overcome neutralization were generated from CdTe nanoparticles at 4 mg/mL. [...]it was verified that the strong electrostatic binding between CdTe and AngII prevented efficient desorption, and the peak intensity of AngII-related species became low.