Lyophilized histidine investigated using X-ray photoelectron spectroscopy and cryogenics: Deprotonation in vacuum
2005 (English)In: JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, Vol. 148, no 2, 96-100 p.Article in journal (Refereed) Published
Lyophilized histidine samples were investigated using X-ray photoelectron spectroscopy (XPS). Lyophilized samples were prepared from aqueous solutions at a pH in the range between similar to 1.5 and similar to 10, and with no further addition of electrolyte. The use of cryogenics allowed the determination of protonated to unprotonated molar ratios of sites in L-histidine, which correlates well with the dissociation constants of the residual amino acid sites. When cryogenics was not used deprotonation of the lyophilized samples occurred, where the degree and the total concentration of deprotonated sites correlates well with the formation constants and the decrease in Cl concentration, respectively. This later relation clearly indicates a correlation between deprotonation and the desorption of HCl from lyophilized samples. (c) 2005 Elsevier B.V. All rights reserved.
Place, publisher, year, edition, pages
2005. Vol. 148, no 2, 96-100 p.
histidine, XPS, formation constant, deprotonation
IdentifiersURN: urn:nbn:se:umu:diva-13058DOI: doi:10.1016/j.elspec.2005.04.002OAI: oai:DiVA.org:umu-13058DiVA: diva2:152729