Citation
Lu, Hongbo B.; Campbell, Charles T.; Graham, Daniel J.; & Ratner, Buddy D. (2000).
Surface Characterization of Hydroxyapatite and Related Calcium Phosphates by XPS and TOF-SIMS.
Anal Chem, 72(13), 2886-2894.
Abstract
The surfaces of six biologically interesting calcium phosphate (CaP) phases (hydroxyapatite, dibasic calcium phosphate dihydrate, dibasic calcium phosphate, monobasic calcium phosphate, ?-tribasic calcium phosphate, octacalcium phosphate) have been examined by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The intensity of an O(1s) shake-up satellite correlates with the phosphate oxygen content. Together with the Ca/P and O/Ca XPS peak ratios, this feature helps provide identification of the CaP phase(s) present in the surface of unknown samples and establish their mole fractions, as proven with a bone sample. Contributions from carbonate impurities can be quantified using its C(1s) peak at 279.9 eV and subtracted from the O(1s) line shape to aid identification. Principal component analysis (PCA) has been applied successfully to analyze TOF-SIMS spectra of these six CaP phases. Multivariate analysis can help differentiate these CaP phases using the first two PCs, which are dominated by the relative intensities of only a few key ions:? PO3-, O-, Ca+, CaOH+, PO2-, and OH-.
Reference Type
Journal Article
Secondary Title
Anal Chem
Author(s)
Lu, Hongbo B.Campbell, Charles T.Graham, Daniel J.Ratner, Buddy D.
Year Published
2000
Date Published
962409600
Volume Number
72
Issue Number
13
Pages
2886-2894
DOI
10.1021/ac990812h
