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Article: Calcium phosphate solubility: The need for re-evaluation
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TitleCalcium phosphate solubility: The need for re-evaluation
 
AuthorsPan, HB1
Darvell, BW1
 
Issue Date2009
 
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/crystal
 
CitationCrystal Growth And Design, 2009, v. 9 n. 2, p. 639-645 [How to Cite?]
DOI: http://dx.doi.org/10.1021/cg801118v
 
AbstractThe determination of the solubility of calcium phosphates by the conventional large excess of solid method has been demonstrated to be inappropriate. The problem lies in incongruent dissolution, leading to phase transformations, and lack of detailed solution equilibria: all calculations have been based on simplifications, which are only crudely approximate. The absolute solid-titration approach shows excellent reliability and reproducibility. Using solid titration, the true solubility isotherm of hydroxyapatite (HAp) has been found to lie substantially lower than previously reported. In addition, contrary to wide belief, dicalcium phosphate dihydrate (DCPD) is not the most stable phase below pH ∼4.2, where calcium-deficient HAp is less soluble. The misunderstanding here arises from the metastability of DCPD, which nucleates much more easily than HAp at low pH. Such results indicate that the Ca-P system is in need of complete reappraisal. The solid-titration method can be extended to other complex systems. © 2009 American Chemical Society.
 
ISSN1528-7483
2012 Impact Factor: 4.689
2012 SCImago Journal Rankings: 1.358
 
DOIhttp://dx.doi.org/10.1021/cg801118v
 
ISI Accession Number IDWOS:000263048200001
 
ReferencesReferences in Scopus
 
DC FieldValue
dc.contributor.authorPan, HB
 
dc.contributor.authorDarvell, BW
 
dc.date.accessioned2011-11-02T03:06:30Z
 
dc.date.available2011-11-02T03:06:30Z
 
dc.date.issued2009
 
dc.description.abstractThe determination of the solubility of calcium phosphates by the conventional large excess of solid method has been demonstrated to be inappropriate. The problem lies in incongruent dissolution, leading to phase transformations, and lack of detailed solution equilibria: all calculations have been based on simplifications, which are only crudely approximate. The absolute solid-titration approach shows excellent reliability and reproducibility. Using solid titration, the true solubility isotherm of hydroxyapatite (HAp) has been found to lie substantially lower than previously reported. In addition, contrary to wide belief, dicalcium phosphate dihydrate (DCPD) is not the most stable phase below pH ∼4.2, where calcium-deficient HAp is less soluble. The misunderstanding here arises from the metastability of DCPD, which nucleates much more easily than HAp at low pH. Such results indicate that the Ca-P system is in need of complete reappraisal. The solid-titration method can be extended to other complex systems. © 2009 American Chemical Society.
 
dc.description.naturelink_to_subscribed_fulltext
 
dc.identifier.citationCrystal Growth And Design, 2009, v. 9 n. 2, p. 639-645 [How to Cite?]
DOI: http://dx.doi.org/10.1021/cg801118v
 
dc.identifier.doihttp://dx.doi.org/10.1021/cg801118v
 
dc.identifier.eissn1528-7505
 
dc.identifier.epage645
 
dc.identifier.hkuros163517
 
dc.identifier.isiWOS:000263048200001
 
dc.identifier.issn1528-7483
2012 Impact Factor: 4.689
2012 SCImago Journal Rankings: 1.358
 
dc.identifier.issue2
 
dc.identifier.scopuseid_2-s2.0-61749093731
 
dc.identifier.spage639
 
dc.identifier.urihttp://hdl.handle.net/10722/143143
 
dc.identifier.volume9
 
dc.languageeng
 
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/crystal
 
dc.publisher.placeUnited States
 
dc.relation.ispartofCrystal Growth and Design
 
dc.relation.referencesReferences in Scopus
 
dc.titleCalcium phosphate solubility: The need for re-evaluation
 
dc.typeArticle
 
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Author Affiliations
  1. The University of Hong Kong