Article: Calcium phosphate solubility: The need for re-evaluation
| Title | Calcium phosphate solubility: The need for re-evaluation |
|---|---|
| Authors | Pan, HB1 Darvell, BW1 |
| Issue Date | 2009 |
| Publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/crystal |
| Citation | Crystal Growth And Design, 2009, v. 9 n. 2, p. 639-645 [How to Cite?] |
| Abstract | The 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. |
| ISSN | 1528-7483 2011 Impact Factor: 4.72 2011 SCImago Journal Rankings: 0.279 |
| References | References in Scopus |
| dc.contributor.author | Pan, HB |
|---|---|
| dc.contributor.author | Darvell, BW |
| dc.date.accessioned | 2011-11-02T03:06:30Z |
| dc.date.available | 2011-11-02T03:06:30Z |
| dc.date.issued | 2009 |
| dc.description.abstract | The 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.nature | link_to_subscribed_fulltext |
| dc.identifier.citation | Crystal Growth And Design, 2009, v. 9 n. 2, p. 639-645 [How to Cite?] |
| dc.identifier.eissn | 1528-7505 |
| dc.identifier.epage | 645 |
| dc.identifier.issn | 1528-7483 2011 Impact Factor: 4.72 2011 SCImago Journal Rankings: 0.279 |
| dc.identifier.issue | 2 |
| dc.identifier.scopus | eid_2-s2.0-61749093731 |
| dc.identifier.spage | 639 |
| dc.identifier.uri | http://hdl.handle.net/10722/143143 |
| dc.identifier.volume | 9 |
| dc.language | eng |
| dc.publisher | American Chemical Society. The Journal's web site is located at http://pubs.acs.org/crystal |
| dc.publisher.place | United States |
| dc.relation.ispartof | Crystal Growth and Design |
| dc.relation.references | References in Scopus |
| dc.title | Calcium phosphate solubility: The need for re-evaluation |
| dc.type | Article |
Author Affiliations
- The University of Hong Kong