Synthesis of triclinic calcium pyrophosphate crystals
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This paper presents a method for preparing crystals of triclinic calcium pyrophosphate (t-CPPD). A calcium pyrophosphate intermediate is first prepared by reaction of potassium pyrophosphate and calcium chloride. Samples of the intermediate are dissolved in hydrochloric acid and urea added. Upon heating to 95–100 °C, hydrolysis of the urea causes the pH to rise and t-CPPD crystallises out. Purity of the product was ascertained by chemical and physical analysis. Where large crystals are required an unstirred system is used, while smaller crystals are produced by stirring the reaction mixture.
KeywordsMandel Rietveld Refinement CPPD Pseudogout Octacalcium Phosphate
We thank Mrs M Marshall for carrying out the ion chromatography. The work was funded by a Project Grant from the Arthritis Research Council. Dr Wilson was supported by grant G9505593MA from the Medical Research Council of the U. K. Dr Shellis thanks Glaxo SmithKline PLC for financial support.
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