Naslov
The influence of some amino acids on calcium oxalate dihydrate transformation

Autori
Kralj, Damir ; Brečević, Ljerka

Izvornik
Journal of crystal growth (0022-0248) 79 (1986), 1/3; 178-184

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
calcium oxalate ; amino acids

Sažetak
The influence of histidine (His), serine (Ser), tryptophan (Trp), glutamic acid (Glu) and ornithine (Orn) on the formation of calcium oxalate hydrates and the transformation of calcium oxalate dihydrate (COD) to the thermodynamically stable monohydrate (COM) has been studied. Simultaneous production of two hydrates (COM and COD) was initiated by mixing sodium oxalate solutions containing the respective amino acid with equal volumes of calcium chloride solutions. A combination of optical microscopy, X- ray diffraction, thermogravimetric analysis, size distribution measurements and atomic absorption spectroscopy were used to characterize the processes involved. The examined amino acids have a specific effect on the nucleation of calcium oxalates: Trp and His promote the formation of COD over COM while the others favour the formation of COM. The presence of Trp and Ser influenced the morphology of COD crystals. The processes comprising the transformation, the dissolution of COD and the growth of COM, were examined separately. The corresponding growth and dissolution rates have been determined and it was found that Trp and Ser affected the transformation kinetics by changing the rate controlling mechanism of COD dissolution from diffusion to a surface controlled reaction.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA