Investigations into the crystallization of cobalamine and the influence of ionic impurities on crystal growth

This paper presents an experimental investigation on the crystallization of cobalamine (vitamin B12) under different operating conditions and crystallization methods. A systematic analysis of the effects of cooling rate, stirring speed and solvent on the metastable zone and quality of crystals is presented. Focused beam reflectance measurement probe is used for in situ particle size analysis. The process of crystallization is observed by FBRM. The influence of four typical ionic impurities (Na+, Mg2+, Ca2+, and Fe3+) on cobalamine crystallization is also studied. From the observation of crystals by SEM, it is clear that Fe3+ and Mg2+ have significant effect on crystal morphology, while Na+ and Ca2+ have a little.