Metastable zone of 5′-UMPNa₂ in ethanol-aqueous mixture

The dual circuits laser detector was used to measure the solubility and super-solubility of uridine-5′-monophosphate disodium salt in the ethanol-aqueous mixture of different ethanol mass fractions at 293.2-318.2 K. In addition, the effects of agitation rate, pH value and Na⁺ concentration on the width of metastable zone were explored respectively. It was found that the solubility data might be described well by the model of λh equation; furthermore the mixing enthalpy and the crystallization enthalpy of uridine-5′-monophosphate disodium salt in mixture were determined. Similar to the solubility, the super-solubility increased with the increase of temperature and decreased with the increase of ethanol mass fraction. Under the same experimental conditions, increase of pH value, Na⁺ concentration or decrease of agitation rate might broaden the width of metastable zone.