Development Of Crystallization Technic For 5'-guanosine Monophosphate Disodium

5'-Guanosine Monophosphate Disodium (GMP) is a kind of nucleotide, which is used asfood freshener. Because of visible qualitative shortages in purity, crystal size and morphology,domestic GMP products are at a disadvantage in international market competition. The aim ofthis paper is to systematically investigate crystallization technics of GMP for improvingqualityof GMP.Solubilities of GMP in water-ethanol solvent mixtures were determined by gravimetricmethod. Meanwhile, super-solubilities of GMP in the mixtures were determined byturbidimetric method. Experimental data were successfully correlated by Apelblat equationwith correlation coefficient, and effect of pH, solvent ratios and temperatures on solubility,super-solubilityand metastable zone were discussed in detail.Technological studies on anti-solvent crystallization of three different GMP rawmaterials were conducted by single factor method, and effects of different factors oncrystallization were studied. Properties of GMP samples were analyzed accordinging to theGMP standard of food additive (QB/T 2846-2007). Crystal morphology was also recordedand analyzed by microscope.Based on the experimental results, feasible crystallizationconditions were chosen for different raw materials.Finally, influencing factors of polymorph transformation and crystal yield duringcrystallization were investigated by using on-line Focused Beam Reflectance Measurement(FBRM) and microscope.This paper will be useful for quality control of anti-solvent crystallization of GMP.