Study On The Purification Technology Of Folic Acid

Folic acid is an important water-soluble vitamin,and it can promote cell devision and generation,effectively preventing all kinds of folic acid deficiency.Preparation of high purity of folic acid,not only can provide reference material for analysis and detection of folic acid but also provide reference to purify other thermally unstable and light instability substances.The crystallization conditions of folic acid were firstly studied with the 95.2% folic acid as the raw material.And the influence of various factors on the crystallization process of folic acid was investigated by using single factor experimental design and orthogonal experimental design.The best crystallization conditions were as follows: crystallization temperature 85 ?,acidified solution volume 10 mL,the mass fraction of hydrochloric acid 10%,initial concentration 2.33 mg/mL,hydrochloric acid dropping speed 1.0 mL/min,stirring speed 250 rpm and pH 0.6.Under these conditions,the product purity could be 98.2%.The product was qualitative analyzed by the liquid chromatography-mass spectrometry(LC-MS),nuclear magnetic resonance(NMR)and infrared spectroscopy(IR),respectively.LC-MS also was used to analyze the impurities and the main reducing impurity was identified as N-(4-aminobenzoyl)-L-glutamic acid.In order to obtain higher purity of folic acid,the preparative high-performance liquid chromatography method was studied and the best preparation conditions were obtained.A gradient mobile phase composing of acetonitrile and water was applied,and the flow rate was16 mL/min,detective wavelength was set at 254 nm,the injection volume was 2.0 mL and freeze-drying was used as drying method.Under these conditions,the purity of folic acid could reach 99.4%.The product was further qualitative analyzed by LC-MS,NMR and IR,respectively.The content of the ash impurities was 0.0293% determined by thermal gravimetric analysis(TGA),the inorganic elements impurities was 0.0637% by inductively coupled plasma emission spectrometry(ICP-OES),and the volatile impurities was determined by gas chromatography.The results also showed that the product does not contain volatile impurities.The short-term stability of folic acid was compared under different storage conditions;the results indicated that folic acid should be stored at 4 ?.