Online Concentration Monitoring Method And Solubility Measurement Of L-arginine-?-ketoglutaric Acid Based On Raman Spectroscopy

L-Arginine-?-Ketoglutarate(AAKG)is one kind of health care products of amino acid series that has high added-value with increasing sales in global market,the dissociation of AAKG in aqueous solution provides donors of L-Arginine or?-Ketoglutaric Acid.The manufacture of AAKG involves the reaction and crystallization of L-Arginine and?-Ketoglutaric Acid,thus online monitoring of concentration in the crystallization process of AAKG product is important in the quality control of the final products.In this paper,AAKG were prepared through reaction crystallization.The Raman characteristics of Model compounds-Ethanol-Water system were studied and the influences of temperature,pH and particle concentration were considered.Then,the external standard method was introduced to analyze the concentration of pure components in ethanol-free solutions.The concetration of multiple components in model compounds solution and single component in ethanol-water mixtures were analyzed through Partial Least Squares Regression(PLSR).The mean error of models'prediction outcomes were within 7%to the actual concentration.The solubility of each component in Model compounds-Ethanol-Water in the temperature range of 5~oC-45~oC and ethanol's mass fraction range of 0-0.8 were measured through the regression models obtained.Apelblat and Jouyban-Acree model were introduced to correlate the solubility data measured under different temperatures and solvent-ratios'mole fractions respectively,which fitted well with the experimental data.The solubility data were also verified by the data obtained through the weighing method,with only an average relative deviation within 6%.The Raman characteristics of Model compounds in Ethanol-Water system and the concentration of each component in Model compounds-Ethanol-Water system could be measured through the PLSR models of online monitoring of concentration established in this paper.The solubility data of AAKG could provide references for further studies of amino acid compound salts crystallization.