KINETIC-ANALYSIS OF FORMATION AND DEGRADATION OF 1-MORPHOLINO-1-DEOXY-D-FRUCTOSE

The kinetics of the reaction of glucose with morpholine to produce mor pholino-1-deoxy-D-fructose (Amadori product) were studied under experi mental conditions that minimize side reactions and maximize Amadori pr oduct formation (pH 3.0, T = 100 degrees C, 90% methanol-water, 6 h). Glucose (0.1 M) was reacted in sealed vials with a series of morpholin e solutions (0.1-0.3 M), and similarly morpholine (0.1 M) was reacted with different concentrations of glucose (0.05-0.2 M). At specific tim e intervals, the samples were analyzed for the presence of reactants a nd Amadori product by a multidetector HPLC system (diode array and pul sed amperometric detector). Under the experimental conditions, morphol ine alone (in the presence of glucose equivalent of sorbitol) and gluc ose alone (in the presence of morpholine equivalent of triethylamine) did not degrade. Similarly, the degradation of Amadori product (0.02 M ) was also studied in the presence of excess glucose. The data obtaine d were used to study the kinetics of color and fluorescence formation and to calculate the rate constants for the formation and degradation of Amadori product using two approaches: one involving the use of inte grated rate laws and graphical methods and the second involving simult aneous numerical solutions of the differential rate equations followed by optimization, such that the proposed model fits best the data. Bot h approaches gave comparable results. The second-order rate constant f or the formation of morpholine Amadori compound was calculated to be 1 .87 M(-1) h(-1).