High resolution and high throughput analytical methods for d-tagatose and process related impurities using capillary electrophoresis.

d-tagatose is a low calorie multifunctional rare ketohexose sugar with sweetness similar to that of sucrose and it has high potential benefits for food and pharmaceutical industries. It is found in traces in some fruits as a natural component. In view of its high demand as a substitute for sugar, mass production of d-tagatose through enzymatic conversion of Lactose to d-tagatose is adopted. The existing HPLC method has limitations with respect sensitivity and resolution in quantification and monitoring of d-tagatose in the presence of its process related impurities. In the present investigation a new robust, fast and green analytical technique has been developed based on capillary electrophoresis (CE) for the separation and quantification of d-tagatose in presence of other sugars: Lactose, d-glucose, d-galactose and d-talose. Optimum conditions are found to be: Back Ground Electrolyte (BGE): 36 mM of Na2HPO4 and 130 mM of NaOH; pH: 12.6; voltage: +18 kV for high resolution and -18 kV for high throughput methods with direct UV-Detector at 265 nm. At these optimum conditions, good separation between the sugars is achieved in less than 20 min for high resolution and less than 4 min for high throughput methods. The developed methodology is validated as per ICHQ2R1 guide lines and successfully applied for monitoring d-tagatose during the enzymatic conversion of Lactose/d-galactose to d-tagatose and also to determine the unknown amounts of d-tagatose in crystallized samples and further, it is used in identifying the d-tagatose in fruits.

A sensitive and high throughput method for the analysis of d-psicose by capillary electrophoresis.

d-Psicose/allulose is a rare sugar and it has high potential benefits for pharmaceutical and food industry. The existed analytical methods have its own limitations to quantify fructose and d-psicose mixtures. Hence there is a need for the development of an effective, efficient and sensitive analytical method for quantification of d-psicose in presence of other sugars. Quantification of sugars by capillary electrophoresis (CE) have been previously reported. However, the list does not include d-psicose. In this study, d-psicose is successfully quantified for the first time in the presence of d-fructose and glucose with a good resolution. Standard curves for all the sugars are established in a concentration range of 0.1 mM (0.0018% w/v) to 3.0 mM (0.0540% w/v) with a coefficient of determination of >0.99. The scope of this method can be extended to quantify d-psicose and their processed impurities in food products with minor modifications in sample preparation.