Method Research On The Determination Of The Betalanins By High Performance Liquid Chromatography

Betalains are water-soluble nitrogen-containing pigments, which include the red-violet betacyanins and the yellow betaxanthins. Betalains are located in different parts of plants, in roots (Beta vulgaros), fruits (Phytolaccaceae) and flowers (Celosia,Nyctaginaceae). As food additives, betalains have been shown to be effective colorants of foods with compatible chemical, physical properties and antioixidant activities. Nowadays betalains has already been used in various kinds of food. But compared with foreign, the determination method of the betalains has a long way to go. So our country sets up and carries on the research specially.In this study, we used the HPLC to determinate betalains and developed the analysis method for betalains in the food. We selected the primary factors to assay determine effictiveness , such as chromatrgraphy column, mobile phase, flow rate etc.. The method was investigated in the methodological aspect through measuring the precision, recovery and stability of the method.The optimum chromatographic conditions were as follows:Shim-pack vp-ODS column (4.6mm i.d.×150mm,5μm) was used and mobile phase was MeOH:H2O-HAc(20:80) with flow rate of 0.8ml/min. The eluate was monitored atλmax=535nm . The linearity was obtained over the range of 0.0641～3.206mg/ml ( r=0.9999). The average recovery of sample was in the range of 97.58-102.1%, with relative standard deviation of 0.82%.In our work, the general principel of evalution and express of uncertainty of measurement results were introduced. The influence factors of measurement uncertainty of HPLC method were discussed, and more complete expression of measurement results is giver so that the method is more systematize and reliable.Most reports have described similar analysis methods by HPLC for betalains in the food , but these methods using gradient elution usually complicated and not to suit for requirement of the daily work. Some helpful suggestions have been made to the analysis of betalains. This work we selected ingradient elution system and methanol with low toxicity take the place of acetonitrile. The method was proved to be a simple, rapid and reliable way to determine the betalains concentration and has useful and referable value.