Yogurt: Sugar added (NH2P-50)

When analyzing saccharides in food, it is necessary to remove the substances besides saccharides before analysis. This procedure is called as sample pre-treatment. Here, the analysis result of saccharides in food using Asahipak NH2P-50 4E is shown together with the sample pre-treatment procedure.

(Sample pretreatment)
1) Take 5g of sugar added yogurt in a beaker, add 30mL of pure water and neutralize with 10%(w/v) NaOH.
2) Apply ultrasonic vibration for 30 minutes and make 50 mL solution.
3) Filtrate with No.5B paper filter and then with 0.45 micron membrane filter.

The comparison of NH2P-50 column and silica-based amino column for the analysis of yogurt(sugar added) is as follows:
1)The peaks of fructose and galactose cannot be detected using silica-based amino column.
2)In case of NH2P-50 column, the peak of lactose is lager compared with the case of silica-based amino column. This result shows the fact that most of lactose is adsorbed by silica-based amino column. Since the adsorption of lactose by NH2P-50 column is not so much, the detection limit of NH2P-50 column is lower than that of silica-based amino column.


Sample : Yogurt, 20micro-L
1. Fructose
2. Galactose
3. Glucose
4. Sucrose
5. Lactose

Columns      : Shodex Asahipak NH2P-50 4E, Amino column from other manufacturer (4.6mmID*250mm each)
Eluent       : CH3CN/H2O=75/25
Flow rate    : 0.6mL/min (NH2P-50), 1.0mL/min (Amino column from other manufacturer)
Detector     : Shodex RI
Column temp. : 25deg-C