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 pre-treatment procedure for yogurt)
1) Put 5g of yogurt in a beaker and add 30mL of 50%(V/V) ethanol.
2) Extract the substances from yogurt using an ultrasonic vibrator for 30 minutes.
3) Put the paste and ethanol in a 50mL messflask and add 50%(V/V) ethanol to make
up a 50mL solution.
4) Filtrate the solution with a paper filter(No.5B) to remove the paste.
5) Take a part of filtrated solution and add the same volume of acetonitrile.
6) Pass through a 0.45micron membrane filter before injecting into HPLC.
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 nother manufacturer)
Detector : Shodex RI
Column temp. : 25deg-C
