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Sugar Determination in Dairy Products
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Abstract
In food chemistry the determination of sugars in dairy
products is of the utmost importance. When carrying out
direct ion chromatographic determinations the precipitation
of protein constituents on the column is a recurring
problem. Instead of demanding precipitation procedures
the dialysis technique can be used to separate the interfering
protein matrix. The use of dialysis as an inline sample
preparation step results in a rapid automated analysis
system. The sugar constituents are determined by means
of pulsed amperometric detection.
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The problem |
Sugar analysis plays an important role
in food control. In many cases, as the low-molecular sugar
constituents are readily soluble, sample preparation is
straightforward and rapid. However, the analysis of protein-containing
samples can pose severe problems. Precipitation of the
proteins affects the column and ultimately destroys it.
This can be prevented if demanding precipitation procedures
(e.g. Carrez precipitation) are carried out before the
analysis. However, such sample preparation steps may lead
to co-precipitation, inclusion or even decomposition of
the sugars to be determined. |
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Solution outline |
Dialysis can solve the above problem.
The separation of the low-molecular sugars from the high-molecular
proteins is determined exclusively by the osmotic pressure
at the membrane. This means that, due to the concentration
difference existing across the cellulose membrane, the
sugars migrate from the sample stream into the acceptor
solution (e.g. ultrapure water) whereas the high-molecular
protein constituents stay on the sample side of the membrane.
This sample preparation step occurs inline and can therefore
be completely automated. The time needed is negligible
as the dialysis is performed during the recording of the
previous sample's chromatogram. The instrumental setup
is described on the MIC-8+Dialysis page. |
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Get more information |
> Methology
> Application
Examples
> Application
Notes & Bulletins for Food Industry
> Sample
preparation with MISP
> Product
information (MIC-8+Dialysis) |
You did not find a solution for your application?
Do not hesitate to contact
Metrohm!
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