Modular anion system with chemical suppression and
dialysis
Automated sample preparation is increasingly becoming
an integral part of a high-performance IC system. With
the introduction of the patented dialysis method Metrohm
has placed a new milestone on the way towards this goal.
The determination of anions and cations in fruit juice,
milk, soil eluates or boring oil emulsions can be carried
out quickly and without any problems with the Metrohm "MIC-7
Advanced" dialysis system and without damaging the
separating column.
Dialysis is neither filtration, nor extraction, nor
digestion. In dialysis the ions pass from the sample
solution into the acceptor solution by diffusion through
a dialysis membrane. After only a short time a concentration
equilibrium becomes established in the sample solution
and the acceptor solution. The number of ions in the
sample solution is not reduced as they are constantly
being resupplied. While the ions can pass through the
membrane almost unhindered, larger particles - the matrix
- are simple transported past the dialysis membrane.
This reduces matrix effects to the absolute minimum.
The Metrohm dialysis method works according to the patented
stopped-flow principle: about 10 mL sample is passed
along the dialysis membrane by the peristaltic pump built
into the 838
Advanced IC Dialysis Sample Processor (2.838.0110)
while the acceptor solution remains at rest. The acceptor
solution is then transferred
to the sample loop of the 820
IC Separation Center and the sample is analyzed in
the normal manner.
High reproducibility, long membrane life, dialysis rates >98%
and very low detection levels for anions and cations
make the Metrohm Advanced IC Dialysis System into a powerful
tool for overcoming difficult application problems.
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