Matrix reduction in pharmaceutical samples by Metrohm Inline 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 pharmaceutical intermediates, preparations as well as products from solutions through suspensions through emulsions can be carried out quickly and without any problems with the Metrohm "MIC-7 Advanced" dialysis system and without damaging the separating column.

In dialysis the ions pass from the sample solution into the acceptor solution by diffusion through a dialysis membrane. While the ions can pass through the membrane almost unhindered, larger particles - the matrix - are simply 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 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.