Suppressed Ion Chromatography

As ion chromatography methods, two are well known: the suppressed method and the non-suppressed method. In the suppressed method, after the eluent has passed through the analytical column, ionic substances of which polarities are opposite of ionic substances in the sample are ridded by use of a special device(suppressor). By this method, the electro conductivity in the eluent can be largely decreased and highly sensitive analysis of anions is possible.
Shodex is offering several kinds of analytical column for the use of anion analysis by supressed method. It is highly recommended to use a line filter to obtain a stable beseline and a guard column to a have long service life of the main column.

Merit of suppressed method.
1. Background conductivity is low.
(anion analysis: about 20 micro-S/cmFS)
2. Sensitivity is high. Detection sensitivity is several ppb and minimum sample concentration is about tens ppb.
3. Free from temperature fluctuation and stable analysis is possible.

Demerit of suppressed method.
The use of a suppressor is essential and the system is rather expensive.