ICS-900 Operator’s Manual
118 Doc. 065215-02 9/09
1. Eluent Delivery
• Eluent, a liquid that helps to separate the sample ions, carries the
sample through the ion chromatography system. The ICS-900 is an
isocratic delivery system. This means that the eluent composition and
concentration remain constant throughout the run.
• Liquid sample is injected into the eluent stream either manually or
automatically (if an automated sampler is installed).
• The pump forces the eluent and sample through a separator column (a
chemically-inert tube packed with a polymeric resin).
2. Separation
• As the eluent and sample are pumped through the separator column,
the sample ions are separated. In the ICS-900, the mode of separation
is called ion exchange and it is based on the premise that different
sample ions migrate through the IC column at different rates,
depending upon their interactions with the ion exchange sites.
3. Detection
• After the eluent and sample ions leave the column, they flow through
a suppressor that selectively enhances detection of the sample ions
while suppressing the conductivity of the eluent.
• A conductivity cell monitors and measures the electrical conductance
of the sample ions as they emerge from the suppressor and produces a
signal based on a chemical or physical property of the analyte.
4. Data Analysis
• The conductivity cell transmits the signal to a PC running
chromatography software.
• The chromatography software analyzes the data by comparing the
sample peaks in a chromatogram to those produced from a standard
solution. The software identifies the ions based on retention time, and
quantifies each analyte by integrating the peak area or peak height.
The results are displayed as a chromatogram, with the concentrations
of ionic analytes automatically determined and tabulated.
NOTE For a glossary of chromatography terms, see
Appendix F
.
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