ICS-1000 Ion Chromatography System
3-12 Doc. 031879-01 3/03
3.9 Prepare Samples
NOTE Sample preparation can be performed while the system
is equilibrating.
3.9.1 Collecting and Storing Samples
Collect samples in high density polyethylene containers that have been
thoroughly cleaned with deionized (DI) water. Do not clean containers
with strong acids or detergents because these can leave traces of ions on
the container walls. The ions may interfere with the analysis.
If samples will not be analyzed on the day they are collected, filter them
through clean 0.45 µm filters immediately after collection; otherwise,
bacteria in the samples may cause the ionic concentrations to change over
time. Refrigerating the samples at 4
° C (39° F) will reduce, but not
eliminate, bacterial growth.
Analyze samples containing nitrite or sulfite as soon as possible. Nitrite
oxidizes to nitrate, and sulfite to sulfate, thus increasing the measured
concentrations of these ions in the sample. In general, samples that do not
contain nitrite or sulfite can be refrigerated for at least one week with no
significant changes in anion concentrations.
3.9.2 Pretreating Samples
Analyze rainwater, drinking water, and air particulate leach solutions
directly with no sample preparation (other than filtering and possibly
diluting).
Filter groundwater and wastewater samples through 0.45 µm filters
before injection, unless samples were filtered after collection.
Before injection, pretreat samples that may contain high concentrations of
interfering substances by putting them through Dionex OnGuard
®
cartridges. Refer to the Installation and Troubleshooting Guide for
OnGuard Cartridges (Document No. 032943) for instructions.
To Next Page
