ICS-3000 Ion Chromatography System
120 Doc. 065031-04 1/08
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 the
OnGuard cartridge for instructions. The guide is located on the Dionex
Reference Library CD-ROM (P/N 053891).
4.3.3 Diluting Samples
Because the concentrations of ionic species in different samples can vary
widely from sample to sample, no single dilution factor can be
recommended for all samples of one type. In some cases (for example,
many water samples), concentrations are so low that dilution is not
necessary.
Use eluent or ASTM Type I (18 megohm-cm) filtered and deionized
water to dilute the sample. When using carbonate eluents, diluting with
eluent minimizes the effect of the water dip at the beginning of the
chromatogram. If you dilute the sample with eluent, also use eluent from
the same lot to prepare the calibration standards. This is most important
for fluoride and chloride, which elute near the water dip.
To improve the accuracy of early eluting peak determinations, such as
fluoride, at concentrations below 50 ppb, dilute samples in eluent or spike
the samples with concentrated eluent to minimize the water dip. For
example, spike a 100 mL sample with 1.0 mL of a 100 X eluent
concentrate.
4.3.4 Fill the Autosampler Vials and Load the Sample Tray
1. Follow the instructions in the autosampler manual to fill the vials and
load them into the sample tray or cassette. The autosampler manuals
are included on the Dionex Reference Library CD-ROM
(P/N 053891).
2. Load the tray or cassette into the autosampler and close the
autosampler door.
Tips for Filling and Loading Vials
• For an AS, fill the vials no higher than the vial shoulder. Make sure
the needle vent is not immersed in liquid during sampling.
• For an AS40, fill the vials to the level marked on the vials.
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