Chromatography Forum

We just purchased a Dionix IC for anions. It's lots more sensitive than the colorimetric method we currently use. We are getting a nitrate peak in all our blanks at our action limit! We run a lot of metals in drinking water so there is a lot of nitric acid used.
We have put no2/no3 test strips throughout the lab which come up positive.
Any ideas how to deal with this without moving the system?

Switch to RO polished water (or am I missing something)?

This may sound like telling the cobbler's children to get new shoes, but check your hoods and ventilation; you might be picking it up from the atmosphere.

An update on this problem. It seems that the contamination was coming from our DI water. We sanitized the unit and replaced membranes and got rid of the nitrate peak.

Thanks for the update. It's always nice to know the end result!