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Supressing Cl ions from evaporating in HF

Posted: Fri May 15, 2009 2:07 am
by joelyue
Hi,

i am trying to quantify trace Cl in HF acid using an Ion Chromatography system. However when doing a recovery, i find that all the Cl ions is lost when i evaporated the HF acid.

Does anyone know of any chemical which i can add to prevent the loss of Cl ions while still eliminating the F ions which upset the accuracy of the chromatogram?

Posted: Fri May 15, 2009 8:35 am
by HW Mueller
To where do you evaporate HF (are you really talking about hydrofluoric acid?).
These old ion assays, which are usually quite a bother for general chemistry students, might work. Don´t remember if a reaction of F- with AgNO3 was mentioned.

Posted: Mon May 18, 2009 12:29 am
by joelyue
Yes when i mentioned HF i do mean Hydroflouric Acid.

I usually evaporate the HF in a fume chamber. The HF fumes are then sucked into the exhaust system and scrubbed by a scrubber before releasing into the atmosphere.

Posted: Mon May 18, 2009 9:28 am
by HW Mueller
Just wonder how the HF is scrubbed. Maybe you can use that technique to get at the Cl-?