ELSD use nitrogen or compressed air

[vliu]

I am trying to find out more user information in regards to ELSD also trouble shooting I realised this has been asked awhile ago but no specific information on troubleshooting, please advise if you know a good site or two.

Also, could somesome advise me if using compressed air rather than nitrogen is possible with ELSD? I tried running with compressed air once, a much higher response was observed (3 times more) but all the peaks of interest were split. I am unsure if it's due to the higher pressure i was using (I increased the pressure to get a flat baseline) or it's due to compressed air itself.

[Vlad Orlovsky]

We are using compressed air for the last 5 years without any problem. (3 bar)

[ihenderson]

ELSD manufactures recommend the use of nitrogen or other inert gas as the nebulization gas. ELSDs use elevated temperatures to evaporate the HPLC mobile phase. Many mobile phases contain volatile organic solvents. Using a gas that will not support combustion is recommended as a safety measure.

The increase in response you observed is most likely a result of the increased gas flow. You can try to reproduce the result by increasing the pressure of the nitrogen to similar levels.

Here are two links to article from the LCGC archive that could help you with your troubleshooting questions.

http://chromatographyonline.findpharma. ... rticle.pdf

http://chromatographyonline.findpharma. ... rticle.pdf

[vliu]

Thanks for the replies.

This pressure is similar to what's in the method for Nitrogen, I guess compressed air whould be compatible with the method.

ihenderson:
Thanks for the links, they are very useful!!