Can I use the dual ESI for dopant addition?

Question

Hi all,

I have a 6520 LC/MS QTOF with Masshunter B.06.00. It has a dual ESI source, and we'd like to use the second needle to introduce sodium hydroxide to enhance deprotonated ion formation. Currently we are injecting the NaOH with a T into the line for inline chemistry. We are curious about the feasibility of trying gas phase chemistry instead because then we wouldn't make our primary ESI needle dirty with NaOH.

Can do?

Thanks. - Kelsey

testuser · Accepted Answer

Hi Kelsey, Yes, it will work in principle, but it will take some finessing. The efficiency of ionization and sensitivity may be compromised. This is because the second needle has a fixed rate of fluid introduction; I think the default rate may be 5 ul/min, and you can't really play around with that. But you can still adjust the flow rate coming off the primary needle. You don't need to do anything special in software. Enjoy! - Jose