ESI or APCI

[jan]

What ionization method will be tried out first when one wants to do LC/MS analysis? Will it based on molecule polarity? Thanks.

[Basil]

Hi Jan,

I hardly strongly recomend you to see what's on structure: If there is a N in the structure and it's not to big (high molecular weight) I would begin with ESI in positive mode.

But it also depend in the HPLC mobil phase that you are using because some compounds could produce a bad spray with ESI........

More information will be usefull to help you.

Bye....

[Kostas Petritis]

Hi Jan,

I started by writing a long reply of all the factors that you need to consider but that is not what you asked. So...

Personally I start almost always with ESI except if I see that the molecule seems quite hydrophobic and without any chargable functional groups. If you have a molecule which response is the same with both ionisation techniques then I would go with APCI as it has been proven that you have less ion suppression from matrix interferences...

Kostas

[Basil]

Ops a big mistake !!

I hardly recomend you to see what's on structure

It should said: I strongly recomend you to study the structure to decide the kind of ionization that you are going to use.....

I agree with Kostas reply....

[tom jupille]

To Basil: the new Forum software allows you to edit or delete your own posts (to correct for typos!). Look for buttons in the upper right of the message box.