Where are protons in ESI+ formed in LC-MS/MS?

11 March 2020 1 3K Report

Can anyone help me with peer reviewed papers that explain whether or not ions are formed in the ESI source? Is this what they call 'right-way-round' principle?

Then how come that some for some analytes the eluent pH does not affect ionization efficiency much? Can this be explained by the 'wrong-way-round' principle?

Im having a hard time understanding these two principles because they both contradict each other as they explain different theories for the ionization. Is one of the two an exception rule?

Furthermore, how can one predict what eluent pH you should choose as a starting point? Or is there no other way than trial and error?

Asal Asali

Thank you @noelwdavies, but as far as I know, transfer of charge from the the tip is the mechanism of corona discharge which happens in APCI. From, for example H3O+ formed in ESI, its known that Corona discharge also takes place in ESI, however only to a certain degree. It shouldn't be the main mechanism of ion formation, right?

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