Premium
Towards the electrospray ionization mass spectrometry ionization efficiency scale of organic compounds
Author(s) -
Leito Ivo,
Herodes Koit,
Huopolainen Merit,
Virro Kristina,
Künnapas Allan,
Kruve Anneli,
Tanner Risto
Publication year - 2008
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3371
Subject(s) - chemistry , electrospray ionization , direct electron ionization liquid chromatography–mass spectrometry interface , extractive electrospray ionization , mass spectrometry , desorption electrospray ionization , ionization , ambient ionization , chemical ionization , chromatography , environmental chemistry , sample preparation in mass spectrometry , analytical chemistry (journal) , organic chemistry , ion
An approach that allows setting up under predefined ionization conditions a rugged self‐consistent quantitative experimental scale of electrospray ionization (ESI) efficiencies of organic compounds is presented. By ESI ionization efficiency (IE) we mean the efficiency of generating gas‐phase ions from analyte molecules or ions in the ESI source. The approach is based on measurement of relative ionization efficiency (RIE) of two compounds (B 1 and B 2 ) by infusing a solution containing both compounds at known concentrations ( C 1 and C 2 ) and measuring the mass‐spectrometric responses of the protonated forms of the compounds ( R 1 and R 2 ). The RIE of B 1 and B 2 is expressed as log RIE (B 1 , B 2 ) = log[( R 1 · C 2 )/( C 1 · R 2 )]. The relative way of measurement leads to cancellation of many of the factors affecting IE (ESI source design, voltages in the source and ion transport system, solvent composition, flow rates and temperatures of the nebulizing and drying gases). Using this approach an ESI IE scale containing ten compounds (esters and aromatic amines) and spanning over 4 log RIE units has been compiled. The consistency of the scale (the consistency standard deviation of the scale is s = 0.16 log RIE units) was assured by making measurements using different concentration ratios (at least 6‐fold concentration ratio range) of the compounds and by making circular validation measurements (the log RIE of any two compounds was checked by measuring both against a third compound). Copyright © 2008 John Wiley & Sons, Ltd.