Background: In this study, the postcolumn addition approach was used to evaluate the impact of high pH modifiers on the sensitivity of 25 compounds by LC-MS/MS under positive ESI (ESI+).
Results: None of the compounds were significantly suppressed by the use of high pH modifiers. Most of them showed a signal enhancement by at least twofold compared with acidic modifiers. The sensitivity gained under high pH mobile phase was used to develop a bioassay for the quantification of candesartan. The use of high pH mobile phase allowed for fast sample preparation that would have been impossible under typical low pH chromatography.
Conclusion: We have shown that high pH modifiers are sufficient to induce a signal enhancement for the majority of compounds detected under LC-ESI+-MS/MS.