Observed adducts on positive mode direct analysis in real time mass spectrometry - Proton/ammonium adduct selectivities of 600-sample in-house chemical library.

In this study, direct analysis in real time adduct selectivities of a 558 in-house high-resolution mass spectrometry sample library was evaluated. The protonated molecular ion ([M + H]) was detected in 462 samples. The ammonium adduct ion ([M + NH]) was also detected in 262 samples.

Prediction of adducts on positive mode electrospray ionization mass spectrometry: proton/sodium selectivity in methanol solutions.

We used positive mode electrospray ionization (ESI) mass spectrometry to examine 540 in-house high-resolution mass spectrometry (HRMS) samples that formed an adducted positive ion. Of the 540 samples, the sodium adduct ([M+Na]⁺) was detected in 480 samples, and the protonated molecule ([M+H]⁺) was detected in 92 samples; both [M+Na]⁺ and [M+H]⁺ were detected in 32 samples. No other adduct ions were predominant.

Comparison of the applicability of mass spectrometer ion sources using a polarity- molecular weight scattergram with a 600 sample in-house chemical library.

To provide a practical guideline for the selection of a mass spectrometer ion source, we compared the applicability of three types of ion source: direct analysis in real time (DART), electrospray ionization (ESI) and fast atom bombardment (FAB), using an in-house high-resolution mass spectrometry sample library consisting of approximately 600 compounds. The great majority of the compounds (92%), whose molecular weights (MWs) were broadly distributed between 150 and 1000, were detected using all the ion sources. Nevertheless, some compounds were not detected using specific ion sources.