The links posted are certainly somewhat useful, but I have a few objections:
- Modifiers: a lot are listed there, but usually you only need a few of these.
Starting points are:
formic acid (0.1%) for positive mode and
acetic acid (0.05%) for negative mode.
Despite what is written in the blog post, basic mobile phases are not the best choice for negative mode. Standard C18-columns won't tolerate pH>8, and acetic acid works better than e.g. carbonate in many cases.
If you want ammonium adducts or want to suppress sodium adducts, add to or replace acid with ammonium formate / acetate (5 mM).
With these four modifiers you can conduct >90% of your analyses.
In some cases it may be helpful to use ammonium fluoride as modifier, as it can strongly enhance response, especially in negative mode. Use very low concentrations (0.1 mM).
-Adducts:
you don't want sodium adducts if your doing MS/MS, since they usually give no useable fragmentation. You don't want sodium in your system at all, since you will be getting sodium adducts when you don't want them. Stay away from sodium.
In negative mode the most common species you get is [M-H]-, but there can be a lot of adducts also, like formate, acetate, chloride,...
A list of common adduct ions can be found in J. Am. Soc. Mass Spectrom., 10 (1999) 1174.
https://www.sciencedirect.com/science/a ... 0599000902(Open Access)
Look for applications on the websites of the instrument and column manufacturers, often they have good recommendations.