You will want to have both your A and B solvents (aqueous and organic) in Teflon mobile phase reservoir bottles. The reason for using these bottles is that sodium present in borosilicate glass mobile phase reservoirs can lead to issues for anionic analytes in negative ion mode LCMS. These include phosphates and organic acids but can be others as well.

It is also advised that you consider using Reduced Surface Activity (RSA) glass vials for your samples to minimize sodium adducts, pH changes or basic compound adsorption.