HILIC

HILIC on polar stationary phases employs organic-rich mobile phases, usually containing 5–40% water or a buffer (usually volatile ammonium formate or ammonium acetate if used in combination
with MS or charged aerosol detection, CAD).
Other solvents than MeCN often provide in-sufficient sample retention and broad or non-symmetrical peak shapes.
Can use tetrahydrofuran. THF, 1-propanol, 1,4-dioxane,  and  N, N -dimethylformamide
These solvents are more viscous than ACN, which renders the separation efficiency.
Toluen is a common compound for t0 determination by UV-detector at wave length of 254 nm