Grades and purity
HPLC grade
Definition
Solvent of very high purity with low UV absorbance and low residue, made for high performance liquid chromatography.
HPLC grade solvents such as acetonitrile, methanol and water are filtered and purified so they do not create noise or ghost peaks in chromatography. Specifications usually cover UV cutoff, residue on evaporation, water content and gradient suitability.
For mass spectrometry, use LC-MS grade, which has tighter limits on metal ions and other ions.