Chromic acid is not recommended as the residual chromium often adversely affect NMR experiments. If chromic acid is used ... For samples that are not dissolved by acid (e.g., some polymers), a solvent ...

While 2D NMR is frequently employed to enhance ... hindering the analysis of signals from residual organic solvents like ethyl acetate, acetonitrile, etc., and compounds similar to Ibuprofen ...