Mar 29, 2011 · HPLC grade dichloromethane 1136 | Anal. Methods, 2011, 3, 1136â 1142 (Fisher Scientiï¬ c, Loughborough, UK) was used as the solvent for the test mixture. Certiï¬ ed amber and clear vials both screw and crimp tops were obtained from Speck and Burke Analytical (Alva, UK).