Apparatus consisting of the following: (A) Reservoir, 175ml, with standard taper (19/22) joint at bottom and a #27 stopper at top with 4mm Teflon® stopcock. (B) Flask, 20ml, with standard taper (19/22) joints at top and bottom and standard taper (7/15) on inner tube. (C) Column, 2mm Teflon® stopcock with coarse porosity fritted disc and a standard taper (19/22) outer joint at top, 19mm ID column 270mm long from top of (19/22) joint to stem of column. (D) Base, standard taper (19/22) outer joint. (E) Extension tube, for use with flask, standard taper (7/15).