Glass vacuum chromatographic apparatus with filter disc porosity 0 compound : a vacuum flask 250 ml rode 19/26 screwsocket a chomatographic column 19/26 screwsocket with sinter porosity 0 a dropping funnel with stopcock PTFE key 19/26 screwsocket 2 capsand seals 19/26 screwsocket borosilicate 3.3