Make sure the resin stays wet, either by flushing the column with water or eluant or by capping the bottom. A layer of sand is added to the top of the resin to keep in in place. Charging a Column and Testing the Effluent Add eluant to the top of the column slowly and carefully, so as not to disturb the resin bed. You can pour solution slowly down the side of the column opening or add solution dropwise, with a plastic dropper. Test the pH with indicator paper by taking a drop of effluent to piece of paper on a watch glass.
Acidic effluent can mean that cations are displacing protons on the ion exchange resin.
To test for the presence of sulfate, bring a drop of effluent to a clean watch glass. Look closely for a cloudy precipitate of BaSO 4 . Measure the height of the blue band and the total column height. When 5 mL of 0.015 M CuSO 4 solution is added to a column, a blue band measuring 1.0 cm forms. When the heights are measured, you estimate the values to the nearest 0.1 cm.