Procedure 2.6 Preparation of the Cation Exchange Column

Cation Exchange Experiments (Analyses should be done in Triplicate) 

Precisely weigh (to the nearest 0.1 mg) 0.15-0.25 g samples of your cobalt compound into a 100 ml beaker. 

Dissolve each sample in a minimum amount (—40-50 ml) of de-ionized water and record the volume used. Briefly sonicate the solution to dissolve the solid, if needed. (Note for some compounds somewhat more than 50 ml may be required.) To guard against the effects of substitution reactions, dissolve the samples just prior to each analysis and do not heat the solutions. 

Carefully pour the first sample on the column. Allow it to drain to the top of the resin bed, then flush it through with five or six 20 ml portions of de-ionized water and record the volume used. Collect the eluent (solution that comes off the column) in a 500 ml Erlenmeyer flask. 

Titrate the eluate with a standard 0.1000 M NaOH solution (provided) using methyl orange indicator. The endpoint of the titration is reached at the color change of the indicator this will take place within one drop of titrant. Record the volume of titrant added (to the nearest 0.05 ml) at the endpoint. 

---