by 
sball » Wed Jul 04, 2007 3:14 pm
													
																																																									
					 
					
						Hi Josebenjamin, 
Here is some information about cleaning of HyperREZ XP ligand exchange columns for you, hopefully it will be of use. This information is taken from a user guide for such a column.
Initially, the column should be flushed with HPLC grade water in the reverse direction for at least 12 hours at the appropriate operating temperature (in your case, for the Ag+ and Ca++ columns this is in the region of 80-90 °C). This may remove particulate contamination at the inlet of the column. 
For strongly retained contaminants, the addition of a small amount of organic modifier to the mobile phase can be beneficial (<30% v/v acetonitrile, <5% v/v methanol or other alcohol). 
These types of HPLC column can become contaminated with other counter-ions (i.e. the Ag+ and Ca++ ions that are usually associated with the stationary phase become displaced by another positively charged ion), and this is a more serious problem! Extensive flushing of the column with a 0.1M solution of the appropriate nitrate salt (or 0.05M sulfuric acid in the case of Hydrogen counter-ion columns) can help to regenerate the resin in this case. 
In terms of caring for these columns, users need to ensure that they are not run at too high a pressure and to gradually increase flow rate to the desired level once its operating temperature has been reached. This will avoid accidental compression of the packing material, and therefore a void inside the column (usually accompanied by a substantial increase in back pressure). If the columns are to be stored for extended periods of time, it is advisable that they are flushed with 100% HPLC grade water beforehand. 
Finally, a good way of testing the performance of the column is to inject a 10mg/ml solution of Glucose. 
Best Regards, 
Steve.