SI-50 application and Shodex catalog

Record: 856

Category: Column Problem
Product: SI-90 4E
Sample:

Question
The mobile phase was made fresh and degassed. I removed my guard column and the pressure dropped down to just under 700psi, but the peaks are still eluting much later than anticipated. Is it possible that something is wrong with the column?

Answer
What was the pressure of the system before the guard column was removed? Approximately how many injections have been analyzed with the column? Have you observed any change in column back pressure? Another question is that when did you realize the shift in retention time? -Did it happen in gradual and consisting manner or did it happen after some event (e.g., change of eluent)?

Perhaps you may need to regenerate the column depending on the samples (hydrophilic/hydrophobic) that are injected onto the column. Please see page 4 of the attached operation manual for the regeneration procedures.

Our records show the column was purchased in Jan. 2013; please remember that HPLC columns are consumable products, so they do deteriorate over a time.

 
 
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