By Anonymous on Wednesday, August 20, 2003 - 07:29 am:
What are some functional groups that can lead to the killing of C18 silica columns. In particular what causes the PPI 'zoles' to consume columns so quickly. This is assuming that the cause is not mobile phase pH, temperature, or inactives.
By Anonymous on Thursday, August 21, 2003 - 03:38 pm:
???
By Anonymous on Friday, August 22, 2003 - 12:46 pm:
Ummmm,
Not sure what PPI 'zoles' are.
By Anonymous on Monday, August 25, 2003 - 10:32 am:
Proton Pump Inhib. Omeprazole Pantoprazole ect.
By Anonymous on Monday, August 25, 2003 - 04:02 pm:
Compounds don't kill columns. Mobile phases or junk in the sample do. What is your mobile phase? What is you sample (pills, plasma???)?
By Anonymous on Monday, August 25, 2003 - 04:08 pm:
Compounds don't kill columns. Mobile phases or junk in the sample do. What is your mobile phase? What is you sample (pills, plasma???)?
By Anonymous on Tuesday, August 26, 2003 - 06:17 am:
mobile phase is pH 6.8 phosphate buffer/meoh gradient, temp is a 35, sample is only raw material in water/meoh/NH4OH 80/18/2
By Anonymous on Tuesday, August 26, 2003 - 03:23 pm:
You did not give the buffer concentration. If you inject an excess of ammonia you may kill the columns from this. Neutralize the sample and try again! At this moment, I bet that this is where the problem is.
By Anonymous on Wednesday, August 27, 2003 - 05:37 am:
We have experienced that injections of hydroxide can shorten the life span of a cC18-silica column, even if the mobile phase has a lower pH. If you can't switch to a polymeric reverse phase column, you should have a guard column, and expect to change it frequently