By Laura on Thursday, March 20, 2003 - 07:56 am:
When analysing folic acid using HPLC, the peak heights keep dropping even with consistent injection volumes by weight. The bulb in the detector has been changed so this isn't thought to be the problem. Any suggestions?
By Jan on Thursday, March 20, 2003 - 08:04 am:
What about peak area's ? Do they drop as well, or are the peaks just getting broader ?
By Tom M. on Thursday, March 20, 2003 - 10:33 am:
Does this happen with standard or just your sample? What is the column, MP, sample matrix, etc. Need a little more information to help you
By Laura on Friday, March 21, 2003 - 12:43 am:
They are still sharp peaks, but the heights and the areas keep dropping. It does happen with the standards and presumably with the samples as we don't know their values. The folic acid is extracted in a basic solution of methanol and water. The sample is then cleaned up on an anion exchange column. Quantification is then carried out by HPLC with post column derivitisation to produce an oxidised folic acid derivative which is detected by fluorescence.
By Uwe Neue on Friday, March 21, 2003 - 03:06 pm:
Did you consider that your post-column reaction might not be stable? The reagent? The reaction conditions, especially temperature? The flow rate of the reagent? Background that suppresses the fluorescence?