By Anonymous on Tuesday, December 24, 2002 - 12:34 am:
I am currently trying to understend the reason causes to the main peak splitting. I am using CN(NP),5µ, 200x4.6mm column, the mobile phase is Phos.buffer:ACN (80:20),the Buffer pH is 5.4, Pka of the substance is 7.4, The sample solution pH is 3.3-4.0. We think is due to the high concentration(0.1mg/mL)which causes to column overloading, but when the coulmn "is rested" few days ,no spliting peak is observed. Any suggestions for reasons of peak splitting?How can we solve our problem?.
By Anonymous on Tuesday, December 24, 2002 - 12:56 am:
Probably the problem is in the column condition/equilibration. A concentration of 0.1 mg/ml is not to much to overload the column. In CN(NP) column (NP) means Normal Phase design of the column. Try CN(RP).
By Anonymous on Tuesday, December 24, 2002 - 03:10 am:
cyno columns are not so stable as compaired to c18 or so. You can use zorbax SB CN and regenerate the column u r using.
By Anonymous on Tuesday, December 24, 2002 - 06:55 am:
On a hunch, how many ul are you injecting? Try injecting half and see if situation is better, worse, or same....
By Anonymous on Tuesday, December 24, 2002 - 02:49 pm:
You do not have a good buffer. Either use a buffer closer to 7 (the pKa of phosphate), or adjust the pH of the sample to the same as the mobile phase.
By Anonymous on Sunday, December 29, 2002 - 07:32 am:
Well you not mentioned whether initial injection gives peak spliting or after few injections.
In case after few injection peak gets spliting than used gard column to prevent analytical column from any contaminant get deposited on column due to which peak may gets split.