By madhusudhan reddy on Saturday, August 31, 2002 - 07:24 am:
We are using Shimdzu HPLC. We are facing nagative peak problem. In blak run also we are getting nagative peak. we are taking water and acetonitrile in the ratio of 50:50. the nagative peak is dominating the main product peak that means hight of the nagative peak is larger than produt, so please sugest for this particulr problem.
By Anonymous on Saturday, August 31, 2002 - 07:52 am:
What detector do you use? If RI, this may be normal. If UV, what wavelength?
By Anonymous on Tuesday, September 3, 2002 - 05:26 am:
Negative peaks in RI are very common. In most cases it is either the solvent peak or (more commonly) the result of the pressure spike from the injector. The solution, in your case, is to modify your chromatography so you peak of interest is retained longer, moving it farther away from the negative peak. Based on your 1:1 ACN/Water MP, this should not be too difficult.
By vestelshirley on Thursday, September 12, 2002 - 07:17 am:
Also, a mismatch between the ri of the carrier liquid and that of the sample might cause the problem.