baseline negative

[RAMESH JANGA]

Dear all
Please give me suggestion for baseline is observing nagative during gradient by using following conditions

Column: Symmetry C8 250x4.6mm 5u
Wavelength:230nm
Flow:1.0ml/min
Solvent-A: 0.1% TFA in water
Solvent-B: Methanol: Acetonitrile(80:20)
Gradient
time/%B: 0.01/35,3.0/35,30/80, 40/90,45/35,50/35.


regards
ramesh

[Csaba]

Hi,
TFA in mobile phase A absorbs light at 230 nm.
Either accept a sloping baseline or add some TFA to your mobile phase B.

[mohan_2008]

on the contrary,

I think the MeOH in B solvent is absorbing.

[HW Mueller]

It seems obvious that the absorption of TFA is the predominant factor here.