while operating this ISOCRATIC HPLC, ELICO MAKE, with C-18 Column,
1ml/min, Manual injection
i get only hill like peaks and nothing else.
i have also tried various mobile phases but at the end i receive the same result.
can anyone help in this??
With this little information, to me it seems that the pump is not well purged and then the pressure is not constant that is why you have these peaks (not chromatographic peaks). Can you confirm that the pressure in your pump is constant?
Can you give more informations about the problem. It seems that the signal is too low.
That is a lot of variation almost 700 PSI. You need to troubleshoot your instrument since this variation is giving you the instability in the signal. To me it seems that something is not well purger, look in the mobile phase lines for bubbles and make sure all is well connected, and you do not have leaks.
An intense in pressure is a sign of a clog somewhere. Check if the solvants are well filtered and of HPLC quality.
It looks like one of your pumps isn't delivering properly There is a repeating pattern. This suggests a pump issue. I note that the frequency of this pattern decreases during the run- are you running a gradient? The back pressure should not change much except for gradients, where a smooth change is expected from changes in solvent viscosity.
Elhadji Mamadou Moctar Niang While a clog increases pressure, it is almost never rhythmic- the back pressure increases until the pressure limit is reached.
One more thing- what solvents and UV detection are you using? It appears that the detection wavelength overlaps the solvent absorbance. This is OK for isocratic although the dynamic range of the detection is decreased. For gradients, you'll get a drifting baseline.
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