Chromatography Forum

Hi

Has anyone had experience in CAD and troubleshooting baselines. I am currently running a gradient of methanol to IPA both at 5mM ammonium formate (100/0-0/100 over ~30 min) but it seems once the gradient reaches 50/50 the baseline gets very spikey and disturbed for a couple of minutes and then settles down again. Any ideas what this may be from?

Also does anyone know when the nebulizer temperature requires adjustment? Currently it is set to 25oC throughout all methods.

Cheers

Is there a possiblity the buffer is precipitating out? The CAD is sensitive to particles.

50/50 is the maximum viscosity composition for meoh/water and perhaps this affects the nebulization behavior. Perhaps you could optimize the nebulizer conditions while pumping this composition isocratically

Hi

Thanks for your thoughts, I increased the nebulizer temperature to 35degrees and that seemed to help with the spiking. There is still random spiking occuring throughout the run mainly at the methanol end of the gradient.

You are right LC_labrat the CAD is very sensitive to particles and it can take a few bottles of solvent before we find a solvent good enough to run.

I was wondering what brand and grade of solvent other people are using for CAD work?

Cheers