Chromatography Forum

hi
may i know how to detect leaching from HPLC system ( from SS tubes or other parts of system..), also what all promots/causes such leaching??

thanks a lot

Leaching in liquid chromatography mainly refers to the stationary phase one. Leaching will depend on the type and quality of the stationary phase as well as the chromatographic conditions. Many silica based amino columns are very prompted to leaching, some polar endcapped reversed phase may leach or even regular silica based C18 columns will start to leach if operated at extreme pH and/or temperature conditions. Your ability to detect leaching will depend on what is leached and what type of detector are you using. In general mass spectrometry can detect a lot of types of leaching or evaporative light scattering detectors (if the leaching is quite bad) etc...

For other types of leaching, and assuming that you are using high quality HPLC grade/compatible components, I would say that you won't observe any leaching with the exception maybe of some types of ion chromatography...

hi Kostas Petritis
thanks a lot for ur reply....

well i am woundering is it possible for leaching from HPLC system (not the column) if i am injecting high pH buffer (my sample is in ammonium bicarbonate...) ??? does this buffer affect any of my injection port or other parts...
i am using agilent 1200 system with Uv detector...

No, you are safe, injection valves are pretty inert to high pH and ammonium bicarbonate is not corrosive at all...

Hi,

I have had leeching from the lines when using IPA before, had to by-pass the degasser- Fun!

IPA is now a bad solvent for the HPLC system? No. Can you please elaborate on what you saw, what problems it caused and a possible reason why (maybe the manufacturer told you IPA is incompatible with your degasser?)

Thanks.

sure, we were using MS detection and just saw allsorts of mess, loads of masses we should never have seen with that method. It seems to be general with the pvc type tubing on agilent 1100's.

unless our lab bought cheap-o tubing before i worked there!

A certain company who will remain nameless (to protect the innocent) sold us an LC-MS system many years ago. The installation requirements included a bottle of top-grade isopropanol from specific suppliers. I duly bought the bottle. It cost a fortune.

On installation, there were all sorts of strange mass peaks when we ran the isopropanol, and the engineer was convinced it was our bottle. Had we opened it before he arrived? Was it really the right grade? We tried our own good-grade IPA, and the problem was slightly less severe, but still there. So it was obviously us. Then we got some really low grade IPA from the stores, and everything was fine.

Years later, the same engineer admitted to me that they'd found it was their tubing that causes the trouble.

IPA is a very good cleaning agent, so it cleans impurities off new tubing, and washes them into the mass spec.

The good news is that the impurities rarely last for ever, so if you keep going, eventually even cheap isopropanol from stores looks clean enough. I have to add that the mass spec was, and is, excellent.