Chromatography Forum

Hi all,

I was wondering about these contaminant low molecular weight ions present in the ion source. I did clean the spray chamber with 50/50 (h20,ipa). It has been a little over 6 months since I last cleaned the ion transfer capillary.

We run mostly in the positive mode and some of the samples we run contain Triton X-100. (Presumable problem)

Does anybody have any idea how to bring down the baseline of some of these high abundance contaminant ions that seem to be lingering in the source? (Around 200-300 Da)

I spoke with some colleagues who have recommended to purge and flush the entire LC system with a series of rinses and harsher organics to clear up any tubing or components with any adhered Triton? Is this a best practice?

I have attached a MS2 Fullscan image of the tuning solution, in the image below.

Any idea guys?? Please share some information on what sort of contaminant ions you observe on your system and the best practices for reducing the species.

Many Thanks!

If you see the contamination while the LC-flow is switched to waste, then you have to clean the source. If this does not help, you'll have to clean the capillary. We have to do this every few months. Vent the System, take it out carefully and sonicate it for a few minutes in a plastic flask in alconox solution. Rinse with distilled water, dry, reinstall. The procedure takes about 30 minutes and 1 to 2 hours for the MS to stabilize. Tune and see if it is better.