by
weber » Thu Dec 03, 2009 5:59 pm
Thanks for your comments!
We did the following:
1. Rinse the source with isopropanol, water, 25% nitric acid (15'), water (1,5 h), (of course NOT attached to the ms).
2. according to an advice of the chemist of the manufacturer cleaning of the whole ion path including both quadrupoles
the source seemed then to be clean so far. Nearly no 102-peak.
But the hplc system still produces a peak of > 10^8.
So .....
3. Exchanging all peek-capillaries
4. ultrasonic of the rotor seals in isopropanol
5. Rinse the whole hplc with 25% nitric acid for 15 Minutes
6. Rinse the whole system with water, purge the pulse damper several times
7. Rinse the system one night with 50% isopropanol/water with 0.1% FA
After this procedure, the TEA background went down from originally >2x10^8 to about 10^6. The sensitivity was about half of we are used to, but we can measure already.
One day later, the sensitivity is about what we expect it to be.
So it was a really laborious experience. Fortunately we used this TEA only for about 3 hours.
Thanks a lot!