Chromatography Forum

Hi everybody,
I am working with a LC-MS/MS TSQ Vantage HESI II. The instrument has been running properly during last 5 years but suddenly I faced a significant decrease in intensity and the system cannot get calibrated using polytyrosine due to low signal. Can anybody give me some information where the problem is?
Thank you in advance.

First thing I would do is do a clean of the front end optics.. Up to and including Exit lens on API stack.. Be very thorough on the S-lens and the inside of the orifices on the lenses.. Use MicroMesh 6000 or similar.

Also verify the metal needle in the Probe is not completely blocked or burned at the tip.

Good luck.

Dear leadazide,

Thank you very much for your invaluable information. I did as you had suggested and now the instrument is working properly.

Best regards

Glad to help! Feel free to ask again if you run into other issues.