Chromatography Forum

Hi everyone, I'm playing with waters TQ detector for pesticide analysis.
I washed the column with 50% ACN to 90% ACN overnight and somehow there is now no analyte peaks.
I tried for many types of standard, and only background noise can be obtained.
Then, I checked the flow rate for washing column, and it is 0.5 ml/min. I am not sure if it is too high, cause I found there is a little solution leak from the top of probe sometime. ( Wondering if it is really a leakage, maybe I can take a photo if it comes again...)
I also used tune page with high selective analyte but again no signal observed.
What can I do to fix this up? I really need your respond or I will be beyond schedule. Thank you.

Hi,

You must verify the system is in working condition and the instrument tune report ion abundances and peak widths should match approximately the same settings as when the system was first installed or was in working order. Did you guys perform a recent tune? This is your starting ground, if not you could have some sort of problem going on with the detector or quadrupoles or something else and would require a complete diagnostics by the service engineer.

Are you guys maintaing vacuum? Did you prepare a fresh tuning solution? How is your gas supply, do you have enough collision cell gas and nebulizer gas? Is that an ESI source in positive polarity?

Hi, thank you for your reply. I checked everything and finally called the engineer for help.
The problem is that I really set flow rate too high, which making the inlet transfer tube broken and get off from the probe. So it means there is no injection to MS and of cause no signal can be found.
Anyways, I am glad that my MS is still alive and I can play with it again~
0.5 ml/min is too high for uplc-msms system, that's what I learn. =P