Chromatography Forum

Hello,

I have a Shimadzu QP 5000 and recently we had an air leak that lead to several issues. I have cleaned the MS and replaced all of the parts of my injector and trimmed the column a bit on the injector side. My tunes look good and my pressure is steady however I cannot get my sensitivity back to where it once was. Is this a column issue? What do you think?

Thanks

Try with a manual injection, different syringe.

[quote="Consumer Products Guy"]Try with a manual injection, different syringe.[/quote]

I have, no difference, sorry forgot to include that.

What is the condition of the filaments? Have you tried switching to the second filament to see if the response is better? The QP-5000 has a ribbon filament instead of a wire, and if the filament warps or wrinkles the sensitivity can be affected.

[quote="Ron"]What is the condition of the filaments? Have you tried switching to the second filament to see if the response is better? The QP-5000 has a ribbon filament instead of a wire, and if the filament warps or wrinkles the sensitivity can be affected.[/quote]


The filaments were new in MArch and switching them doesn't seem to make a difference. Talking to another guy from Shimadzu he lthinks it could be a ferrule issue in the inlet or and electrical phenomenon?

LWC,

Being that one of the last things you did was trim the column, are you sure you got the column position in the inlet correct? Can make a huge difference in sensitivity. Split or splitless and what kind of liner?

Best regards.