information about instrument sensitivity
Posted: Wed Sep 30, 2015 3:32 pm
by joselin
Hello, I am new to this forum and maybe someone can help me with some information I am not able to find on the internet. I am comparing different LC-MS/MS systems before contacting the sales representatives. I want to compare instrument detection limits/sensitivities from the manufacturers, but I wasn't able to find any specifications about the AB Sciex instruments (3500 and 4500). Do you know what S/N this instrument has for 1pg reserpine? Thank you.
Joselin
Re: information about instrument sensitivity
Posted: Wed Sep 30, 2015 11:05 pm
by James_Ball
Hello, I am new to this forum and maybe someone can help me with some information I am not able to find on the internet. I am comparing different LC-MS/MS systems before contacting the sales representatives. I want to compare instrument detection limits/sensitivities from the manufacturers, but I wasn't able to find any specifications about the AB Sciex instruments (3500 and 4500). Do you know what S/N this instrument has for 1pg reserpine? Thank you.
Joselin
I don't know the absolute sensitivities of the current models but I have the ABI 3200 and was told that the ABI 4000 was 4X more sensitive and the ABI 5000 was 10x more sensitive. Maybe they still work on the same principle with the incremental model numbers.
Re: information about instrument sensitivity
Posted: Tue Oct 06, 2015 4:41 pm
by lmh
in the end, for best results, you absolutely need to rely on your own own tests rather than published estimates: tell the manufacturers what conditions to use, and ask them to carry out runs under your direction. There are so many ways to fiddle this: opening up isolation widths on the precursor ion selection, etc. etc.; also, no matter how hard you try, each manufacturer will have expressed their results in slightly different ways (S:N calculated under different conditions!). This isn't malicious, it's just that there is no one way to do things. Also, sensitivity depends on compound in a complex way. The instrument that is most sensitive for reserpine may not be most sensitive for your target compound. If you do just want the ball-park figures, then actually contacting the reps is the best way; it's quicker than hunting through lots of brochures and trying to piece together some sort of overview.