Sensitivity comparison - TSQ Quantum Classic vs. API 3000

[frangyan]

I need to buy an used LC/MS/MS for quantification of several biomarkers. Is API 3000 more sensitive? According to its datasheet of API 3000, 0.8 pg of a compound can have a peak with S/N of 150, while for Quantum Classic, 10 pg of reserpinep produce a S/N ratio of 150.

[lmh]

Beware of comparing S/N values from different manufacturers without checking that they are calculated in exactly the same way. Even within one software package (Xcalibur from Thermo), different integrators can produce S/N values for the same peak that differ by orders of magnitude.

Companies also differ in their optimism when they write specification sheets!

If you are buying an LC-MS, the manufacturers should be prepared to run some test samples for you. Make up an appropriate standard and matrix, and ask them to give you limit of quantification data by some reasonably standard method. Direct comparison of real data from your samples will be more reliable than a specification sheet.

[netsking]

Beware of comparing S/N values from different manufacturers without checking that they are calculated in exactly the same way. Even within one software package (Xcalibur from Thermo), different integrators can produce S/N values for the same peak that differ by orders of magnitude.

Companies also differ in their optimism when they write specification sheets!

If you are buying an LC-MS, the manufacturers should be prepared to run some test samples for you. Make up an appropriate standard and matrix, and ask them to give you limit of quantification data by some reasonably standard method. Direct comparison of real data from your samples will be more reliable than a specification sheet.

Thanks a lot.

[lmh]

sorry, didn't spot of course that this is a used instrument, but it may (should?) still be possible to get a very simple demo to check S/N on low concentration injections of a compound of your choice.