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How much more sensitive is API 4000 or 3000 than 2000?
Posted: Thu Feb 23, 2006 4:37 pm
by shangyer
I can reach the sensitivity of 1 pg on column with API 2000, with ESI. I am not sure if I can go any much further with API 4000, like 0.05 pg on column. Any thoughts?
Posted: Thu Feb 23, 2006 5:43 pm
by Schmitty
Depending on the analyte, of course, the 5000 is 2-3X as sensitive as the 4000. The 4000 is ~10X more sensitive than the 3000. I have not heard any laboratory conjecture about the relation of the 2000 to any other instrument (I didn't even know there was a 2000
).
How much more sensitive is API 4000 or 3000 than 2000?
Posted: Wed Mar 01, 2006 5:29 pm
by guenzia
In absolute terms, the answer is not very easy: very often sensitivity depends on the molecule you analyze, on how well the instrument is maintained, and on how the quadrupoles were born / produced!
I would say, however, that the Sciex API2000 is about 5 times less sensitive than the API3000 in ESI positive. I agree with the answer of Schmitty for the difference between 3000 and 4000, and between 4000 and 5000. On the other hand, in ESI negative, the difference between a 2000 and a 3000 can be as large as 100-fold! (there are in addition huge differences among different 2000s in ESI negative)
Posted: Fri Mar 03, 2006 9:27 pm
by MG
I moved a couple of methods from a 3000 to a 4000. Everything was reoptimized for the 4000 in both cases, but the same LC conditions and type of LC system were used on both. The ESI negative method was about 10x more sensitive on the 4000. The APCI negative method was about the same sensitivity on both instruments.