Sensitivity of lc-ms/ms sysytems

[shashank_03]

Hi,
can any one tell me which of the following system is best in terms of sensitivity and reproducibility
1)AB SCIEX API 4000
2)WATERS MICROMASS QUATTRO PREMIER XE .

Waiting for your comment
shashank

[yangz00g]

I have used both.

If using reserpine (+ESI) as the sensitivity check standard, they are vitually the same with 4000 slightly higher.

Premier XL polarity switching delay (+ to -) is 20ms vs 700 ms for API. Premier maximum scan rate is twice that of 4000.

API can use shorter MRM dwell time

Reproducibility is sbujective to individual opinion or instrument.