[edwards]

Hi,

I have looked up the sentivity of a mass spectrometer in its manual and was wondering whether someone could actually tell me what it means.

1pg (5uL injection of 0.2 pg/uL) reserpine at 300uL/min flow rate 50:1 S/N- RMS.

Can I just say the the LOD is 1 pg? do the conditions have to be included when quoting sentivity specifications?

[JGK]

Mass spec sensitivity is pretty compound dependent (vill vary dramatically depending on the analyte). They have give you an example of the sensitivity forreserpine.

They injected 5 µL of a 0.2 pg/µL STD (total 1 pg in the injection) the signal to noise ratio for the peak was 50:1. For quantification, signal to noise ratios should be > = 10:1. For limit of detection, , signal to noise ratios should be ~3.3:1.

[marquis]

Sorry to say this.  Before you believe this number, see if the manufacturer will run the samples in their lab and/or give you the chromatograms.  If possible, do this with their instrument configured exactly as yours is configured.

I've run many detection limit tests in the lab.  Often times, the numbers I get are different from the manufacturers.  Not surprisingly, my detection limits are usually higher than theirs. 

Caveat emptor!