Detector Gain

[sonicboom12345]

Hello,

I am a new graduate student pursuing a PhD in analytical chemistry. I am working with GC-MS a lot, and I would certainly value this forum to answer any questions I have as I go!

My question is, what is detector gain? What purpose does it serve? If a detector gain calibration fails, what does that mean?

[Don_Hilton]

Gain in any amplifier stage is the increase in output signal over input signal. In a mass spectral detector this would be the electrical curent that comes out of the detectror as the result of ions striking the the detector.

In an electron multiplier (the common type of mass spec detector) an increasse in voltage across the elements of the detector increases the ratio of output current to the incoming ion current. However, the increased voltage also results in increased electrical noise and decreased detector life.

A failure in detector gain could mean one of several things. If you specify the instrument you are using, someone familiar with that type of instrument cangive you specific details.