Hello all,
I would like to ask about the gas chromatography GC ms, which minimum area variation is measurable (maximum and minimum area accuracy) and analyzer sensitivity (minimum and maximum range).
For example, I would like to see if the difference in concentration for a gas between the initial state and the final state is 40 mole/m3, is this measurable or not.
Thanks in advance
Hello Khaled,
The signal (or the peak area) in GC-MS reflects the concentration of the targeted compound in each injection, and the sensitivity is dependent on the compound itself.
Typically, quantitation from ppb to ppm level (μg/L to mg/L) can be achieved for common GC-MS.
Special sample injection tools are needed if you want to measure the concentration of gas directly. For example, needle-trap and solid-phase micro-extraction (SPME) can be applied to sample volatile chemicals.
Direct gas injection is also applicable in some cases, and a gas sampler is required. (depending on the concentration of the interested compound).
Depending on compound (and instrument) currently I would expect the systems are able to detect about 1 pg of compound. - now the rest is dependent on You injection technique. I have been running injection volumes from 0.1-50 µL solvents in routine.
A bit above the absolute limit of determination I would expect 10% relative standard deviation (lower RSD can be achieved if using internal standards).
I hope this helps
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