Gas chromatography with mass spectrometric detection
The GC-MS method is based on gas chromatographic separation of volatile compounds followed by mass spectrometric detection.
Operating principle:
the introduced sample evaporates in the chromatograph injector and is transferred to the column (completely or partially)
the most volatile substances pass through the column at different speeds, which results in their separation
for the passage of less volatile compounds through the column, its temperature is proportionally increased
from the column through a thermostatted interface connection enter the ion source, where they are ionized (usually by electron impact)
formed ions are directed into a mass analyzer, where they are separated by mass-to-charge ratio (m/z)
from the quadrupole, ions enter the detector, which determines their quantity
as a result of the analysis, a three-dimensional data array is obtained - each chromatogram point contains a mass spectrum
The main advantage of the method is the combination of highly efficient separation and identification. This allows for the rapid identification of volatile compounds in the most complex mixtures and matrices.
Other advantages of the method:
high selectivity (for individual ions) - allows increasing the efficiency of separation
high sensitivity: <1 picogram in selected ion monitoring (SIM) mode
the ability to simultaneously determine a large number of analytes of different nature
the possibility of rapid semi-quantitative analysis of volatile samples (gasoline, organic solvents, etc.) by the normalization method
