Compact, portable benchtop analyzers for analyzing gases at atmospheric pressure. They are particularly used for applications in chemical processes, in the semiconductor industry, metallurgy, fermentation, catalysis, freeze-drying and in environmental analysis. The low detection limit (depending on the mass range) of up to 100 ppb, the low gas consumption of 1 - 2 sccm and the fast measuring time (up to 1 ms/u) characterize the new analytical instruments.