The TGA100 was replaced with the TGA100A, which was replaced with the TGA200. Upgrades are now available to operate a TGA100 analyzer with a thermoelectrically cooled (TEC) laser, enabling the analyzer to no longer require liquid nitrogen refills. Contact Campbell Scientific for more information. The TGA100 Trace-Gas Analyzer measures trace-gas concentration in an air sample using tunable diode laser absorption spectroscopy (TDLAS). This technique provides high sensitivity, speed, and selectivity. The TGA100 is a rugged, portable instrument designed for use in the field. It can measure one of a large number of gases by choosing appropriate lasers and detectors. It incorporates several features that make it ideal for measuring fluxes of trace gases using gradient or eddy-covariance techniques.