The TEOM Series 1500 PMA Reaction Kinetics Analyzer incorporates an inertial balance patented by Thermo. It measures the mass of a sample bed by measuring the frequency changes of a tapered element (figure at right). The sample flow passes through upstream sample preparation hardware, then through the material contained in the sample bed at the end of the tapered element, where gas-material reactions take place, and then continues through downstream sample handling hardware.

As the mass of the material in the sample bed changes with respect to time, the tube's natural frequency of oscillation reflects these variations. Mass increases result in a decrease of the tube's natural oscillating frequency, while reductions in mass cause the frequency to increase. A direct relationship exists between the tube's change in frequency and mass of the sample bed. This inertial methodology is a more fundamental means of measuring mass than the use of gravity. This technique enables highly precise and accurate mass determinations, providing more resolution than conventional microbalances.

The TEOM mass transducer does not require recalibration because it is specially designed and constructed from non-fatiguing materials. Calibration may be verified, however, using a known mass. This procedure can be readily preformed in the field or at the factory