4F - CaCO3

0.2 g sample is thermally decomposed in a resistance furnace in a pure nitrogen environment at 1000 ^°C, using an ELTRA CW-800, directly releasing CO₂.H₂O is removed in a moisture trap prior to the detection of carbon dioxide in the IR cell. Carbon dioxide absorbs IR energy at a precise wavelength within the IR spectrum.  Energy from the IR source is absorbed as the gas passes through the cell, preventing it from reaching the IR detector. All other IR energy is prevented from reaching the IR detector by a narrow bandpass filter. Because of the filter, the absorption of IR energy can be attributed only to carbon dioxide (CO₂). The concentration of CO₂ is detected as a reduction in the level of energy at the detector. CaCO₃ is calculated from CO₂.