Can your FT-IR do this?
A gas cell contained two gases ‘A’ (500 ppm) and ‘B’. At time zero, pure gas ‘B’ flowed into the cell and a mixture of ‘A’ and ‘B’ was allowed to flow out. With a fixed gas cell size and a given gas flow rate, it took less than 3.2 seconds for gas ‘A’ to reach minimal levels.