Abstract: A method and apparatus for the continuous and automatic analysis of a process stream is disclosed. A tunable laser capable of delivering high intensity infrared radiation at a predetermined wavelength is used to monitor the crosslinker content of a room temperature vulcanizable composition (RTV) during its manufacture. Methyltriacetoxysilane is a crosslinking component in acetoxy system RTV's and contains a carbonyl group which absorb infrared radiation very strongly at certain predetermined frequencies. Determination of the amount of infrared absorption by the crosslinker is directly related to the determination of the crosslinker content in a process stream of RTV.