This ten method establishes a procedure to determine the percent silica-producing volatiles present m beat cure silicone or one component RTV sealant. Silica producing volatiles are contributor? to the fouling of oxygen sensor systems used in the control of vehicle emissions. As a contributing source of contamination, the volatile potential of silicone can be accurately monitored by the use of this procedure. Utilizing this method in conjunction with a realistic maximum volatility tolerance level for end use material can help minimize the risk of oxygen sensor disfunction.

The procedure consists of 4 baste steps: 1) the silicone is cured to its elastomenc form, 2) the volatiles are extracted from the cured material 3) the extract is separated and measured by gas chromatography (GO and 4) the GC results are quantified using a .siioxane calibration. The volatile silicones from a commercial silicone are primarily cyclo dimethyl-siioxane. Other species present having GC retention times similar to those of the cycics are assumed to be silicone as well.l

Safety. This method may involve hazardous materials, operations and equipment. This procedure does not propose to address all the safety problems iviiaiirri with its use. Is is the responsibility of the user of this procedure to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.