The determination of chrysotile in insulation samples using combined TGA-GCA.
Proc North Am Thermal Analysis Soc Conf New Orleans Louisiana Oct 19- 21 Oct; 2(51):303-309
The Bureau of Mines particulate mineralogy unit. One of the objectives is to provide technical assistance on mineral particulate- related problems to other federal agencies. Quantification of the asbestos content in insulation and construction materials is necessary for the U.S. Environmental Protection Agency to evaluate the potential health risk from exposure to airborne fiber. Gas chromatographic analysis (GCA) of the effluent gases from a thermogravimetric analysis (TGA) balance can provide quantitative data concerning the composition of insulation samples. The GCA peak related to the dehydration of chrysotile occurs within the temperature range of 560 deg. to 660 deg. C. Using chrysotile standards, a linear relationship is obtained relating the summation of the peak heights for water evolved within this 100 deg. C range and the mass of chrysotile present in the sample. The use of a narrow 100 deg c range to acquire the dehydration data for chrysotile minimizes interferences from hydrates that decompose at lower temperatures and amphiboles that decompose at higher temperatures, for examples, gypsum and amosite. GCA data also allow avoiding misinterpreting tga thermograms for chrysotile when actual caco3 decomposition is involved by resolving weight losses in the dehydration range of chrysotile into components of water and co2.
Proc. North Am. Thermal Analysis Soc. Conf. New Orleans, Louisiana, Oct. 19- 21,V. 2, No. 51 Pp 303-309