Quantitative IR-ATR spectrometry of asbestos fibers on membrane filters

We have developed a new IR-ATR spectroscopic technique for the identification and quantification of fibers collected on PVC filters. This nondestructive method has a detection limit of about 10 μg, involves no sample preparation, and is relatively insensitive to nonserpentine dusts normally associated with the asbestos mining and milling industries.An analysis of the ATR phenomena for a fiber matt indicates that the logarithmic ratio of the reflectivity varies with the surface concentration C as: where C s is the concentration for a monolayer of fiber, r the mean fiber diameter. Thus, the absorption should reach a plateau when a sufficient thickness is obtained, and this nonlinear region should be attained at lower wavelength, and at lower concentrations for long fibers having a high aspect ratio. We further predict that the relative absorption A(λ 1 )/A(λ 2 ) where λ 1