Quantitative IR-ATR spectrometry of asbestos fibers on membrane filters

• Published in: Canadian journal of chemistry Vol. 62; no. 3; pp. 441 - 451
• Main Authors: Kimmerle, F. M, Noël, Luc, Khorami, Jaleh
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.03.1984; National Research Council of Canada
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; Spectrometric and optical methods; Assay; Infrared spectrometry; Reflection spectrometry; Membrane filter; Chemical analysis; Total attenuated reflection; Nondestructive testing; Asbestos fiber; Identification; Polyvinyl chloride
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v84-076

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  < λ 2 , should decrease with fiber dimension.The ATR signal at 303 cm −1 , corresponding to a lattice vibration, varies linearly with fiber concentration up to 100 μg/cm 2 , whereas the intensity of this band relative to the OH stretching band at 3690 cm −1 is a monotonic function, representing the fiber morphology. Dust levels and fiber morphology established from the IR-ATR spectroscopy are consistent with measurements by light and electron microscopy.