Quantitative IR-ATR spectrometry of asbestos fibers on membrane filters

Abstract

, 441 (1984). 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 kg, 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 Cs 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 (Al)/A(AZ) where A, < A,, should decrease with fiber dimension.,.The ATR signal at 303 cm-I, corresponding to a lattice vibration, varies linearly with fiber concentration up to 100 pg/cm2, whereas the intensity of this band relative to the OH stretching band at 3690 cm-' 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. Une analyse du phCnomkne ATR pour un certain recouvrement de fibres indique que le rapport logarithrnique de la rCflectivitC varie avec la concentration a la surface C tel que:oh Cs est la concentration pour une monocouche de fibre et r le diamktre moyen de la fibre. Pour une concentration d e surface suffisante, un plateau sera obtenu plus rapidement pour les courtes longueurs d'ondes et pour les fibres ayant un rapport longueur/diamktre ClevC. Nous pouvons prCdire que I'absorption relative A(Al)/A (A2), oh A , < A,, doit dirninuer en fonction de la dimension des fibres.Le signal ATR i 303 cm-I, caractkristique de la vibration de la maille cristalline, varie IinCairement avec une concentration de 100 pg/cm2 de fibres tandis que les rapports des bandes d'absorption de 303 cm-,13690 cm-' (3690 crn-' = vibration OH) nous donnent plutBt une fonction monotone representative de la morphologie des fibres.Les niveaux d'empoussiCrage et la morphologie moyenne des fibres peuvent Ctre ttablis par ATR, et les rksultats sont compatibles avec ceux de la microscopie optique et de la microscopie Clectronique.

Real-Time Identification and Characterization of Asbestos and Concrete Materials With Radioactive Contamination

“…To date, asbestos has been analyzed by several different methods, including optical methods such as X-ray powder diffraction (Hu et al 1996;Hrijac et al 1997) and infrared spectroscopy (Ghosh 1978;Kimmerle et al 1984). The major problems with existing optical methods are the spectral inferences and a lack of portability for field application.…”