Laser microprobe mass analysis was applied for the analysis of organic Impurities at the surface of asbestos fibers. Benzo[a]pyrene was adsorbed from the gas phase and from a benzene solution, benzidine from aqueous solution and N,Ndlmethylanlllne from benzene. By use of laser desorption conditions these compounds, and In the case of N,N-ü\methylanlline Its oxidation products, such as Methyl Violet, could easily be detected.

Standard U.I.C.C. asbestos samples are often contamlnated wlth organic addltlves of polyethylene packing material. Laser microprobe mass analysis when used at low laser lrradlance eondltlons is able to detect specific organlc surface contaminants on indivldual fibers wlth detectlon llmlts of better than 500 pg g-' and wlth a shot-to-shot reproduclblllty of ca. 20%.

The adsorption-desorption behaviour of aliphatic alkylamines for asbestos was studied. A high affinity and strong adsorption characteristics, controlled by Van der Waals interaction and steric hindrance were obtained. For the R.N€I-.CI (1 < n C 4) doped asbestos fibres, the laser microprobe mass analysis (LAMMA) technique was used to analyse selectively the individual asbestos surface loadings. Only for quaternary (and tertiary at higher concentrations) ammonium products, could a semi-quantitative picture of the organic asbestos surface covering be observed.

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