偏光显微镜法在空气粉尘中石棉纤维鉴别中的应用

本文采用偏光显微镜法鉴别空气粉尘中的微量石棉纤维。经滤膜收集的粉尘样品通过高温灰化及酸洗过程去除大部分干扰物质,经乙醇分散后均匀沉积在玻璃片上,滴加具有固定折射率的浸油制成试片。在正交偏光系统下观察到粉体中存在纤维状颗粒,且纤维呈现四次平行消光特性,比对6种常见石棉的偏光显微镜图,综合分析试样粉尘的光学性质,推断样品中含有温石棉。

Application of Polarizing Microscopy Method for Identification of Asbestos Fiber in Air Dust

In this paper, the micro asbestos fibers in air dust were identified by polarizing microscope. The dust samples collected by the filter membrane were treated by high-temperature ashing followed by acid washing to remove most interference substances. After being dispersed by ethanol, the dust samples was uniformly deposited on glass sheet to prepare test piece by dripping impregnation liquid with certain refractive index. The fibrous particles were observed in powder under orthogonal polarization system. Moreover,the fibers exhibited the characters of quartic parallel extinction. Compared with the polarizing microscope spectra of six kinds of common asbestos, the optical properties of sample dust were analyzed comprehensively, and it was shown that the sample contained chrysotile asbestos.