Some macro and microscopic applications of dispersion staining as applied to industrial hygiene and air pollution

Abstract

Microscope accessories for the identification by dispersion staining of different forms of silicon dioxide varying in their toxicity have been described. The same equipment can also be used for the differentiation of various grades of beryllium oxide and different types of asbestos. Also described is a dispersion staining technique that does not require the use of a microscope. The usual refractive index liquids above approximately 1.52 in refractive index can be used for dispersion staining. However, in the case of very low index materials such as fused silica, tridymite, and cristobalite, the liquids commonly used do not have adequate dispersion. Mixtures of triethyl phosphate or tributyl phosphate with ethyl cinnamate should be substituted. Although this publication has been limited to the identification of the silicon dioxides, the beryllium oxides, and types of asbestos, it is applicable to the identification of other particulates in the index range of approximately 1.45–2.00.