Meiji Techno MT6800 series asbestos PLM – PCM combination microscopes for fibre identification and counting.
Binocular asbestos combo [polarising/phase contrast] (PLM-PCM) microscope, with MA936 Strain Free Plan 10X & MA936D Dispersion Staining 10X, U Plan MA841 40X phase. Phase/brightfield condenser HWF 12.5X eyepieces one focusing with Walton Beckett graticule, one 12.5x cross line, one plain. 6V 30W halogen illuminator.
Trinocular asbestos combo [polarising/phase contrast] (PLM-PCM) microscope with 1X ‘C’ mount & phototube, MA936 Strain Free Plan 10X & MA936D Dispersion Staining 10X, UPlan MA841 40X Phase. Phase/brightfield condenser HWF 12.5X eyepieces one focusing with Walton Beckett graticule, one 12.5x cross line, one plain. 6V 30W halogen illuminator.
Phase Contrast Dispersion Staining:
MT Series PLM asbestos microscopes use the phase contrast method for dispersion staining and include a condenser with centerable phase slider for its annulus dispersion staining objectives. This technique requires that the analyser and compensator be withdrawn, the illumination increased, and the dispersion objective with phase ring in the back focal plane be inserted together with the corresponding phase annulus in the condenser.
Different colours will be observed when the fibre is oriented parallel or perpendicular to the vibration / polariser direction. This method is easier to interpret than the objective stop method used by the older ML Series due to the presence of two complementary colours in the same image, so that the wavelength of the refractive index match can be more closely determined.
Below are photos of results using the different methods. Further details are available in the following guide: Asbestos: The analysts’ guide for sampling, analysis and clearance procedures
- 1. Dispersion staining. (2009, October 19). In Wikipedia, The Free Encyclopaedia. Retrieved 22:48, March 19, 2010: Article
2. Occupational Health & Safety Information Service (2005, March). Asbestos – The Analysts Guide for Sampling, Analysis and Clearance Procedures. Health & Safety Executive.