ABSTRACT

This chapter shows that 0.22 µm filter is dried and prepared according to the direct filter preparation procedure. Laboratory analysis procedures have been developed for a variety of sample collection media. The laboratory procedures are those currently being used by a laboratory routinely involved with dust analysis. In the laboratory, the unopened microvac cassettes are wet-wiped and then prepared for analysis under clean room conditions. The cassettes and filters are thoroughly rinsed with a 50/50 mixture of alcohol and particle-free water and filtered through a 1 mm mesh sieve. The original collection filter is used during the sample collection procedure but otherwise is not used in the analysis. In the laboratory, the outsides of the tins are wiped clean with a moistened cloth in a high-efficiency particulate air (HEPA) hood. The initial specimen preparation takes place in a clean HEPA- filtered negative pressure hood to avoid possible contamination of the laboratory and personnel.