Bulk Sample Chart
An Organizational Chart to Guide Sample Preparation for Polarized Light Microscopy (PLM) Analysis of Bulk Samples for Asbestos
Bharati Lakshmi and Mary Helen Scott
Marine Chemist Service, Inc., 11850 Tug Boat Lane, Newport News, VA 23606-2527
A microscopist in an asbestos laboratory analyzing bulk samples for asbestos by PLM encounters a variety of samples on a daily basis. In this analytical method, sample preparation is a very important step in sample analysis. One slide preparation technique definitely is not suitable for all samples. Recognizing this limitation, NVLAP (National Voluntary Laboratory Accreditation Program) requires the laboratories to have written procedures for dealing with samples “in which the fibers are heavily coated with binders that hinder analysis” and “that are semi- or non-friable”. Generally PLM laboratories prepare lengthy procedures separately for each type of material like floor tile, roofing, ceiling tile, etc.
Here we describe a chart that combines various methods suitable for different types of bulk samples generally received by an asbestos laboratory. This chart encompasses a variety of samples and procedures for preparing those samples that work best based on the nature of the binder. This chart is concise and easy to read and follow. It can also be used to train new analysts in sample preparation techniques. Additionally, the “Comments” column gives hints about the nature of samples and what type of material can be expected to contain asbestos and how to examine the sample.
For the complete whitepaper, please contact Dr. Lakshmi.