Laserfiche WebLink
<br />APR 2 5 2008 <br />Analytical Procedures - Level II <br />Transmission electron microscopylenergy dispersive X-ray spectrometry/selected area <br />electron diffraction (TEMIEDX/SAED) was employed in the analysis of the samples, <br />which were collected on 25 mm mixed cellulose ester air fitters. A portion of each fitter <br />was collapsed with acetone and etched in a plasma asher. The etched filter was then <br />coated with a thin layer of carbon in a carbon evaporator. A small piece of each filter was <br />placed onto a 3 mrn diameter copper TEM grid with the carbon side down. The sample <br />was then placed inside a Jaffe wick washer and treated with acetone to remove the filter <br />matrix and expose any inert material. <br />Ten grid openings on a 200 mesh TEM grid are searched for fibrous structures which, if <br />present are analyzed by SAED and EDX (elemental analysis). Level 11 protocol requires <br />SAED confirmation of all asbestos identifications. EDX confirmation is also required for <br />the first 5 chrysotile structures, the first 10 amphibole structures, and every tenth structure <br />after the 5 or 10 structure minimum is met. The morphology of each structure is <br />determined and the length and diameter of any asbestos strictures is recorded- <br />Asbestos fibers, bundles, clusters, and matrices were identified and recorded. These <br />asbestos structures have been defined in Yamate et al., as follows: <br />Fiber: is a structure having an aspect ratio of 3:1 or greater with <br />substantially parallel sides. <br />Bundle: is a structure composed of three or more fibers in a parallel <br />arrangement, with each fiber closer than the diameter of one fiber. <br />Cluster: is a structure with fibers in a random arrangement such that all fibers <br />are intermixed and no single fiber is isolated from the group. <br />Matrix,. is a fiber or fibers with one end free and the other end embedded or <br />hidden by a particulate. <br />If more than 100 asbestos structures are identified and confirmed on a sample, Level 11 <br />analysis may be terminated after completion of the grid opening which contains the 100th <br />structure. <br />Equations Used for Calculations <br />Area Anaf`fzed, mm7 = # GO counted x Average GO Area (mm) <br />Concentration s1CG = *Asbestos Structures x---- x E`; Filter Area tmm2) 1L <br />----• ---- x - <br /># GO Counted - Vafu~r`-e (t.) Average Aiee ;mm - 1(TO0 cc <br />Filter icading, s1rn n2 _ # Asbestos Structures <br />Aea Analyzed (mm } <br />GO = TEM grid openng