DOH/DEP asbestos fact sheet draft, 105 Duane Street

NYC 9/11 Public Portal Document 12/11/2001 17:06 FAX 212 353 8306 ATC 1 1010

D 5755 12.62.4 Place the three TEM grid sample filter mepara- TEM at a calibrated screen magnification of between 15 000 Lions on the same piece of lens tissue in the Jaffe washer. and 20 000X. Typically measure one grid opening for each 12.6.2.5 Place the lid on the Jaffe washer and allow the grid examined. Measure grid openings in both the x and y system to stand for several hours. directions and calculate the area. 12.7 Alternately, place the grids on a low level (petri dish 14.4 Pre-calibrated TEM grids are also acceptable for this filled to the '/a mark) DMF Jaffe washer for 60 min. Add test method. enough solution of equal parts DMF/acetone to fill the washer to the screen level. Remove the grids after 30 min if 15. TEM Method they have cleared, that is, all filter material has been removed from the carbon film, as determined by inspection in the 15.1 Microscope settings: 80 to 120 kV, 15 000 to TEM. 20 OOOX screen magnification for analysis (7.2). 12.8 Carefully remove the ' grids from the Jaffe washer, 15.2 Analyze two grids for each sample. Analyze one-half allowing the grids to dry before placing them in a- clean of the sample area.on one sample grid preparation and the marked grid box. remaining half on a second sample grid preparation. 15.3 Dererminacion of Specimen Suitability_ 13. TEM Specimen Preparation of Polycarbonate (PC) 15.3.1 Carefully load the TEM grid, carbon side facing up Filter (in the TEM column) with the grid bars oriented parallel/ 13.1 Cover the surface of a clean microscope slide with perpendicular to the length of the specimen holder. Use a two strips of double-sided adhesive tape. hand lens or loupe, if necessary. This procedure will line

up

13.2 Cut a strip of filter paper slightly narrower than the the grid with the X and y translation directions of the width of the slide. Position the filter paper strip on the center microscope. Insert the specimen holder into the microscope. of the length of the slide. 15.3.2 Scan the entire grid at low magnification (250X to 13.3 Using a clean, curved scalpel blade, cut a strip of the 1000X) to determine its suitability for high magnification PC filter approximately 25 by 6 mm. Use a rocking motion analysis as specified in 15.3.3. of the scalpel blade to avoid tearing the fiber. Place the PC 15.3.3 Grids are acceptable for analysis if the following strip particle side up on the slide perpendicular to the long conditions are ntet: axis of the .slide. The ends of the PC strip must contact the 15.3.3.1 The fraction of grid openings covered by the double sided adhesive tape, Each Slide can hold Several PC nepha section is at least SO %. strips. With a glass marker, label each PC strip with the 15.3.3.2 Relative to that section of the grid covered by the individual sample number. carbon replica, the fraction of Intact grid openings is greater 13.4 Carbon coat the PC filter strips as discussed in than 50 %. 12.4.2. PC filters do not require etching. I5.3.3.3 The fractional area of undissolved filter is less than 10%. NoiE? Z (aatton-Do not overheat the Rlter saedons while carbon 15.3.3.4 The fraction of grid openings with overlapping or coating. folded replica film is less than 50 %. 13.5 Prepare a Jaffe washer as described in 12.5, but fill 15-3.3.5 At least 20 grid openings, that have no overlap- the washer with chloroform or 1.methyl-2pyrrolidone to the ping or folded replica, are less than 5 S covered with holes level of the screen. and have less than 5 % opaque area due to incomplete fitter 13.6 Using a clean curved scalpel blade, excise three, dissolution. 3-mm square filter pieces from each PC strip. Place the filter 15.4

DeWmfaarlon of Grid

Opening Suitability:

squares carbon side up on the shiny side of a TEM grid. Pick 15.4.1 If the grid meets acceptance criteria, choose a grid up the grid and filter auction together and place them on the opening for analysis from various areas of the grid so that the lens tissue in the Jaffe washer. entire grid is represented. Determine the suitability of each {3.7 Place the lid on the Jaffe washer and rest the grids in individual grid opening prior to the analysis. place for at least 4 h. Best results are obtained with longer 15.42 The individual gild opening must have less than wincing times, up to 12 h. 5 % hobs over its area. 13.8 Carefully remove the grids from the Jaffh washer, 15.43 Grid openings must be leas than 25 % covered with allowing the grids to dry before placing them in a clean, particulate matter.

marked grid box. 15.4.4 Osrld openings must be uniformly loaded. 15.5 Observe and record the orientation of the grid at 80 14. Grid Opening Measnremeets to on

150,X. a grid map

14.1 TEM grids must have a known grid opening area. record sheet

along with

the

location

of the grid openings that are examined for the analysis. If Determine this area as follows: indexed gr ids

are

used, a

14.2 Measure at least 20 grid openings in each of 20 map is not grid

required, but th e.

identifying coordinates of the grid square must be recorded. random 75 to 100 µm (200-mesh) copper grids for a total of 400 grid openings for every 1000 grids used, by placing the 16. Rccording

Dt Rules

20 grids on a glass slide and examining them under the 16.1 Record on the count sheet any continuous grouping optical microscope. Use a calibrated graticule to measure the of particles in which aq asbestos fiber is detected. Classify average length and width of the 20 openings from each of the asbestos structures as fiber, bundles, dusters, or matrices as individual grids From the accumulated data, calculate the defined in 52 average grid opening area of the 400 openings. 16.2 Use the criteria for fiber, bundle, duster; and matrix 143 Grid area measurements can also be made theat

identification, asdesaibedinthe USEPAArbestos-Co rtafaing

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