ASBESTOS, CHRYSOTILE by XRD
Mg3Si2O5(OH)4
MW: ca. 283
METHOD: 9000, Issue 2
EPA Standard (Bulk):
CAS: 12001-29-5
9000
RTECS: CI6478500
EVALUATION: FULL
1% by weight
PROPERTIES:
Issue 1: 15 May 1989 Issue 2: 15 August 1994
solid, fibrous mineral; conversion to Forsterite at 580 °C; attacked by acids; loses water above 300 °C
SYNONYMS: Chrysotile
SAMPLING BULK SAMPLE:
1 to 10 grams
SHIPMENT:
seal securely to prevent escape of asbestos
SAMPLE STABILITY:
indefinitely
BLANKS:
none required
ACCURACY RANGE STUDIED: 1 to 100% in talc [1] BIAS:
negligible if standards and samples are matched in particle size [1]
ˆ ): OVERALL PRECISION (S rT
unknown; depends on matrix and concentration
ACCURACY:
± 14% to ± 25%
MEASUREMENT TECHNIQUE:
X-RAY POWDER DIFFRACTION
ANALYTE:
chrysotile
PREPARATION:
grind under liquid N 2; wet-sieve through 10-µm sieve
DEPOSIT:
5 mg dust on 0.45-µm Ag membrane filter
XRD:
Cu target X-ray tube; Optimize for intensity; 1° slit; Integrated intensity with background subtraction
CALIBRATION:
suspensions of asbestos in 2-propanol
RANGE:
1 to 100% (w/w) asbestos
ESTIMATED LOD: 0.2% asbestos in talc and calcite; 0.4% in heavy X-ray absorbers such as Fe 2O 3 PRECISION (Sr):
0.07 (5 to 100%); 0.10 (@ 3%); 0.125 (@ 1%)
APPLICABILITY: Analysis of percent chrysotile asbestos in bulk samples.
INTERFERENCES: Antigorite (massive serpentine), Chlorite, Kaolinite, Bementite, and Brushite interfere. X-ray fluorescence and absorption is a problem with some elements; fluorescence can be circumvented with a diffracted beam monochromator, a nd absorption is corrected for in this method.
OTHER METHODS: This is P&CAM 309 [2] applied to bulk samples only, since the sensitivity is not adequate for personal air samples. The EPA Test Method for the determination of asbestos in bulk insulation samples is similar to this one [3]. Me thod 7400 is an optical counting procedure for airborne fibers in personal samples. Methods 7402 (Asbestos by Transmission El ectron Microscopy) and 9002 (Asbestos by Polarized Light Microscopy) are also useful for positive identification of asbestos.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
