NIOSH
HAZARD REVIEW
Health
Effects of Occupational Exposure
to
Respirable Crystalline Silica
|
Table
6. XRD* sampling and analytical methods for crystalline
silica
|
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|
Item
|
NIOSH
Method 7500 |
OSHA
Method ID-142 |
MSHA
Method P-2 |
MDHS
51/2
|
|
Silica
polymorph
|
Quartz,
cristobalite, tridymite
|
Quartz,
cristobalite
|
Quartz,
cristobalite
|
Quartz
|
|
Sampler
|
10-mm
nylon cyclone,
1.7 L/min; Higgins-Dewell cyclone, 2.2 L/min |
10-mm
nylon
Dorr-Oliver cyclone, 1.7 L/min |
10-mm
nylon
Dorr-Oliver cyclone, 1.7 L/min |
Higgins-Dewell
cyclone,
1.9 L/min |
|
Filter
|
37-mm,
5-µm
PVC membrane |
37-mm,
5-µm PVC membrane
|
37-mm,
5-µm
PVC membrane |
37-mm,
5-µm
PVC membrane |
|
Volume
|
400–1,000
L; total dust <2 mg
|
408–816
L; total dust <3 mg
|
400–1,000
L; total dust <3 mg
|
>456 L; total
dust <2 mg |
|
Filter
preparation
|
RF
plasma asher, muffle furnace, or filter dissolution in THF
|
Dissolve
filter in THF
|
RF
plasma asher
|
None
|
|
Redeposition
|
On
0.45-µm silver membrane filter
|
On
0.45-µm silver membrane filter
|
On
0.45-µm silver membrane filter
|
None
|
|
Drift
correction
|
Silver
internal standard
|
Silver
internal standard
|
Silver
internal standard
|
External
standard
(e.g., aluminum plate) |
|
X-ray
source
|
Cu
Kα; 40 kV,
35 mA |
Cu
Kα; 40 kV, 40 mA
|
Cu
Kα; 55 kV,
40 mA |
Cu
Kα; 45 kV,
45 mA |
|
Calibration
|
Suspensions
of SiO2 in 2-propanol (deposited on silver membrane filter)
|
Suspensions
of SiO2 in 2-propanol (deposited on silver membrane filter)
|
Suspensions
of SiO2 in 2-propanol (deposited on silver membrane filter)
|
Sampling
from a generated atmosphere of standard quartz dust
|
|
Proficiency
testing
|
PAT
|
PAT
|
PAT
|
WASP
|
|
Range
(µg quartz)
|
20–2,000
|
50–160
(validation range)
|
20–500
|
50–2,000
|
|
LOD
(µg quartz) |
5
(estimated)
|
10
|
5
|
3
|
|
Precision
|
___
RSD= 0.08 50–200 µg |
__
CV= 0.106 @ 50–160 µg |
CV
= 10% @ 20–500 µg
|
CV
= 5% @ 50 µg
|
| *Abbreviations:
Cu = copper; CV = coefficient of variation (equivalent to RSD); __ CV = pooled coefficient of variation; Kα = electron ionization energy; kV = kilovolt(s); LOD = limit of detection; mA = milliampere(s); MDHS = Methods for the Determination of Hazardous Substances (Health and Safety Executive, United Kingdom); MSHA = Mine Safety and Health Administration; NIOSH = National Institute for Occupational Safety and Health; OSHA = Occupational Safety and Health Administration; PAT = proficiency analytical testing; PVC = polyvinyl chloride; RF = radio frequency; RSD = relative standard deviation; ___ RSD = pooled relative standard deviation (equivalent to CV); THF = tetrahydrofuran; WASP = Workplace Analysis Scheme for Proficiency; XRD = X-ray diffraction. |
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