Page:NIOSH Manual of Analytical Methods - 7506.pdf/1

 BORON CARBIDE

B 4C

MW: 55.26

METHOD: 7506, Issue 2

CAS: 12069-32-8

EVALUATION: PARTIAL

OSHA : no standard NIOSH: no standard ACGIH: no standard

7506

RTECS: None

Issue 1: 15 May 1985 Issue 2: 15 August 1994

PROPERTIES: solid; d 2.51 g/mL; MP 2350 °C

SYNONYMS: None

SAMPLING SAMPLER:

MEASUREMENT

CYCLONE + FILTER (10-mm cyclone, Higgins-Dewell (HD) + 5-µm PVC membrane)

TECHNIQUE:

X-RAY POWDER DIFFRACTION

ANALYTE:

boron carbide

FLOW RATE:

HD cyclone: 2.2 L/min nylon cyclone: 1.7 L/min

ASH:

RF plasma asher

100 L @ 1 mg/m 3 1000 L

SUSPEND:

in 2-propanol

VOL-MIN: -MAX:

REDEPOSIT:

0.45-µm Ag membrane filter

SHIPMENT:

routine

XRD:

Cu target X-ray tube Optimize for intensity; 1° receiving slit Graphite monochromator; scintillation detector Slow step scan, 0.02°/10 sec Integrated intensity with background subtraction

CALIBRATION:

standard suspensions of B 4 C in 2-propanol

RANGE:

0.1 to 2 mg per sample

SAMPLE STABILITY:

stable

FIELD BLANKS:

2 to 10 field blanks per set

BULK SAMPLE:

required; area respirable or settled dust

ACCURACY RANGE STUDIED:

not studied

BIAS:

not determined

ˆ ): not determined OVERALL PRECISION (S rT ACCURACY:

ESTIMATED LOD: 0.05 mg per sample PRECISION (Sr):

0.04 [1]

not determined

APPLICABILITY: The working range is 0.2 to 4 mg/m 3 for a 500-L air sample. The method is specific for determining respirable boron carbide among other mine dusts.

INTERFERENCES: Titanium dioxide, silver, titanium diboride, niobium oxide, silver chloride interfere; also see APPENDIX A.

OTHER METHODS: This revises P&CAM 324 [1].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94