Page:NIOSH Manual of Analytical Methods - 7505.pdf/1

 LEAD SULFIDE

PbS

MW: 239.25

METHOD: 7505, Issue 2

CAS: 1314-87-0

7505

RTECS: OG4550000

EVALUATION: PARTIAL

OSHA : 0.05 mg (Pb)/m 3 NIOSH: <0.1 mg (Pb)/m 3; blood Pb ≤ 60 µg/100 g ACGIH: 0.15 mg (Pb)/m 3

Issue 1: 15 February 1984 Issue 2: 15 August 1994

PROPERTIES: solid; d 7.5 g/mL; MP 1114 °C

SYNONYMS: galena (mineral)

SAMPLING SAMPLER:

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

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

MEASUREMENT TECHNIQUE:

X-RAY POWDER DIFFRACTION

ANALYTE:

lead sulfide

DISSOLVE:

filter in tetrahydrofuran

SUSPEND:

dust in tetrahydrofuran

VOL-MIN: -MAX:

600 L @ 0.05 mg (Pb)/m 3 1000 L

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:

suspensions of PbS in 2-propanol

RANGE

30 to 2000 µg per sample

SAMPLE STABILITY:

4% degradation in 45 days; protect samples from light

BLANKS:

2 to 10 field blanks per set

BULK SAMPLE:

required; area respirable or settled dust

ACCURACY RANGE STUDIED: BIAS:

12 to 37 µg/m 3 [1] not significant when samples and standards have equivalent particle size

ESTIMATED LOD: 5 µg per sample PRECISION (Sr):

0.081 (40 to 260 µg per sample [1]

ˆ ): 0.103 [1] OVERALL PRECISION (S rT ACCURACY:

ca. ± 22%

APPLICABILITY: The working range is 0.06 to 4 mg/m 3 for a 500-L air sample. The method is specific for lead sulfide among other mine dusts.

INTERFERENCES: Lead oxide (PbO, Pb 3O 4), lead sulfate (anglesite), copper iron sulfide (chalcopyrite); also see APPENDIX.

OTHER METHODS: This method was originally designated P&CAM 350, which it replaces [2].

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