Page:NIOSH Manual of Analytical Methods - 7502.pdf/1

 ZINC OXIDE

ZnO

MW: 81.38

METHOD: 7502, Issue 2

CAS: 1314-13-2 EVALUATION: FULL

OSHA : 5 mg/m 3 (fume); 15 mg/m 3 (dust) NIOSH: 5 mg/m 3; C 15 mg/m 3/15 min (dust); 5 mg/m 3; STEL 10 mg/m 3 (fume) ACGIH: 5 mg/m 3; STEL 10 mg/m 3 (fume) 10 mg/m 3 (dust)

7502

RTECS: ZH4810000 Issue 1: 15 February 1984 Issue 2: 15 August 1994

PROPERTIES: solid; d 5.61 g/cm 3 @ 25 °C; MP 1975 °C

SYNONYMS: China white; zinc white; zincite.

SAMPLING SAMPLER:

FILTER (0.8-µm PVC membrane, 25-mm diameter, in open-face cassette)

MEASUREMENT TECHNIQUE:

X-RAY POWDER DIFFRACTION

ANALYTE:

crystalline zinc oxide; direct analysis on filter

XRD:

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

CALIBRATION:

suspensions of ZnO in 2-propanol

RANGE:

50 to 2000 µg per sample

FLOW RATE: 1 to 3 L/min VOL-MIN: -MAX:

10 L 400 L

SHIPMENT:

routine

SAMPLE STABILITY:

stable

BLANKS:

2 to 10 field blanks per set ESTIMATED LOD: 5 µg per sample

BULK SAMPLE:

high-volume air sample required

PRECISION (Sr):

0.15 @ 1 mg/m 3; 0.05 for greater than 2 mg/m 3

ACCURACY RANGE STUDIED:

0.1 to 11 mg/m 3 [1,2] (180-L samples)

BIAS:

2.7% [2,3,4]

ˆ ): 0.09 [2] OVERALL PRECISION (S rT ACCURACY:

± 21.6%

APPLICABILITY: The working range is 0.25 to 10 mg/m 3 for a 200-L air sample. The method does not distinguish zinc oxide fume from zinc oxide dust.

INTERFERENCES: Major interferences include Fe 2O 3, Zn, Zn(NH 3)2Cl2, (NH 4)3ZnCl 5, (NH 4)2ZnCl 4 and (NH 4)2Zn(SO 4)2 6H 2O; these are resolved by using alternate analyte peaks. Particle size affects intensity measurements.

OTHER METHODS: This method combines and replaces Methods P&CAM 222 [1] and S316 [5]. The criteria document contains an elemental analysis for zinc [6].

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