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
