Page:NIOSH Manual of Analytical Methods - 7027.pdf/1

 COBALT and compounds, as Co

Co

MW: 58.93 (Co)

METHOD: 7027, Issue 2

7027

CAS: 7440-48-4 (Co) EVALUATION: FULL

OSHA : 0.1 mg/m3 NIOSH: 0.05 mg/m3 ACGIH: 0.05 mg/m3 (fume, dust)

RTECS: GF8750000 Issue 1: 15 February 1984 Issue 2: 15 August 1994

PROPERTIES:

magnetic, hard metal; valence +2, +3; MP 1495 C; VP not significant

SYNONYMS: vary depending upon the compound

SAMPLING SAMPLER:

FLOW RATE: VOL-MIN: -MAX:

MEASUREMENT

FILTER (0.8-µm cellulose ester membrane)

TECHNIQUE:

ATOMIC ABSORPTION, FLAME

1 to 3 L/min

ANALYTE:

cobalt

30 L @ 0.1 mg/m3 1500 L

SHIPMENT:

ASHING:

aqua regia, 3 mL, 140 C;conc. HNO3, 6 mL, 140 C; room temperature, 30 min; 140 C to near dryness

routine FINAL SOLUTION: 5% HNO3, 10 mL

SAMPLE STABILITY:

stable

FLAME:

air-acetylene, oxidizing

FIELD BLANKS:

2 to 10 field blanks per set

WAVELENGTH:

240.7 nm

BACKGROUND CORRECTION: D2 or H2 lamp ACCURACY RANGE STUDIED:

0.03 to 0.26 mg/m [1] (270-L samples)

BIAS:

5.6%

OVERALL PRECISION (

ACCURACY:

CALIBRATION:

Co2+ in 5% HNO3

RANGE:

3 to 90 µg per sample [2]

ESTIMATED LOD:

0.6 µg per sample [3]

PRECISION ( r):

0.03 [1]; 0.02 [3]

3

rT

):

0.070 [1]

± 18.0%

APPLICABILITY: The working range is 0.01 to 0.3 mg/m3 for a 300-L sample. This is an elemental analysis, not compound specific. Verify that the types of compounds in the samples are soluble with this ashing procedure. Aliquots of the samples can be analyzed separately for approximately four additional metals.

INTERFERENCES: The use of D2 or H2 continuum background correction is required to control molecular or flame absorption. There are no known spectral line interferences.

OTHER METHODS: This method combines and replaces P&CAM 173 [4] and S203 [2] for cobalt. Method 7300 (Elements by ICP-AES) is an alternate analytical technique.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition