Page:NIOSH Manual of Analytical Methods - 7048.pdf/1

 CADMIUM and compounds, as Cd

Cd

MW: 112.40 (Cd); 128.40 (CdO)

CAS: 7440-43-9 (Cd); 1306-19-0 (CdO)

METHOD: 7048, Issue 2

RTECS:

EVALUATION: FULL

OSHA : 0.1 mg/m 3, C 0.3 (fume); 0.2, C 0.6 (dust) NIOSH: lowest feasible; carcinogen ACGIH: 0.01 mg/m 3 (total dust); 0.002 mg/m 3 (respirable); carcinogen

PROPERTIES:

7048

EU9800000 (Cd) EV1930000 (CdO)

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

soft metal; valence +2; BP 765 °C; MP 320.9 °C

SYNONYMS: Vary depending upon the compound.

SAMPLING

MEASUREMENT

SAMPLER:

FILTER (0.8-µm cellulose ester membrane)

FLOW RATE:

1 to 3 L/min

VOL-MIN: -MAX:

25 L @ 0.1 mg/m 3 1500 L

SHIPMENT:

routine

SAMPLE STABILITY:

stable

BLANKS:

2 to 10 field blanks per set

TECHNIQUE:

ATOMIC ABSORPTION, FLAME

ANALYTE:

cadmium

ASHING:

conc. HNO 3, 6 mL; 140 °C conc. HCl, 6 mL; 400 °C

FINAL SOLUTION:

0.5 N HCl; 25 mL

FLAME:

air-acetylene, oxidizing

WAVELENGTH:

228.8 nm

BACKGROUND CORRECTION: D 2 or H 2 continuum

ACCURACY

CALIBRATION:

Standard solutions of Cd in 0.5 N HCl

RANGE:

2.5 to 30 µg per sample

RANGE STUDIED:

0.12 to 0.98 mg/m 3 [1] (25-L samples)

ESTIMATED LOD: 0.05 µg per sample [2]

BIAS:

- 1.57%

PRECISION (Sr):

ˆ ): OVERALL PRECISION (S rT

0.06 [1]

ACCURACY:

± 13.23%

0.05 @ 3 to 23 µg per sample [1,3,4]

APPLICABILITY: The working range is 0.1 to 2 mg/m 3 for a 25-L air sample, and 0.01 to 0.2 mg/m 3 for a 250-L air sample. This is an elemental analysis and it will not distinguish Cd fume from Cd dust. Aliquots of the ashed samples can be analyzed separately for many additional metals.

INTERFERENCES: Background correction is required to control molecular or flame absorption. Iron does not interfere at 20 parts Fe to 1 part Cd [1].

OTHER METHODS: This method combines and replaces P&CAM 173 [5], S312 [4], and S313 [6]. A similar method appears in the criteria document [7]. Method 7300 (ICP-AES) is an alternate, multielement measurement method with approximately the same sensitivity. Aliquots of the ashed samples can be analyzed by graphite furnace atomic absorption with greatly incre ased sensitivity.

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