CALCIUM and compounds, as Ca
Ca
MW: Table 1
METHOD: 7020, Issue 2
CAS: Table 1
7020
RTECS: Table 1
EVALUATION: FULL
OSHA : Table 1 NIOSH: Table 1 ACGIH: Table 1
PROPERTIES:
Issue 1: 15 February 1984 Issue 2: 15 August 1994
soft, reactive metal; valence 2; MP 848 °C; VP not significant
SYNONYMS: Quicklime (CaO); limestone (CaCO 3 ); marble (CaCO 3 ); hydrated lime (Ca(OH) 2 )
SAMPLING
MEASUREMENT
SAMPLER:
FILTER (0.8-µm cellulose ester membrane)
FLOW RATE:
1 to 3 L/min
VOL-MIN: -MAX:
20 L @ 5 mg/m 3 400 L
SHIPMENT:
routine
FINAL SOLUTION:
SAMPLE STABILITY:
stable
FLAME:
air-acetylene, reducing
BLANKS:
2 to 10 field blanks per set
WAVELENGTH:
422.7 nm
BACKGROUND CORRECTION:
none used
CALIBRATION:
Ca 2+ in 5% HCl
RANGE:
0.08 to 1.7 mg per sample [2]
ESTIMATED LOD:
0.001 mg per sample [3]
PRECISION (Sr):
0.02 [1,3]
ACCURACY RANGE STUDIED:
2.6 to 10.2 mg/m 3 [1] (85-L samples)
BIAS:
- 0.39%
ˆ ): 0.063 [1] OVERALL PRECISION (S rT ACCURACY:
TECHNIQUE:
ATOMIC ABSORPTION, FLAME
ANALYTE:
calcium
ASHING:
conc. HNO 3 , 6 mL; 140 °C 60% (w/v) HClO 4 , 2 mL; 400 °C
5% HCl; 100 mL 1000 µg/mL Cs; 1000 µg/mL La
± 11.5%
APPLICABILITY: The working range is 1 to 20 mg/m 3 for an 85-L air sample. This is an elemental analysis, not compound specific. Verify that the compounds in the samples are soluble with the ashing procedure. Aliquots of the samples can be analyzed separately for many additional metals.
INTERFERENCES: The use of 1000 µg/mL Cs controls ionization in the flame caused by metals such as Na, K, Li, and Mg. The presence of Si, Al, or H 3 PO 4 require the use of 1% (w/w) La as a releasing agent.
OTHER METHODS: This method combines and replaces P&CAM 173 [4] and S205 [2]. Method 7300 (ICP-AES) is an alternate analytical method.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
