Page:NIOSH Manual of Analytical Methods - 2016.pdf/1

 FORMALDEHYDE H2 C=O METHOD:

OSHA : NIOSH: ACGIH:

MW:

30.03

2016, Issue 2

CAS: 50-00-0 EVALUATION: FULL

0.75 ppm; 2 ppm STEL 0.016 ppm; C 0.1 ppm; carcinogen C 0.3 ppm; suspected human carcinogen (1 ppm = 1.23 mg/m3 @ NTP)

PROPERTIES:

2016 RTECS: LP8925000 Issue 1: 15 January 1998 Issue 2: 15 March 2003

Gas; BP -19.5 o C; specific gravity 1.067 (air = 1); explosive range 7 to 73% (v/v) in air

NAMES & SYNONYMS: methanal; formalin (aqueous 30 to 60% w/v formaldehyde); methylene oxide

SAMPLING SAMPLER:

CARTRIDGE (Cartridge containing silica gel coated with 2,4-dinitrophenylhydrazine)

MEASUREMENT TECHNIQUE:

HPLC, UV DETECTION

ANALYTE:

2,4-dinitrophenylhydrazone of formaldehyde

EXTRACTION:

Elution with 10 mL of carbonyl-free acetonitrile

FLOW RATE: 0.03 to 1.5 L/min VOL-MIN: -MAX:

1 L @ 0.25 mg/m3 15 L @ 2.5 mg/m3

SHIPMENT:

Place caps onto cartridge. Ship on ice.

SAMPLE STABILITY:

34 days @ 5 °C [1]

BLANKS:

2 to 10 field blanks per set 6 to 10 media blanks per set

ACCURACY RANGE STUDIED:

0.025 to 2.45 mg/m3 (22-L samples) [2]

BIAS:

+4.4%

OVERALL PRECISION ( Ö r T ):

0.057 [1,2]

ACCURACY:

±19.0%

INJECTION VOLUME:

20 µL

MOBILE PHASE:

45% acetonitrile/55% water (v/v), 1.3 mL/min

COLUMN:

3.9 x 150-mm, stainless steel, packed with 5-µm C-18, SymmetryT M or equivalent

DETECTOR:

UV @ 360 nm

CALIBRATION:

Samplers fortified with standard solutions of formaldehyde in water

RANGE:

0.23 to 37 µg per sample [1,2]

ESTIMATED LOD: 0.07 µg/sample [1] PRECISION ( þ r ):

0.032 @ 1.0 to 20.0 µg/sample [1]

APPLICABILITY: The working range is 0.015 to 2.5 mg/m3 (0.012 to 2.0 ppm) for a 15-L sample. This method can be used for the determination of formaldehyde for both STEL and TWA exposures [1,2]. INTERFERENCES: Ozone has been observed to consume the 2,4-dinitrophenylhydrazine (2,4-DNPH) reagent and to degrade the formaldehyde derivative [3]. Ketones and other aldehydes can react with 2,4-DNPH; the derivatives produced, however, are separated chromatographically from the formaldehyde derivative. OTHER METHODS: NIOSH methods 2541 [4] and 3500 [5] and OSHA method 52 [6] are other methods for determination of formaldehyde in air. NIOSH method 5700 employs 2,4-DNPH and HPLC for determination of formaldehyde on textile or wood dust [7]. A journal method employs the same procedure for formaldehyde in automobile exhaust [8].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition