FORMALDEHYDE by GC
H2C=0
MW: 30.03
METHOD: 2541, Issue 2
CAS: 50-00-0
2541
RTECS: LP8925000
EVALUATION: PARTIAL
OSHA : 0.75 ppm; 2 ppm STEL NIOSH: 0.016 ppm; C 0.1 ppm; carcinogen ACGIH: C 0.3 ppm; suspected human carcinogen (1 ppm = 1.23 mg/m 3 @ NTP)
PROPERTIES:
Issue 1: 15 May 1989 Issue 2: 15 August 1994
gas; vapor density 1.067 (air = 1); BP 19.5 °C; explosive range 7 to 73% v/v in air
SYNONYMS: methanal; formalin (aqueous 30 to 60% w/v HCHO); methylene oxide
SAMPLING SAMPLER:
MEASUREMENT
SOLID SORBENT TUBE (10% (2-hydroxymethyl)piperdine on XAD-2, 120 mg/60 mg
TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
oxazolidine derivative of formaldehyde
FLOW RATE:
0.01 to 0.10 L/min
DESORPTION:
1 mL toluene; 60 min ultrasonic
VOL-MIN: -MAX:
1 @ 3 ppm 36 L
INJECTION VOLUME:
1 µL splitless; split vent time 30 sec
SHIPMENT:
routine
SAMPLE STABILITY:
3 weeks @ 25 °C [1]
TEMPERATURE-INJECTOR: -DETECTOR: -COLUMN:
FIELD BLANKS:
2 to 10 field blanks per set
MEDIA BLANKS:
10 per sample set
ACCURACY RANGE STUDIED:
not determined
BIAS:
not determined
ˆ ): not determined OVERALL PRECISION (S rT ACCURACY:
not determined
250 °C 300 °C 70 °C for 1 min; 15 °C/min; hold @ 240 °C for 10 min
CARRIER GAS:
He, 1 to 2 mL/min: makeup flow 29 mL/min
COLUMN:
capillary, 30 m x 0.32-mm ID, 0.5-µm film, DB-Wax or equivalent
CALIBRATION:
formalin solution spiked on sorbent
RANGE:
3 to 200 µg per sample [2,3]
ESTIMATED LOD: 1 µg per sample [2] PRECISION (Sr):
0.0052 @ 38 to 194 µg per sample [2]
APPLICABILITY: The working range is 0.24 to 16 ppm (0.3 to 20 mg/m 3) for a 10-L air sample. The method is suitable for the simultaneous determinations of acrolein and formaldehyde.
INTERFERENCES: None have been observed. Acid mists may inactivate the sorbent leading to inefficient collection of formaldehyde. A 15 m x 0.32-mm ID DB-1301 fused silica capillary column can also be used. This column will also separate the acetaldehyde and acrolein oxazolidines. A nitrogen-specific detector (NPD) can be used for improved sensitivity.
OTHER METHODS: OSHA Method 52 is similar but uses slightly larger sampling tubes [2]. This method has improved sample stability and ease of personal sampling compared to NIOSH Methods 2502 (which has been withdrawn), 3500 and 3501. However, Method 3500 (chromotropic acid) is the most sensitive.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
