METHYLAL
CH3OCH2OCH3
MW: 76.10
METHOD: 1611, Issue 2
1611
CAS: 109-87-5
RTECS: PA8750000
EVALUATION: FULL
OSHA : 1000 ppm NIOSH: 1000 ppm ACGIH: 1000 ppm (1 ppm = 3.11 mg/m 3 @ NTP)
PROPERTIES:
Issue 1: 15 May 1985 Issue 2: 15 August 1994
liquid; d 0.8593 g/mL @ 20 °C; BP 42 °C; MP -105 °C; VP 44 kPa (330 mm Hg; 43% v/v) @ 20 °C; explosive range 1.6 to 17.6% v/v in air
SYNONYMS: dimethoxymethane; formal; formaldehyde dimethyl acetal
SAMPLING SAMPLER:
SOLID SORBENT TUBE (coconut shell charcoal, 100 mg/50 mg)
FLOW RATE:
0.01 to 0.2 L/min
VOL-MIN: -MAX:
1 L @ 1000 ppm 3L
SHIPMENT:
routine
SAMPLE STABILITY:
unknown
FIELD BLANKS:
2 to 10 field blanks per set
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
methylal
DESORPTION:
1 mL hexane; stand 30 min
INJECTION VOLUME:
5 µL
TEMPERATURE-INJECTION: -DETECTOR: -COLUMN: CARRIER GAS:
N 2, 30 mL/min
COLUMN:
stainless steel, 1.2 m x 6-mm OD, packed with 50/80 mesh Porapak Q or equivalent
CALIBRATION:
standard solutions of methylal in hexane
RANGE:
3 to 12 mg per sample
ACCURACY RANGE STUDIED:
1684 to 6670 mg/m 3 [1] (2-L samples)
BIAS:
+ 4.8%
190 °C 250 °C 195 °C
ˆ ): 0.060 [1] OVERALL PRECISION (S rT ACCURACY:
± 15.1%
ESTIMATED LOD: 0.1 mg per sample PRECISION (Sr):
0.017 [1]
APPLICABILITY: The working range is 480 to 1930 ppm (1500 to 6000 mg/m 3) for a 2-L air sample. Samples containing smaller quantities of methylal may have low desorption efficiency. Breakthrough capacity at high humidity is not known.
INTERFERENCES: None identified.
OTHER METHODS: This revises Method S71 [2].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
