Page:NIOSH Manual of Analytical Methods - 1611.pdf/1

 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