Page:NIOSH Manual of Analytical Methods - 2004.pdf/2

 DIMETHYLFORMAMIDE (See Method 2004, DIMETHYLACETAMIDE, for procedure)

O=CHN(CH3)

MW: 73.10

METHOD: 2004, Issue 2

CAS: 68-12-2

RTECS: LQ2100000

EVALUATION: FULL

OSHA : 10 ppm (skin) NIOSH: 10 ppm (skin) ACGIH: 10 ppm (skin) 1 ppm = 2.99 mg/m 3 @ NTP

PROPERTIES:

2004

Issue 1: 15 May 1989 Issue 2: 15 August 1994

liquid; d 0.95 g/mL @ 25 °C; BP 153 °C; MP -61 °C; VP 2.7 mm Hg @ 20 °C; explosive range in air (v/v) 2.2 to 15.2%

SYNONYMS: N-formyldimethylamine; DMF; N,N-dimethylformamide

SAMPLING SAMPLER:

SOLID SORBENT TUBE (silica gel, 150 mg/75 mg)

FLOW RATE:

0.01 to 1 L/min

VOL-MIN: -MAX:

15 L @ 30 mg/m 3 80 L

SHIPMENT:

routine

MEASUREMENT TECHNIQUE:

GAS CHROMATOGRAPHY, FID

ANALYTE:

dimethylformamide

DESORPTION:

1 mL methanol; 1 h in ultrasonic bath

INJECTION VOLUME:

5 µL

SAMPLE STABILITY:

at least 5 days @ 25 °C [1]

TEMPERATURE-INJECTION: -DETECTOR: -COLUMN:

240 °C 320 °C 140 °C

BLANKS:

2 to 10 field blanks per set

CARRIER GAS:

N 2, 50 mL/min

COLUMNS:

1.5 m x 6-mm OD glass; 10% UCON 50-HB-5100, 2% KOH on 100/120 mesh Chromosorb WHP

CALIBRATION:

analyte in methanol

RANGE:

0.5 to 4 mg per sample [1,2]

ACCURACY RANGE STUDIED:

11 to 61 mg/m 3 [1]; (45-L samples)

BIAS:

- 1.1%

ESTIMATED LOD: 0.05 mg per sample [2]

ˆ rT): 0.056 [1] OVERALL PRECISION (S ACCURACY:

± 11.7%

PRECISION (Sr):

0.037 [1]

APPLICABILITY: The working range is 3.3 to 27 ppm (10 to 80 mg/m 3) for a 50-L air sample. The lower limit is determined by the desorption efficiency which must be determined over the range used. Silica gel has a high affinity for water; high r elative humidity may adversely affect the efficiency of analyte adsorption.

INTERFERENCES: None identified. Separation conditions (column, temperature, etc.) may be changed to circumvent problems. Alternate columns include: 60/80 mesh Chromosorb P coated with 20% UCON LB 550X and 2% KOH; 100/120 mesh Chromosorb WHP with 10% Carbowax 20M and 2% KOH; 100/120 mesh Chromosorb WHP with 10% SP-2250; and 30-m x 0.32-mm capillary coated with 0.5 µm DB Wax.

OTHER METHODS: This combines and replace Methods S254 and S255 [2].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94