Page:NIOSH Manual of Analytical Methods - 2004.pdf/1

 DIMETHYLACETAMIDE

CH3CON(CH3)2

MW: 87.12

METHOD: 2004, Issue 2

CAS: 127-19-5

2004

RTECS: AB7700000

EVALUATION: FULL

OSHA : 10 ppm (skin) NIOSH: 10 ppm (skin) ACGIH: 10 ppm (skin) (1 ppm = 3.56 mg/m 3 @ NTP)

PROPERTIES:

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

liquid; BP 164.5 - 166 °C; MP -20 °C; d 0.937 g/mL @ 25 ° C; VP 1.5 mm Hg @ 20 °C; flash point 70 °C, explosive range 1.8 to 11.5%

SYNONYMS: N,N-dimethylacetamide; acetyldimethylamine; DMAC

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:

dimethylacetamide

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: BIAS:

18 to 105 mg/m 3 [1]; (45-L samples) - 0.8%

ESTIMATED LOD: 0.05 mg per sample [2]

ˆ ): 0.067 [1] OVERALL PRECISION (S rT ACCURACY:

± 11.7%

PRECISION (Sr):

0.032 [1]

APPLICABILITY: The working range is 10 to 80 mg/m 3 of dimethylacetamide or dimethyformamdide 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 hi gh affinity for water; high relative 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 column 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