Page:NIOSH Manual of Analytical Methods - 1001.pdf/1

 METHYL CHLORIDE

CH3Cl

MW: 50.49

METHOD: 1001, Issue 2

CAS: 74-87-3

1001

RTECS: PA6300000

EVALUATION: FULL

OSHA : 100 ppm; C 200 ppm; P 300 ppm NIOSH: lowest feasible; carcinogen ACGIH: 50 ppm; STEL 100 ppm (skin) (1 ppm = 2.06 mg/m 3 @ NTP)

Issue 1: 15 August 1987 Issue 2: 15 August 1994

PROPERTIES: gas; vapor density 1.8 (air = 1); BP -24.2 °C; MP -97.7 °C; explosive range 7.6 to 19% v/v air

SYNONYMS: chloromethane.

SAMPLING SAMPLER:

SOLID SORBENT TUBES (two coconut shell charcoal tubes in series, 400 mg/200 mg and 100 mg/50 mg)

MEASUREMENT TECHNIQUE:

GAS CHROMATOGRAPHY, FID

ANALYTE:

methyl chloride

FLOW RATE: 0.01 to 0.1 L/min

DESORPTION:

3 mL CH 2Cl2

VOL-MIN: -MAX:

0.4 L @ 100 ppm 3L

INJECTION VOLUME:

5 µL

SHIPMENT:

refrigerated

SAMPLE STABILITY:

TEMPERATURE-INJECTOR: -DETECTOR: -COLUMN:

95% recovery after 7 days @ 25 °C [1]

BLANKS:

2 to 10 field blanks per set

ACCURACY RANGE STUDIED: 110 to 460 mg/m 3 (1.5-L air samples); 300 to 1200 mg/m 3 (0.5-L air samples) [1] BIAS:

1.04%

200 °C 260 °C 100 °C

CARRIER GAS:

N 2, 30 mL/min

COLUMN:

stainless steel, 1.2 m x 6-mm OD, packed with 80/100 mesh Chromosorb 102

CALIBRATION:

standard solutions of methyl chloride in CH 2Cl2

RANGE:

0.1 to 1 mg per sample

ESTIMATED LOD: 0.01 mg per sample [2]

ˆ ): 0.052 [1] OVERALL PRECISION (S rT ACCURACY:

± 12.41%

PRECISION (Sr):

0.017 @ 0.16 to 0.62 mg per sample [1]

APPLICABILITY: The working range is 31 to 320 ppm (66 to 670 mg/m 3) for a 1.5-L air sample. The method is applicable to STEL determinations.

INTERFERENCES: None reported. An alternate GC column is fused silica capillary, 30 m x 0.315-mm, coated with 0.25-µm Durawax DX-4 at 45 °C [2].

OTHER METHODS: This combines and revises Methods S99 [3] and P&CAM 201 [4].

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