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
