METHANOL
CH3OH
MW: 32.04
METHOD: 2000, Issue 3
2000
CAS: 67-56-1
RTECS: PC1400000
EVALUATION: FULL
OSHA : 200 ppm NIOSH: 200 ppm (skin); STEL 250 ppm (skin) ACGIH: 200 ppm (skin); STEL 250 ppm (skin) (1 ppm = 1.310 mg/m3 @ NTP)
PROPERTIES:
Issue 1: 15 August 1984 Issue 3: 15 January 1998 liquid; d = 0.792 g/ml @ 20 C; BP = 64.5 C; VP = 15.3 kPa (115 mm Hg; 15.1% v/v) @ 20 C; explosive range is 6 to 36% (v/v) in air
SYNONYMS: Methyl alcohol, wood alcohol, carbinol, wood naphtha, wood spirit
SAMPLING SAMPLER:
SOLID SORBENT TUBE (silica gel, 100/50 mg)
FLOW RATE:
0.02 to 0.2 L/min
VOL-MIN: -MAX:
1 L @ 200 ppm 5L
SHIPMENT:
pack securely for shipment; store at 5 C.
SAMPLE STABILITY :
at least 30 days at 5 C [1]
BLANKS:
2 to 10 field blanks per set
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
methanol
DESORPTION:
1 mL water/isopropanol (95:5) [1]
INJECTION VOLUME:
1 µL
TEMPERATURE- INJECTION: -DETECTOR: -COLUMN:
250 C 300 C 50 to 90 C (8 C/min) [1] (Split Ratio 10:1)
CARRIER GAS:
He, 2.6 mL/min
COLUMN:
capillary, 30 m x 0.53-mm ID; 3-µm film 35% diphenyl-65% dimethyl polysilozane, Rtx™-35 or equivalent [1]
CALIBRATION:
standard solutions of water/isopropanol (95:5)
RANGE:
2.2 to 6000 µg per sample [1,2]
ACCURACY RANGE STUDIED:
140 to 540 mg/m3 [2]
BIAS:
-4.4%
OVERALL PRECISION ( ACCURACY:
rT
): 0.074 [1, 2] ±16.2%
methanol
in
ESTIMATED LOD: 0.7 µg per sample [1] PRECISION ( r):
0.030 [1]
APPLICABILITY: Under the GC parameters stated in the method, methanol may be identified based upon retention time and quantified. The working range is 0.4 to 1200 mg/m3 (0.3 to 916.0 ppm) for a 5-L air sample [1]. At high concentrations of methanol or under conditions of high relative humidity, a large silica gel tube (700 mg) is required [2].
INTERFERENCES: No specific interferences were identified. However, any compound with a similiar retention time may interfere. Positive identification can be confirmed by dual column chromatography with a 100% PEG capillary column. Mass spectrometry can also be used as a confirmation aid.
OTHER METHODS: This method updates and replaces NMAM 2000 (August 15, 1994), which combined and replaced Method S59 [3] and P&CAM 247 [4].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
