MERCAPTANS, METHYL-, ETHYL-, and n-BUTYL- 2542
CH3
SH MW: 48.11 CAS: 74-93-1 RTECS: PB4375000
CH3
CH2
SH MW: 62.13 CAS: 75-08-1 RTECS: KI9625000
CH3
CH2
CH2
CH2
SH MW: 90.19 CAS: 109-79-5 RTECS: EK6300000
METHOD: 2542, Issue 1 EVALUATION: PARTIAL Issue 1: 15 August 1994
OSHA: Table 1
NIOSH: Table 1
ACGIH: Table 1
PROPERTIES: Table 1
SYNONYMS: Methyl mercaptan: methanethiol; mercaptomethane; methyl sulfhydrate
Ethyl mercaptan: ethanethiol; mercaptoethane; ethyl sulfhydrate
n-Butyl mercaptan: butanethiol; 1-mercaptobutane; 1-butanethiol
SAMPLING
SAMPLER: FILTER
(glass fiber, 37-mm, impregnated with
mercuric acetate)
FLOW RATE: 0.1 to 0.2 L/min
VOL-MIN: 10 L @ 0.5 ppm
-MAX: 150 L
SHIPMENT: protect samples from light [1,2]
SAMPLE
STABILITY: at least 3 weeks @ 25 °C
BLANKS: 2 to 10 field blanks per set
ACCURACY
RANGE STUDIED: Table 2
BIAS: not determined
OVERALL PRECISION ( ): Table 2
ACCURACY: not determined
MEASUREMENT
TECHNIQUE: GAS CHROMATOGRAPHY, FPD SULFUR
MODE
ANALYTE: methyl, ethyl, and n-butyl mercaptans
EXTRACTION: 20 mL HCl (25% v/v) plus 5 mL 1,2-
dichloroethane, 2 min
INJECTION
VOLUME: 1 µL
TEMPERATURE-INJECTION: 250 °C
-DETECTOR: 250 °C
-COLUMN: 30 °C 2 min, 15 °C/min, 200 °C
COLUMN: narrow-bore, fused-silica capillary, 30 cm
× 0.25-mm ID, 1 µm DB-1
CARRIER GAS: He, 1.0 mL/min; makeup gas: N2
, 20 mL/
min
CALIBRATION: standard solutions of mixed mercaptans
in 1,2-dichloroethane
RANGE: Table 2
ESTIMATED LOD: Table 2
PRECISION ( ): Table 2
APPLICABILITY: The working ranges are 0.2 to 10 ppm for a 20-L air sample for all three mercaptans [1–4].
INTERFERENCES: Dimethyl disulfide, diethyl disulfide, and dibutyl disulfide may interfere [2–4].
OTHER METHODS: This is a modification of OSHA Method 26 for methyl mercaptan with the addition of ethyl- and n-butyl
mercaptan [2].