Significance and Use
Mercaptans are odorous substances offensive at low concentrations and toxic at higher levels. They are emitted from geothermal sources, industrial processes, and food processing facilities.
1.1 This test method covers measurement of the concentration of mercaptans (organic thiols) in the atmosphere at concentrations below 100 parts per billion (ppb(v) = 195 μg/m3). For concentrations above 100 ppb(v) level, the sampling period can be reduced or the liquid volume increased either before or after aspirating. The minimum detectable amount of methyl mercaptan is 0.04 μg/mL (1) in a final liquid volume of 25 mL. When sampling air at the maximum recommended rate of 2 L/min for 2 h, the minimum detectable mercaptan concentration is 1.0 ppb(v) (1.95 μg methyl mercaptan/m3 at 101.3 kPa (760 mm Hg) and 25°C). This test method determines total mercaptans and does not differentiate among individual mercaptans, although it is most sensitive to the lower molecular weight alkanethiols.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in 8.7, 8.8, and Section 9.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1193 Specification for Reagent Water
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D1357 Practice for Planning the Sampling of the Ambient Atmosphere
D1914 Practice for Conversion Units and Factors Relating to Sampling and Analysis of Atmospheres
D2914 Test Methods for Sulfur Dioxide Content of the Atmosphere (West-Gaeke Method)
D3195 Practice for Rotameter Calibration
D3249 Practice for General Ambient Air Analyzer Procedures
D3609 Practice for Calibration Techniques Using Permeation Tubes
D3631 Test Methods for Measuring Surface Atmospheric Pressure
E1 Specification for ASTM Liquid-in-Glass Thermometers
ambient atmospheres; analysis; mercaptans; sampling;
ICS Number Code 13.040.20 (Ambient atmospheres)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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