This method is intended for the semi quantitative (i.e., +/- 25% (See par. 10.1. The precision statement has not been determined by formal round robin.)) determination of ethyl mercaptan odourant (within the range of 5 to 85 mg/L) in liquid propane. It is important to confirm that recently stenched propane is odourized to the required level. The method is intended for field application and may be suitable for use by non laboratory personnel after suitable training. A gas chromatographic method should be used for more precise, quantitative determination of ethyl mercaptan in propane.

Other low molecular weight mercaptans, such as methyl mercaptan, can interfere by giving a positive result.

High concentrations of propylene may interfere, turning the detector (stain) tube grey. Thus this field method, using Gastec tube #72, may not be suitable for some (commercial) propane containing significant levels of propylene.

The testing and evaluation of a product against this method may require the use of materials and/or equipment that could be hazardous. This document does not purport to address all the safety aspects associated with its use. Anyone using this method has the responsibility to consult the appropriate authorities and to establish appropriate health and safety practices in conjunction with any applicable regulatory requirements prior to its use.