What sampling method is used for methanol vapors?

The correct method for sampling methanol vapors is the use of a silica gel tube that is then analyzed by gas chromatography (GC). This approach is effective because silica gel is capable of adsorbing volatile organic compounds, including methanol, from air samples. Once the air sample is collected and the methanol is retained on the silica gel, it can be desorbed and analyzed using gas chromatography, which separates the compounds in the sample, allowing for accurate quantitative and qualitative analysis of methanol.

Other methods listed, such as X-Ray fluorescence analysis, are not suitable for analyzing organic vapors like methanol because they are primarily used for analyzing metal content in materials, not for evaluating gases or volatile compounds. Gas chromatography/mass spectrometry (GC/MS) is a highly sensitive technique that can certainly be utilized to analyze methanol as well, but it is often more complex and costly, typically reserved for detailed analysis after initial screening. Inductively coupled plasma (ICP) is focused on the analysis of metals and not applicable for organic vapors, confirming that silica gel tubes coupled with GC is the most appropriate method for initial sampling and straightforward analysis of methanol vapors.