Fumigants are pesticides in the form of gases that are slightly heavier than air and have the ability to spread to all areas and surfaces. Highly volatile fumigants are used to sterilize soil before planting crops such as strawberries, potatoes and carrots. Some of the most widely used fumigants include methyl bromide (MeBr), methyl iodide (MeI) and chloropicrin, which are among the most toxic chemicals used in agriculture. The U.S. EPA categorizes them as 'highly acutely toxic', which is the agency's highest toxicity category. Current quantitative measurement of fumigants can take days and be quite costly. Thus, rapid, onsite, economic, and accurate detection and indication of exposure and concentrations of fumigants is necessary for human safety and protection of farm workers. In this presentation, preparation of novel ultra-sensitive sensors for naked-eye colorimetric detection of MeI, MeBr and chloropicrin will be discussed. The prepared sensors have detection limits as low as 200 ppb for MeI, 800 ppb for MeBr and 2 ppb for chloropicrin by naked eye. The detection limits found in this study are noticeably lower than the Permissible Exposure Limit (PEL) for MeBr, MeI and chloropicrin which are 20 ppm, 2 ppm and 200 ppb respectively. By using these colorimetric sensors farm workers can easily, instantly and onsite detect the amount of the fumigants exposed in the air and prepare for proper personal protection. Some of the sensors can be possibly used as attached strips on clothing or testing strips by farm workers.

Development of fast and highly sensitive colorimetric sensors for methyl iodide, methyl bromide, and chloropicrin

248th National Meeting (2014)

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