On August 11th, 2011 the herbicide Aminocyclopyrachlor, licensed by Dupont as Imprelis, was banned from sale, use and distribution by the EPA. One week prior to the announcement Dupont voluntarily began a recall program after numerous reports of tree losses following application of the herbicide. Registered on September 2nd, 2010 the product was on the market for less than a year before significant damage to spruce and pine trees had occurred. The majority of the early applications were done professionally on commercial properties; however, residential sale was planned for later this year under the trade name MAT28.
Imprelis is considered a synthetic auxin and while auxins are critical to plant metabolism, high concentrations produces excess ethylene and inhibits growth. The most commonly used auxin for weed control is 2,4-D (2,4-dichlorophenoxy acid). Dupont and EPA warn not to use grass clippings from treated areas for mulching or compost. Grass clippings must be left in place or disposed of in the trash.
Current EPA methods that may work for analyzing this compound are EPA 8151A in a waste situation or EPA 515.4 Rev 1.0 (2000) for drinking water. Both methods involve derivitization prior to GC/ECD analysis. We recommend using the Rtx-CLpesticides and Rtx-CLPesticides2 for these dual column methods. Let us know if you have analyzed Imprelis or need assistance.
Special thanks to Al Sensue, Sr. Technical Service Representitive, for his contributions to this article.
Notes: Aminocyclopyrachlor cas#858956-08-8. The esterified compound, aminocyclopyrachlor-methyl cas# 858954-83-3.
This PSU website has some great pictures: