National Institute for Occupational Safety and Health

“ The potential interferences include other organic compounds, in particular other pesticides or fungicides that have the same retention time on a C18 column. Positive identification may be confirmed by dual column chromatography using an appropriate alternative LC column. Possible interferences include: ziram, myclobutanil, mancozeb, imidacloprid, and phosmet. OTHER METHODS: This method was developed in conjunction with method NMAM 5606, Thiophanate-methyl in air, and NMAM 9202, Captan and Thiophanate-methyl in handrnise. ”

“ The storage study at 4°C was completed at 6000 μg/sample for thiophanate-methyl, and 1500 μg /sam ple for captan with respective recovery averages of 8 6.2 -92.2 %, and 87.6 -95.7 % over the 28 days of the study. Carbendazim , which is a decomposition product of thiophanate-methyl, may also be found in the chromatogram along with the other two a nalytes. ”

“ NOTE: If peak area of a sample is greater than the area of the highest standard, dilute with extracting solvent and reanalyze. 13. Measure peak area of the analyte.
CALCULATIONS: 14. Perform a separate regre ssion analysis of the peak area s vs. quantity of standard for each of the two analytes. De term ine the concentration ,μg /m L, (correcte d fo r DE) of the analyte in each sam ple patch (C P) and in the m edia blank (B b) from the calibration graph. 15. Ca lculate the mass of each analyte, M (:g) , on a sample patch by adjusting for the volume , V (mL) of extra ction s olven t. ”