Chromatography: The Key To Quantifying Herbicide Dissipation
K. M. Eason*, T. L. Grey
The University of Georgia, Dept. of Crop and Soil Sciences, Tifton, GA 31794
Chromatography was named for the colorful bands of leaf pigment that separated after being passed through a column with gravity supplied solvent. Today, chromatography includes the combination of high pressure, various column types, and a wide spectrum of detectors. High performance liquid chromatography (HPLC) is now one of the most powerful tools in analytical chemistry, having the ability to separate, identify, and quantitate various compounds present in a wide range of sample types. This research focused on using chromatography to quantitate the persistence of a residual herbicide in soil. Indaziflam, a commonly used pecan herbicide, was applied to the soil in pecan groves. Soil was sampled from 2016 to 2018 in two different locations, and frozen until analysis. Indaziflam was then extracted from the soil and, using chromatography coupled with mass spectrometry, analyzed for the specific concentration at each day after application. From the HPLC system, a part per billion is quantified for each sample date. The data shows indaziflam being present in the soil for both locations 500 days after one single application.
When planting permanent crops, such as pecans, growers can know exactly how long various herbicides remain in the soil and use this information when making crucial replanting decisions. In both pecan groves, chromatography was the key to understanding herbicide persistence and dissipation.