Endosulfan Pesticide Concentration Analysis with Gas Chromatography

Jessica V. Gonzalez, Undergraduate SRAI Researcher
Kevin O'Shea, instructor

The Agriculture Industry widespread use of pesticides can lead to contamination of soils, may enter water sources, and pose an environmental and human health threat. Endosulfan is an efficient, manufactured, and commonly used pesticide in many areas of the world. It is a pesticide used to control pest infestations on both food and nonfood crops. The structure of endosulfan is a chlorinated cyclic sulfite diester, an organochlorine which is persistent in the environment for extended time periods. However, coupled with endosulfan's effective pest control are the hazards of a neurotoxin. Because endosulfan possesses strong neuron toxicity and persists in the environment it is critical to identify effective methods to detect, analyze, and remediate endosulfan.

In South Florida's Miami-Dade County, endosulfan is used excessively. An experiment is conducted using a vegetable buffer strip with a top layer of the soil containing fungi and bacteria to reduce endosulfan runoff in Miami-Dade's soil. The degradation of endosulfan is monitored using Gas Chromatography- Electron Capture Detector (GC-ECD).A 1 L sample is injected and carried by helium gas through the GC in splitless mode. The sample travels through a DB-5 column and the different compounds are separated to yield unique retention times based on their affinity towards the column. The ECD detects electron-absorbing components in vapor phase. The analyte concentration is proportional to the level of electron captured, and the concentration of endosulfan can be determined by using a calibration curve of the internal standard pentacholoronitrobenzene (PCNB). The projected research is to analyze the unknown concentration of field samples using the PCNB internal standard calibration curve in order to evaluate the efficiency of a vegetable buffer strip containing fungi and bacteria in Miami-Dade's soil in reducing endosulfan runoff.

This project has been made possible by funding support under the USDA CSREES HSI
Higher Education Grant Program. USDA-CSREES Grant Number 2005-36422-15940.