PH06 Agrochemicals, Pesticides, Pharmaceuticals
Exhibit Hall
8:00 AM - Thursday
(PH058) An improved analytical method for the determination of unstable and volatile organophosphorous pesticides in complex environmental matrices.
Cejas, Mark1, 2, 3, Fernandez, Adolfo2, 3, Gardinali, Piero 1, 2, 1 Florida International University, Department of Chemistry & Biochemsitry, Miami, Florida, USA2 Florida International University, Southeast Environmental Research Center, Miami, Florida, USA3 Florida International University, Department of Environmental Studies, Miami, Florida, USA
ABSTRACT- Organophosphorous (OP) pesticides are perhaps the most widely used insecticides since the ban of organochlorine pestides. They are a powerful suite of cholinesterase inhibiting compounds that are known to be non persistent in environmental samples. Many chemical methods have been developed focusing specifically on select compounds like chloropyrifos and parathion that share common chemical properties often neglecting others that are more labile but equally important. One of the biggest challenges on analyzing OPs is their wide variety in physical and chemical properties such as stability, polarity and water solubility thus, very few comprehensive analytical methodologies have been successfully developed that produce good analytical performance over a large number of compounds. A practical method was developed and optimized for the determination of 38 OP residues in organic rich soils and fish collected from the Florida Everglades. The analytical precision and accuracy was evaluated for the complex matrices in terms of the MDLs and compound recoveries at low levels. The method employs a combination of accelerated solvent extraction (ASE) combined with silica and gel permeation chromatography (GPC) and gas chromatography-mass spectrometry detection (GC/MS). Typical method detection limits range from 0.02 to 16.1 ng/g for soils and slightly higher for fish. 35 analytes are recovered above 60 % with an overall average of 83% in both matrices. Only 3 of 38 OPs are lost in the method mainly because of volatilization during sample processing.
Key words: organic rich soil, organophsophorous pesticides, fish tissue, Florida Everglades