Yongkang Wen

Document Type

Thesis - University Access Only

Award Date

1994

Degree Name

Master of Science (MS)

Department / School

Chemistry

First Advisor

Duane Matthees

Abstract

An analytical method using capillary gas chromatography and mass spectrometry (GC/MS) with selected ion monitoring (SIM) to determine thirteen common herbicide residues( clopyralid, dicamba, MCPA, bromoxynil, 2,4-D, triclopyr, bentazon, DCPA, fluazifop, picloram, acifluorfen, diclofop, fenoxaprop) has been developed. The method involves an alkaline hydrolysis for extracting herbicides from the plant tissue, solvent partitioning into methylene chloride, followed by methylation of the extracted acidic herbicides with diazomethane. Florisil column cleanup was used for the removal of interfering coextractants. Separation and quantification of the herbicides was carried out by capillary GC/MS with SIM. The objective of this research was the development of a simple and efficient method for quantitative multiclass and multiresidue herbicide analysis in plants. An improved Florisil cleanup procedure was developed for removal of many interferences from 13 herbicides that have different structural and polarity properties. The recoveries of residues at the 1 ppm level were 80%-- 95% and at the 0.1 ppm level were 75% --85%. Detection limits were on the range of 0.2 to 0.02 ng depending on the herbicide. This corresponds to about 0.1 ppm to 0.01 ppm in the sample.

Library of Congress Subject Headings

Herbicides
Gas chromatography
Mass spectrometry

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright