There is currently no published method for the analysis of the herbicide quizalofop-p-tefuryl or its matabolite quizalofop in biological matrices. Quizalofp-p-tefuryl is a relatively new herbicide with apparent low toxicity and is readily degraded. Its metabolite also has herbicide activity. Quizalofop-p-tefuryl is a aryloxyphenoxypropionate and is a post emergence herbicide used for pulses and vegetables. This work reports on a method for the analyses of this pesticide residue and its metabolite in soybean using HPLC on a C-18 column with UV detection at 332 nm. Several methods are tried including some involving the use of solid phase extractors like silica, Florisil and strong cationic exchange cartridges. The main method developed uses an extraction solvent hexane: acetone: acetic acid for extracting the quizalofop-p-tefuryl and quizalofop from the ground soybean. The extracts are then made alkaline with NaOH and this deprotonates the quizalofop separating it from the hexane phase which contains the quizalofop-p-tefuryl. The hexane phase is extracted with ACN and quizalofop-p-tefuryl partitions into this phase. The quizalof-p-tefuryl is repartitioned into a fresh diethyl ether: hexane phase by adding a large quantity of H2O and NaCL to the ACN layer. The organic phase is washed and evaporated to dryness before being made up to volume with ACN for direct analysis by UV detection or by derivatising it to methoxychloroquinoxaline for fluorescence detection. Using the method that directly detects the analytes, for quizalofop-p-tefuryl and quizalofop at spike levels, the method has average recoveries. The precision of recoveries for both compounds is about 9%. The method is fairly robust. Time of analysis per analyte is about 2 hrs. / Master of Science
| Identifer | oai:union.ndltd.org:ADTP/235469 |
| Date | January 2000 |
| Creators | He, Peter Yunfeng, University of Western Sydney, Faculty of Informatics, Science and Technology, School of Science, Food and Horticulture |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Source | THESIS_FIST_SFH_He_P.xml |
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