Since the study of organic fluorinated pesticides has been a noticeable field in the seaking of efficient pesticides, the research of their structure-activity relationships be-comes more and more important. If the str...Since the study of organic fluorinated pesticides has been a noticeable field in the seaking of efficient pesticides, the research of their structure-activity relationships be-comes more and more important. If the structure features of the chemicals are consid-ered as pattern parameters, and the activities of pesticides are discretized into classes,then the quantitative structure-activity relationship (QSAR) problem can be treated by cluster analysis. Hence, the clustering method of constellation graph is employed to identify the QSAR of fluorinated organic pesticides. In order to obtain better clustering results, the weights of star-tracks are optimized by the Lagrange operator method and good results are achieved.展开更多
With high performance liquid chromatography, the concentrations of α-endosulfan, DDE, parathion methyl, isoproturon, atrazine, carbaryl and carbofuran were determined in farmed raised fish Labeo rohita of two weight ...With high performance liquid chromatography, the concentrations of α-endosulfan, DDE, parathion methyl, isoproturon, atrazine, carbaryl and carbofuran were determined in farmed raised fish Labeo rohita of two weight groups. All these pesticide residues were detected in fish meat samples. All these pesticide residues except isoproturon were identified in soil sediments, whereas all these pesticide residues except isoproturon, carbaryl and DDE were also present in water samples. DDT, heptachlor, β-endosulfan, chlorpyrifos, dimethoate, captan, cypermethrin, chlorobromuron and chlorotoluron were absent in all samples of water, sediments and fish flesh. The pesticide residues levels were in order of parathion methyl 〉 DDE 〉 carbofuran 〉 atrazine 〉 α-endosulfan 〉 isoproturan 〉 carbaryl. The concentrations of pesticides were higher in fish weighing 800 -1 300 g than in those weighing 250 -750 g. The DDE was remained highest in sediments, while that was not detected in water samples. The pesticides （endosulfan, parathion methyl, atrazine and carbofuran） had crossed their MRL values （0.001 μg/g） in water samples.展开更多
文摘Since the study of organic fluorinated pesticides has been a noticeable field in the seaking of efficient pesticides, the research of their structure-activity relationships be-comes more and more important. If the structure features of the chemicals are consid-ered as pattern parameters, and the activities of pesticides are discretized into classes,then the quantitative structure-activity relationship (QSAR) problem can be treated by cluster analysis. Hence, the clustering method of constellation graph is employed to identify the QSAR of fluorinated organic pesticides. In order to obtain better clustering results, the weights of star-tracks are optimized by the Lagrange operator method and good results are achieved.
文摘With high performance liquid chromatography, the concentrations of α-endosulfan, DDE, parathion methyl, isoproturon, atrazine, carbaryl and carbofuran were determined in farmed raised fish Labeo rohita of two weight groups. All these pesticide residues were detected in fish meat samples. All these pesticide residues except isoproturon were identified in soil sediments, whereas all these pesticide residues except isoproturon, carbaryl and DDE were also present in water samples. DDT, heptachlor, β-endosulfan, chlorpyrifos, dimethoate, captan, cypermethrin, chlorobromuron and chlorotoluron were absent in all samples of water, sediments and fish flesh. The pesticide residues levels were in order of parathion methyl 〉 DDE 〉 carbofuran 〉 atrazine 〉 α-endosulfan 〉 isoproturan 〉 carbaryl. The concentrations of pesticides were higher in fish weighing 800 -1 300 g than in those weighing 250 -750 g. The DDE was remained highest in sediments, while that was not detected in water samples. The pesticides （endosulfan, parathion methyl, atrazine and carbofuran） had crossed their MRL values （0.001 μg/g） in water samples.
