title: A novel inhibitory kinetic fluorimetric method for the determination of trace methomyl in environmental samples.
abstract: A novel inhibitory kinetic fluorimetric method for the determination of trace methomyl was proposed. It was shown that the Fenton reagent oxidized rhodamine B in acid medium which enabled the fluorescence quenching of the latter. The presence of trace methomyl clearly inhibited the reaction. Upon addition of EDTA, a good linear relationship between the inhibitory effect and the concentration of methomyl was observed, together with improved stabilization and sensitivity. Factors affecting the determination of trace methomyl were investigated systematically. Under the optimum conditions, the linear range for the determination of methomyl was 0.04-2.2 microg/mL; the detection limit and the quantification limit for methomyl were 0.011 and 0.037 microg/mL, respectively. The proposed method was applied to the determination of methomyl in four environmental soil samples, six environmental water samples and one synthetic sample; the results were compared with those determined by the HPLC method. The recoveries and the relative errors were 83.5-101.2 and 0.47-2.02%, respectively. The possible reaction mechanism has also been discussed.
authors.affiliation: School of Chemistry and Environmental Science, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, Henan 453007, People's Republic of China. fanjing@henannu.edu.cn
authors.forename: Jing
authors.initials: J
authors.lastname: Fan
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Shao
authors.forename: Haizhu
authors.initials: H
authors.lastname: Xu
authors.forename: Suling
authors.initials: S
authors.lastname: Feng
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry; D005470:Fluorometry / Q000379:methods*; D005618:Fresh Water / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D008724:Methomyl / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D010573:Pesticide Residues / Q000032:analysis*; D012235:Rhodamines / Q000737:chemistry; D012987:Soil / Q000032:analysis*; D013997:Time Factors
chemical_list: C045076:Fenton's reagent; D005456:Fluorescent Dyes; D010573:Pesticide Residues; D012235:Rhodamines; D012987:Soil; D008724:Methomyl; D006861:Hydrogen Peroxide; D007501:Iron; C029773:rhodamine B