US EPA

1180391 

Journal Article 

Determination of diflubenzuron and its main metabolites in forestry matrices by Liquid chromatography with on-line diode-array and electrochemical detection 

Rodriguez, E; Barrio, RJ; Goicolea, A; de Balugera, ZG 

1999 

Yes 

Analytica Chimica Acta
ISSN: 0003-2670
EISSN: 1873-4324 

384 

1 

63-70 

English 

10.1016/S0003-2670(98)00805-8 

WOS:000079233000007 

A liquid chromatography (LC) method with on-line diode-array (DAD) and electrochemical detection (ED) has been developed for the determination of the pesticide diflubenzuron (DFB) and its main metabolites: 2,6-diflurobenzamide (2,6-DFBA), 4-chlorophenylurea (4-CPU), 4-chloroacetanilide (4-CAA), 4-chloroaniline (4-CA) and N-methyl-4-chloroaniline (NM-4-CA) in forestry matrices. Liquid chromatography was performed on a Spherisorb C18 column 5μm (4.1x150mm), using acetonitrile/methanol/citrate-disodium hydrogenphosphate buffer (50:2:48) at pH 7 as mobile phase, pumped at a flow rate of 1mlmin-1. The electrochemical study of the compounds proves the oxidation processes of 4-CPU, 4-CA, NM-4-CA and DFB on a glassy carbon electrode, which allows to determine them by oxidative amperometric detection. The amperometric detector equipped with a glassy carbon working electrode was operated at +1350mV vs Ag/AgCl. The DAD detector was set at 245 and 260nm, where the compounds show secondary maxima of absorbance which do not interfere with the matrix. The detection limits were 2.0-25.2μgl-1 for the DAD detection and 0.07-1.8μgl-1 for the amperometric detection. The method was applied to the determination of the pesticide and these metabolites in pine-needles. Samples were extracted into acetonitrile and further cleaned-up by solid-phase extraction through aminopropyl cartridges. Recoveries of the compounds from supplied pine-needle samples were higher than 90% in most of the cases, with relative standard deviations lower than 3.7%. Copyright (C) 1999 Elsevier Science B.V. 

liquid chromatography; diode-array detection; electrochemical detection; diflubenzuron; pesticides; forestry