Ultrasound-assisted extraction with LC-TOF/MS identification and LC-UV determination of imazamox and its metabolites in leaves of wheat plants.
BACKGROUND
imazamox is a herbicide used in many legominous and cereal crops. There are few methods in the literature for determination of imazamox and its metabolites in plants because of the lack of commercial standards or owing to expensive and/or complex synthesis.


OBJECTIVE
To develop a method based on liquid chromatography and ultraviolet absorption detection for simultaneous determination of imazamox and its metabolites in plants.


METHODS
Sample preparation was based on ultrasound-assisted extraction (70 W power and duty cycle of 0.7 s/s for 10 min) with subsequent filtration of the extracts and clean-up and concentration prior to chromatographic separation and detection at 240 nm. The chromatographic analysis was completed in 30 min using a Luna® HILIC column. Identification and confirmatory analysis of the presence of imazamox and its metabolites in extracts from treated plants was performed by LC-TOF/MS in high resolution mode for precursor ions. The metabolites were quantified using a surrogate approach based on an imazamox standard. The method was validated by analysing wheat samples treated with 200 g per hectare of active ingredient imazamox.


RESULTS
The linear dynamic range of the calibration curve was within 0.27-600 µg/mL, with a correlation coefficient of 0.998 and precision--studied at 0.1 and 2 µg/mL--of 2.9% and 5.0% for repeatability, and 4.7% and 6.9% for reproducibility, respectively.


CONCLUSIONS
The analytical characteristics of the method make it recommendable for evaluating the metabolism of imazamox in plants.
Department of Agricultural Chemistry, C-3 Building, Campus of Rabanales, University of Córdoba, E-14071, Córdoba, Spain; Agroalimentary Excellence Campus, ceiA3, University of Córdoba, E-14071, Córdoba, Spain.
Antonia M
AM
Rojano-Delgado
Feliciano
F
Priego-Capote
Rafael
R
De Prado
María Dolores Luque
MD
de Castro
D002853:Chromatography, Liquid / Q000379:methods; D006540:Herbicides / Q000032:analysis* / Q000378:metabolism; D007093:Imidazoles / Q000032:analysis* / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D008872:Microwaves; D018515:Plant Leaves / Q000737:chemistry* / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014908:Triticum / Q000737:chemistry* / Q000378:metabolism; D014465:Ultrasonics
D006540:Herbicides; D007093:Imidazoles; C494197:imazamox
LC-TOF/MS; LC-UV separation-determination; Triticum aestivum; imazamox, metabolites; ultrasound-assisted extraction