Feasibility and application of an HPLC/UVD to determine dinotefuran and its shorter wavelength metabolites residues in melon with tandem mass confirmation

• Published in: Food chemistry 2013-01, Vol.136 (2), p.1038-1046
• Main Authors: Rahman, Md. Musfiqur, Park, Jong-Hyouk, Abd El-Aty, A.M., Choi, Jeong-Heui, Yang, Angel, Park, Ki Hun, Nashir Uddin Al Mahmud, Md, Im, Geon-Jae, Shim, Jae-Han
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Chromatography, High Pressure Liquid - instrumentation; Chromatography, High Pressure Liquid - methods; Cucurbitaceae - chemistry; Cucurbitaceae - metabolism; Dinotefuran; Food Contamination - analysis; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Guanidines - analysis; Guanidines - isolation & purification; Guanidines - metabolism; HPLC–UVD; Insecticides - analysis; Insecticides - isolation & purification; Insecticides - metabolism; Matrix interaction; Metabolites; Neonicotinoids; Nitro Compounds - analysis; Nitro Compounds - isolation & purification; Nitro Compounds - metabolism; Pesticide Residues - analysis; Pesticide Residues - isolation & purification; Pesticide Residues - metabolism; Solid Phase Extraction; SPE clean-up; Tandem Mass Spectrometry
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2012.08.064

► A new HPLC method was developed for the determination of dinotefuran and its metabolites. ► LC–ESI–MS/MS in positive ion mode using MRM was used for confirmation. ► The method provides an adequate sensitivity and performance in melon fruits. ► This is the first report for the determination of dinotefuran and its metabolites using UVD. A new analytical method was developed for dinotefuran and its metabolites, MNG, UF, and DN, in melon using high-performance liquid chromatography (HPLC) coupled with an ultraviolet detector (UVD). Due to shorter wavelength, lower sensitivity to UV detection, and high water miscibility of some metabolites, QuEChERs acetate-buffered version was modified for extraction and purification. Mobile phases with different ion pairing or ionisation agents were tested in different reverse phase columns, and ammonium bicarbonate buffer was found as the best choice to increase the sensitivity of target analytes to the UV detector. After failure of dispersive SPE clean-up with primary secondary amine, different solid phase extraction cartridges (SPE) were used to check the protecting capability of analytes against matrix interference. Finally, samples were extracted with a simple and rapid method using acetonitrile and salts, and purified through C18SPE. The method was validated at two spiking levels (three replicates for each) in the matrix. Good recoveries were observed for all of the analytes and ranged between 70.6% and 93.5%, with relative standard deviations of less than 10%. Calibration curves were linear over the calibration ranges for all the analytes with r2⩾0.998. Limits of detection ranged from 0.02 to 0.05mgkg−1, whereas limits of quantitation ranged from 0.06 to 0.16mgkg−1 for dinotefuran and its metabolites. The method was successfully applied to real samples, where dinotefuran and UF residues were found in the field-incurred melon samples. Residues were confirmed via LC–tandem mass spectrometry (LC–MS/MS) in positive-ion electrospray ionisation (ESI+) mode.