Determination of Kresoxim-Methyl in Water and in Grapes by High-Performance Liquid Chromatography (HPLC) Using Photochemical-Induced Fluorescence and Dispersive Liquid-Liquid Microextraction (DLLME).
- Resource Type
- Article
- Authors
- Toloza, Carlos A. T.; Almeida, Joseany M. S.; Silva, Lillian O. P.; Macedo, Rosana C.; Lamounier, Ana Paula; Aucelio, Ricardo Q.; da Cunha, Alessandra L. M. C.
- Source
- Analytical Letters. 2020, Vol. 53 Issue 14, p2202-2221. 20p. 1 Diagram, 3 Charts, 8 Graphs.
- Subject
- *HIGH performance liquid chromatography
*BIOFLUORESCENCE
*FLUORESCENCE
*GRAPES
*WASTE products
*TANDEM mass spectrometry
*FUNGICIDES
- Language
- ISSN
- 0003-2719
A high-performance chromatographic method was developed to determine the fungicide kresoxim-methyl. Off-line photochemical derivatization was used to induce the formation of a stable and fluorescent product since the fungicide does not present natural fluorescence. Intense fluorescence at 370/430 nm was achieved by treating the analyte in solution at pH 6 to ultraviolet light for 45 s. The chromatographic conditions included isocratic elution with 50/50% (v/v) acetonitrile/water and the photochemical product appeared at a retention time of 7.2 min. The short and long term stabilities of the photoproduct were evaluated and variation of less than 5% was achieved. The limits of detection in water samples and in grapes samples were 0.019 mg kg−1 and 0.065 mg kg−1 of kresoxim- methyl residue, respectively. The linear response covered three orders of magnitude up to 10.6 mg kg−1 of kresoxim-methyl. The robustness was evaluated through a Box–Behnken experimental design showing the insignificance of all factors and their interactions. The potential interference of tebuconazole for the determination of kresoxim-methyl was studied. The use of the dispersive liquid-liquid microextraction (DLLME) allowed recoveries between 80% and 101% depending on concentration with the minimum generation of waste products. [ABSTRACT FROM AUTHOR]