Liquid chromatography quadrupole time-of-flight tandem mass spectrometry following solid-phase extraction for the selective determination of fungicides in wines

FONTANA, A.; RODRIGUEZ, I.; RAMIL, M.; ALTAMIRANO, J.; CELA, R.

Montevideo

Workshop; Latin American Pesticide Residue Workshop Food and Environment; 2011

Universidad de la República, Facultad de Química y la Cátedra de Farmacognosia y Productos Naturales

Fungicides are extensively used to prevent and control fungal attacks, representing the main group of pesticides applied on vineyards. With a few exceptions, the presence of fungicides in wine is not regulated being an issue of concern for consumers and producers. In this sense, the determination of fungicide residues in wines is necessary for food safety monitoring and future regulatory purposes.The objective of this work was the development and validation of a method for the identification and quantification of thirteen fungicides, belonging to different chemical classes, in wines using SPE followed by LC-QTOF-MS/MS. Under optimum working conditions, extraction and purification of target analytes was carried out simultaneously with a reversed-phase Oasis HLB (200 mg) SPE cartridge, using acetonitrile as elution solvent. Fungicides were determined operating the electrospray source in the positive ionization mode, with MS/MS conditions adjusted to obtain at least two intense product ions per compound, or registering two transitions per species when a single product was noticed. Considering external calibration, with standards prepared in acetontrile: water (1:1), as quantification technique the overall recoveries of the procedure ranged between 81% and 114% for red and white wine samples spiked at different concentrations between 5 and 100 ng mL-1. Relative standard deviations of the above data stayed below 10% and the limits of quantification (LOQs) of the method, varied between 0.1 ng mL-1 for cyprodinil (CYP) and 0.7 ng mL-1 for myclobutanil (MYC). The optimized method was applied to seventeen commercial wines produced in Spain and obtained from local supermarkets. Nine fungicides were determined, at levels above the LOQs of the method in the samples. The maximum concentrations and the highest occurrence frequencies corresponded to metalaxyl (MET) and iprovalicarb (IPR).