RESUMEN
One of the recent trends in Analytical Chemistry is the development of economic, quick and easy hyphenated methods to be used in a field that includes analytes of different classes and physicochemical properties. In this work a multi-residue method was developed for the simultaneous determination of 28 xenobiotics (polar and hydrophilic) using hydrophilic interaction liquid chromatography technique (HILIC) coupled with triple quadrupole mass spectrometry (LC-MS/MS) technology. The scope of the method includes plant growth regulators (chlormequat, daminozide, diquat, maleic hydrazide, mepiquat, paraquat), pesticides (cyromazine, the metabolite of the fungicide propineb PTU (propylenethiourea), amitrole), various multiclass antibiotics (tetracyclines, sulfonamides quinolones, kasugamycin and mycotoxins (aflatoxin B1, B2, fumonisin B1 and ochratoxin A). Isolation of the analytes from the matrix was achieved with a fast and effective technique. The validation of the multi-residue method was performed at the levels: 10 µg/kg and 100 µg/kg in the following representative substrates: fruits-vegetables (apples, apricots, lettuce and onions), cereals and pulses (flour and chickpeas), animal products (milk and meat) and cereal based baby foods. The method was validated taking into consideration EU guidelines and showed acceptable linearity (r ≥ 0.99), accuracy with recoveries between 70 and 120% and precision with RSD ≤ 20% for the majority of the analytes studied. For the analytes that presented accuracy and precision values outside the acceptable limits the method still is able to serve as a semi-quantitative method. The matrix effect, the limits of detection and quantification were also estimated and compared with the current EU MRLs (Maximum Residue Levels) and FAO/WHO MLs (Maximum Levels) or CXLs (Codex Maximum Residue Limits). The combined and expanded uncertainty of the method for each analyte per substrate, was also estimated.
Asunto(s)
Cromatografía Liquida/métodos , Contaminación de Alimentos/análisis , Micotoxinas/análisis , Residuos de Plaguicidas/análisis , Preparaciones Farmacéuticas/análisis , Reguladores del Crecimiento de las Plantas/análisis , Espectrometría de Masas en Tándem/métodos , Espectrometría de Masa por Ionización de Electrospray/métodos , Medicina VeterinariaRESUMEN
The objective of this study was to investigate if milk from dairy sheep and goats, fed mainly with supplementary feed during the winter months, was contaminated with pesticides residues. Tauwo hundred milk samples from sheep and goats were collected from 10 farms of each animals. The sheep and goats farms were selected from those which represent common conventional production and feeding systems in Greece. Milk and feed samples (alfalfa hay, wheat straw, shrubs, pasture and concentrates) were taken from each farm to analyze for pesticides residues. The results showed that the summation operatorendosulfan was the main pesticide residue which was detected in all the concentrates samples at a mean concentration of 5.36 mgkg(-1), which is much higher from the maximum residue level (MRL). In addition, the summation operatorendosulfan was also detected in all the alfalfa hay samples but at a mean concentration of 0.10 mgkg(-1) which is lower than the MRL. The mean concentrations of endosulfan alpha and beta were 2.82 and 2.39 mgkg(-1) in the concentrates samples and 0.08 and 0.02 mgkg(-1) respectively in alfalfa hay samples. In the wheat straw, shrubs and pasture samples no pesticides residues were detected. No pesticide residues were also detected in milk samples of sheep and goats. Thus, this milk from the farms sampled presents no human health risks as far as the contaminants analyzed concerned.