Determinación de residuos de contaminantes orgánicos en miel y zumos

La agricultura moderna depende, en gran medida, de la utilización de pesticidas para controlar las plagas, las enfermedades y las malas hierbas que pueden ocasionar pérdidas en la calidad de las cosechas y disminuir su producción. El amplio uso de los pesticidas, unido a su persistencia y distribución medioambiental, origina la contaminación de las aguas, del suelo y de los alimentos. Además, el carácter lipofílico de muchos pesticidas puede provocar su acumulación en los seres humanos, al consumir los alimentos contaminados. En los últimos años, la contaminación de los alimentos y del medio ambiente por los pesticidas se ha convertido en objeto de gran interés y preocupación social debido a los posibles efectos adversos de una exposición prolongada a estos compuestos. Los pesticidas son sustancias tóxicas, por lo que diversos organismos nacionales e internacionales han establecido límites máximos de concentración en los alimentos y el agua con el fin de proteger la salud humana. Los principales objetivos de este trabajo son los siguientes: 1. El desarrollo de metodología analítica para la determinación en la miel de los residuos de pesticidas y otros contaminantes orgánicos, como los hidrocarburos aromáticos policíclicos, basada en el empleo de la dispersión de matriz en fase sólida y en la determinación cromatográfica empleando detectores selectivos de nitrógeno-fósforo y captura de electrones, así como la espectrometría de masas. 2. El desarrollo de métodos analíticos que permitan la determinación en zumos de frutas y hortalizas de los residuos de distintos grupos de pesticidas utilizando diferentes técnicas de extracción y de determinación por cromatografía de gases, así como el análisis del fungicida tiabendazol por cromatografía de líquidos

Ultrasound-assisted extraction methods for the determination of organic contaminants in solid and liquid samples

13 Pág.Ultrasound-assisted extraction is a common technique for the extraction of organic contaminants from solid samples due to its ease of application to a variety of matrices and the wide range of solvents that can be used. In recent years, many methods have combined sonication with microextraction techniques for liquid samples. Among the improvements in extraction techniques, there is an increasing interest in reducing the use of traditional organic solvents or replacing them with other less toxic solvents, such as ionic liquids due to the negligible vapour pressure of these solvents. However, these solvents are not fully green due to poor biodegradability and some toxicity to aquatic life. As a result of the growing interest in the so-called “Green Chemistry”, the use of more environmentally friendly solvents, such as deep eutectic solvents, or novel sorbents, such as magnetic nanoparticles, has been observed for the extraction of organic contaminants. This review provides an overview of the new applications of ultrasound-assisted extraction for the determination of organic contaminants, with special emphasis on the methods that implement the principles of Green Analytical Chemistry to reduce the environmental impact. In this article, the ultrasound-assisted extraction methods proposed in the last five years (2018–2022) are reviewed to update our previous review.Peer reviewe

Determination of polycyclic aromatic hydrocarbons in honey by matrix solid-phase dispersion and gas chromatography/mass spectrometry

A multiresidue method was developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in unifloral and multifloral honeys. The analytical procedure is based on the matrix solid-phase dispersion of honey on a mixture of Florisil and anhydrous sodium sulfate in small glass columns and extraction with hexane-ethyl acetate (90 + 10, v/v) with assisted sonication. The PAH residues are determined by gas chromatography with mass spectrometric detection using selected-ion monitoring. Average recoveries for all the PAHs studied were in the range of almost 80 to 101 %, with relative standard deviations of 6 to 15%. The limits of detection ranged from 0.04 to 2.9 μg/kg. The simultaneous extraction and cleanup of samples makes this method simple and rapid, with low consumption of organic solvents

Multiresidue determination of pesticides in honey by matrix solid-phase dispersion and gas chromatography with electron-capture detection

A multiresidue method was developed for the determination of 15 pesticides (organochlorines, organophosphorus compounds, pyrethroids, and other acaricides) in various commercial honeys (eucalyptus, lavender, orange, rosemary, and multifloral). The analytical procedure is based on the matrix solid-phase dispersion of honey in a mixture of Florisil and anhydrous sodium sulfate; the mixture is placed in small plastic columns and extracted with hexane-ethyl acetate (90 + 10, v/v). The pesticide residues are determined by capillary gas chromatography with electron-capture detection. Recoveries with the method at concentrations between 0.15 and 1.5 μg/g ranged from 80 to 113%, and relative standard deviations were <10% for all the pesticides studied. The pesticide detection limits were within the range 0.5-5 μg/kg for organo-chlorines, around 3 μg/kg for the chlorinated organophosphorus pesticides studied, near 15 μg/kg for fluvalinate, and about 3 μg/kg for the other pyrethroids

Determination of Emerging Contaminants in Cereals by Gas Chromatography-Tandem Mass Spectrometry

11 Pág.Cereals are staple foods for human consumption in both developed and developing countries. In order to improve agricultural outputs, resources like reclaimed water for irrigation and biosolids and manure as fertilizers are frequently used, although they may increase the input of contaminants that can potentially be absorbed by crops and enter the food chain. Emerging contaminants (human and veterinary pharmaceuticals, personal care products, surfactants, plasticizers, and industrial additives, among others) are continuously introduced in the environment from a variety sources and these contaminants may enter the food chain through plant uptake. In this study, an analytical method, based on ultrasound-assisted extraction and dispersive solid-phase cleanup, was developed for the determination of emerging contaminants from different classes in four highly consumed cereal grains (wheat, oat, barley, and rice). These analytes were selected considering the results of our previous studies carried out in soil and vegetables and those frequently detected in real samples were chosen. The target compounds selected were bisphenol A (BPA), bisphenol F (BPF), methyl paraben, propyl paraben, linear chain nonylphenol in position 4 (4-n-NP), mixture of ring and chain isomers of NP and six pharmaceutical compounds (allopurinol, mefenamic acid, carbamazepine, paracetamol, diclofenac and ibuprofen). Recoveries ranging from 68 to 119% with relative standard deviations (RSD) <18% were obtained for all the compounds except for allopurinol, with recoveries that ranged from 30 to 66% with RSD ≤ 12% and the limits of detection achieved ranged from 0.03 to 4.9 ng/g. The method was applied to the analysis of 16 cereal samples, ten were purchased in local supermarkets and the rest were collected directly from agricultural fields, five of which were fertilized with organic amendments. Bisphenol A (BPA) was detected in all samples at levels that ranged from 1.6 to 1,742 ng/g. Bisphenol F, a substitute for BPA, was also found in six samples (up to 22 ng/g). Linear 4-n-NP was found in a reduced number of samples but the mixture of NP isomers was found in all the samples, being the mean concentrations in wheat, barley, oat and rice 49, 90, 142, and 184 ng/g, respectively.This research was funded by Spanish Ministry of Economy, Industry and Competitiveness through the project RTA2014-00012C03.Departamento de Medio Ambiente y Agronomía​Peer reviewe

Multiresidue determination of pesticides in juice by solid-phase extraction and gas chromatography-mass spectrometry

A multiresidue method based on solid-phase extraction was developed for the simultaneous determination of 50 pesticides in commercial juices. The extraction procedure was carried out in C18 columns preconditioned with acetonitrile and water. The subsequent elution of pesticides was performed with a mixture of hexane-ethyl acetate (11, v/v) prior to the determination by gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC-MS-SIM), using one target and two qualifier ions. Standards were prepared spiking blank juice samples to counteract the observed matrix effect. Average recoveries for all the pesticides studied were higher than 91% with relative standard deviations lower than 9% in the concentration range of 0.02-0.1 μg/mL and the detection limits achieved ranged from 0.1 to 4.6 μg/L. The proposed method was applied to the analysis of these compounds in commercial juices and diazinon, ethion and procymidone were the pesticides encountered, although the levels found were very low. © 2004 Elsevier B.V. All rights reserved

Determination of thiabendazole in orange juice and rind by liquid chromatography with fluorescence detection and confirmation by gas chromatography/mass spectrometry after extraction by matrix solid-phase dispersion

A method was developed for the determination of thiabendazole (TBZ) in orange juice and rind based on matrix solid-phase dispersion (MSPD). TBZ was extracted with ethyl acetate and the extract was subsequently cleaned up on a solid-phase extraction column. Fungicide residues were determined by liquid chromatography with fluorescence detection. Recoveries through the method ranged from 87 to 97% with relative standard deviations ≤11%. The detection and quantitation limits were 0.15 and 0.50 μg/kg, respectively. The confirmation of TBZ residues in positive samples was performed by solid-phase microextraction followed by gas chromatography with mass spectrometric detection using selected ion monitoring. The developed method was applied to determine TBZ levels in commercial orange juices and in juice and rind of fresh oranges. The influence of storage and washing of fruits on TBZ residues was also studied

High-performance liquid chromatography multiresidue method for the determination of N-methyl carbamates in fruit and vegetable juices

A rapid multiresidue method has been developed for the analysis of N-methylcarbamate insecticides (oxamyl, methomyl, propoxur, carbofuran, carbaryl, and methiocarb) in fruit and vegetable juices. The method is based on the adsorption of the N-methyl carbamates in Florisil and the subsequent extraction of pesticides using a low volume of acetone. Residue levels in juice were determined by reversed-phase high-performance liquid chromatography with fluorescence detection after postcolumn derivatization. The separation of carbamates is performed on a C8 column with water-methanol as mobile phase. Recovery studies were performed at 500-, 100-, and 10-ng/ml fortification levels, and average recoveries obtained for carbamates ranged from 79 to 109%, with relative standard deviations between 1.4 and 9.9%. The method was found to be linear over the range assayed from 10 to 1,000 ng/ml, and the detection limits for carbamates varied from 0.8 to 1.9 ng/ml

Analysis of pesticides in honey by solid-phase extraction and gas chromatography-mass spectrometry

An analytical method for the simultaneous determination of 51 pesticides in commercial honeys was developed. Honey (10 g) was dissolved in water/methanol (7030; 10 mL) and transferred to a C18 column (1 g) preconditioned with acetonitrile and water. Pesticides were subsequently eluted with a hexane/ethyl acetate mixture (5050) and determined by gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC-MS-SIM). Spiked blank samples were used as standards to counteract the matrix effect observed in the chromatographic determination. Pesticides were confirmed by their retention times, their qualifier and target ions, and their qualifier/target abundance ratios. Recovery studies were performed at 0.1, 0.05, and 0.025 μg/g fortification levels for each pesticide, and the recoveries obtained were &gt;86% with relative standard deviations of &lt;10%. Good resolution of the pesticide mixture was achieved in ∼41 min. The detection limits of the method ranged from 0.1 to 6.1 μg/kg for the different pesticides studied. The developed method is linear over the range assayed, 25-200 μg/L, with determination coefficients of &gt;0.996. The proposed method was applied to the analysis of pesticides in honey samples, and low levels of a few pesticides (dichlofluanid, ethalfluralin, and triallate) were detected in some samples

Determination of organophosphorus pesticides in fruit juices by matrix solid-phase dispersion and gas chromatography

A rapid multiresidue method was developed for the determination of nine organophosphorus pesticides in fruit juices. The analytical procedure is based on the matrix solid-phase dispersion (MSPD) of juice samples on Florisil in small glass columns and subsequent extraction with ethyl acetate assisted by sonication. Residue levels were determined by gas chromatography with nitrogen-phosphorus detection. Spiked blank samples were used as standards to counteract the matrix effect observed in the chromatographic determination. The NPD response for all pesticides was linear in the concentration range studied with determination coefficients >0.999. Average recoveries obtained for all of the pesticides in the different juices and fortification levels were >70% with relative standard deviations of <11%. The detection limits ranged from 0.1 to 0.6μg/kg. The identity of the pesticides was confirmed by gas chromatography with mass spectrometric detection using selected ion monitoring. The proposed MSPD method was applied to determine pesticide residue levels in fruit juices sold in Spanish supermarkets. At least one pesticide was found in most of the samples, although the levels detected were very low, far from the maximum residue levels established for raw fruit