A. Barba

Multiresidue method for the rapid determination – in grape, must and wine – of fungicides frequently used on vineyards

A rapid multiresidue gas chromatographic method for determining 17 fungicides in grapes, must and wine, widely used on vineyards, is described. A simple on-line microextraction method for isolation of fungicides was used. Nitrogen-phosphorus and electron-capture detection were used for the identification and quantitation of pesticides. For confirmation, mass spectrometic detection was used. Because of the high selectivity of both detection methods, no clean-up was necessary. The regression coefficients relating to linearity were at least 0.994. Recoveries from spiked grapes, must and wine samples ranged from 78 to 107% and relative standard deviations were not higher than 14%. Individual detection limits were in the range 0.02-0.1 ng. Limits of quantification varied from 0.01 to 0.05 mg/kg, smaller in all cases than the maximum residue limits set down by the legislations of Spain, France and Italy, the main wine-producing countries of the European Union. Only for fludioxonil and hexaconazole do the limits of quantification coincide with the maximum residue limits (0.05 mg/kg) established by the Spanish legislation.

Evolution of residual levels of six pesticides during elaboration of red wines. Effect of wine-making procedures in their dissappearance.

The effect of wine-making procedures on the concentrations of six pesticides (chlorpyrifos, penconazole, fenarimol, vinclozolin, metalaxyl, and mancozeb) in red wines has been studied. During maceration stage (4 days), the percentage remaining of chlorpyrifos, penconazole, and metalaxyl was approximately 90%, whereas that of fenarimol, vinclozolin, and mancozeb is somewhat smaller (74-67%). The residual levels found in pressed must were </=20%, except for metalaxyl (69%). From the whole concentration of chlorpyrifos in must, 85% is eliminated from the racking step; clarification (bentonite plus gelatin) eliminates 43% of the product found in the decanted wine, and with filtration, all of the residue is eliminated. Penconazole and mancozeb are retained on the lees in proportions of 43 and 31%, respectively. The eliminated percentage of vinclozolin after racking is 29%, whereas clarification and filtration reduce its proportion in the wine to 33 and 28%, respectively. Finally, fenarimol and metalaxyl are eliminated in smaller proportion with the realization of these processes.

Determination of chlorpyrifos, penconazole, fenarimol, vinclozolin and metalaxyl in grapes, must and wine by on-line microextraction and gas chromatography

A rapid gas chromatographic method for determination of residue levels of one insecticide (chlorpyrifos) and four fungicides (penconazole, fenarimol, vinclozolin and metalaxyl) in grapes, must and wine is described. An on-line microextraction method was used. The matrix, once extracted with a mixture of acetone-dichloromethane (1:1, v/v) was filtered and concentrated. Electron-capture detection for chlorpyrifos, penconazole, fenarimol and vinclozolin and mass-selective detection in the selected-ion monitoring mode for metalaxyl were utilised. No clean-up was necessary because there were no interferences in the area of interest of the chromatogram. Linearity of both detectors, in the range 0.02-2 ng/microliter, was checked. In all cases, the correlation coefficient was the same or superior to 0.997. Recoveries from spiked grapes, must and wine ranged from 78% to 101% (fortification level, 0.1-1 mg/kg). Limits of determination were between 0.01 mg/kg for metalaxyl and 0.001 mg/kg for vinclozolin.

Multiresidue method for the rapid determination of organophosphorus insecticides in grapes, must and wine

A rapid multiresidue gas chromatographic method for determining 12 insecticides in grapes, must and wine is described. A simple on-line microextraction method for isolating frequently applied insecticides on vineyard is used. The matrix, once extracted with an acetone-dichloromethane (1:1, v/v) mixture, was filtered and concentrated. Nitrogen-phosphorus detection (NPD) and electron-capture detection (ECD) were used to identify and quantify the insecticides, the findings being confirmed using mass spectrometric detection (MSD). No clean-up was necessary for either NPD or ECD. The regression coefficients relating to linearity were at least 0.99. Recoveries from spiked grape, must and wine samples ranged from 80 to 108% and relative standard deviations were no higher than 16% in the most unfavourable case. Individual detection limits were in the range 0.02-0.1 ng. Limits of quantification varied from 0.01 to 0.05 mg kg(-1), which are below the maximum residue limits set by the legislation of the main wine-producing countries of the European Union. Only in the case of methidathion and quinalphos were the limits of quantification equivalent to the maximum residue limits (0.05 mg kg(-1)) established by Spanish and French legislation, respectively.

Removal of famoxadone, fluquinconazole and trifloxystrobin residues in red wines: Effects of clarification and filtration processes

The effects of six clarification agents [egg albumin, blood albumin, bentonite + gelatine, charcoal, polyvinylpolypyrrolidine (PVPP) and silica gel] on the removal of residues of three fungicides (famoxadone, fluquinconazole and trifloxystrobin) applied directly to a racked red wine, elaborated from Monastrell variety grapes from the D.O. Region of Jumilla (Murcia, Spain) were studied. The clarified wines were filtered with 0.45 μ m nylon filters to determine the influence of this winemaking process in the disappearance of fungicide residues. Analytical determination of fluquinconazole and trifloxystrobin was performed by gas chromatography with electron captor detector (ECD), while that of famoxadone using an HPLC equipped with a diode array detector (DAD). Generally, trifloxystrobin is the fungicide that is the lowest persistent one in wines, except in the egg albumin study whereas, the most persistent one is fluquinconazole. The elimination depends on the nature of the active ingredient, though the water stability in the presence of light within it has more influence than the solubility and polarity of the product itself. The most effective clarifying agents were the charcoal and PVPP. The silica gel and bentonite plus gelatine were not enough to reduce considerably the residual contents in the wine clarified with them. In general terms, filtration is not an effective step in the elimination of wine residues. The greatest removal after filtration is obtained in wines clarified with egg albumine and bentonite plus gelatine, and the lowest in those clarified with PVPP.

Effect of the use of recent commercial fungicides [under good and critical agricultural practices] on the aroma composition of Monastrell red wines.

In the paper, the effect of several fungicide residues (famoxadone, fenhexamid, fluquinconazole, kresoxim-methyl, quinoxyfen and trifloxystrobin) has been studied in relation to the aroma composition of Monastrell red wines in terms of each compound concentration and OAV (Odour Activity Value) values. Two fungicide treatments were carried out with authorized formulates following the manufacturer doses. The first one was carried out under good agricultural practices (GAP), obeying the preharvest interval, and the second one under critical agricultural practices (CAP), applying at the day of harvesting. The wines obtained in the thirteen trials (one control, six with treated grapes obeying the preharvest interval and six treated at the day of harvesting or at most unfavourable conditions) were analysed by stir bar sorptive extraction and gas chromatography-mass spectrometry (SBSE-GC-MS). The method proposed showed good linearity over the concentration range tested, with correlation coefficients higher than 0.9 for all the analytes. The reproducibility and repeatability of the method was estimated between 1.0 and 18.52%. The detection and quantification limits of all analytes were lower than the concentration found in these Monastrell wines. The identified wine volatile compounds have been grouped according to: ethyl esters, acetates, C(6) compounds, terpenoids, acids and ethyl acetate, 3-methyl-1-butanol, 2-phenylethanol and benzaldehyde, as individual level. As results, it was observed that all fungicide treatments significantly affect the wine aroma composition. Each group of compounds has been associated to sensorial descriptor series (fatty, floral, fruity, herbaceous, solvent, rose and vinous), resulting that the best sensory valuated wines were the ones treated with fluquinconazole and fenhexamid under GAP.

Phenolic compounds and antioxidant activity of red wine made from grapes treated with different fungicides.

The effect of treating grapes with six fungicides, applied under critical agricultural practices (CAP) on levels of phenolic compounds and antioxidant activity of red wines of Monastrell variety was studied. Vinifications were performed through addition of active dry yeast (ADY). Measurement of phenolic compounds was made with HPLC-DAD. Determination of antioxidant activity was through reaction of the wine sample with the DPPH radical. The wine prepared from grapes treated with quinoxyfen shows a greater increase of phenolic compounds than the control wine. In contrast, the wine obtained from grapes treated with trifloxystrobin showed lower total concentration of phenolic compounds, including stilbenes, whilst treatments with kresoxim-methyl, fluquinconazole, and famoxadone slightly reduced their content. Hence, the use of these last four fungicides could cause a decrease in possible health benefits to consumers. Antioxidant activity hardly varied in the assays with quinoxyfen, fluquinconazole and famoxadone, and decreased in the other wines.

Disappearance of endosulfan residues from seawater and sediment under laboratory conditions

The dissipation rate of endosulfan isomers (α and β) in seawater and sediment was studied. The disappearance rate of both isomers from seawater and pure water was compared, and the same measurements were made in both sterile and unsterile marine sediment. Flasks of water and sediment, fortified with a dispersion of a commercial endosulfan 350 g litre−1 EC, Protodan 35®, were incubated under laboratory light at room temperature for 82 days. A micro on-line extraction method and GC-ECD was used to determine the pesticide and its metabolites. The dissipation of endosulfan (in two phases of first-order kinetics) occurred more rapidly in seawater than in pure water. At the end of the experiment, the concentration of α-endosulfan in sterile sediment was four times greater than in unsterile sediment, while the dissipation rate of β-endosulfan in unsterile sediment was approximately double that observed in sterile sediment. The dissipation of both forms in sediment occurred in a single stage. Endosulfan β-isomer was more persistent than α-isomer in both sterile and unsterile sediment. Dissipation of endosulfan sum of α- and β-isomers in sediment at the end of the experiment ranged from 80% (sterile) to 95% (unsterile). Endosulfan sulfate was detected in water and sediment as the main metabolite. © 2000 Society of Chemical Industry

Determination of sixteen pesticides in peppers using high-performance liquid chromatography/mass spectrometry

A method for the detection and quantification of 16 pesticides: flufenoxuron, fenoxycarb, dimethomorph, acetamiprid, imidacloprid, lufenuron, thiacloprid, thiabendazole, thiophanate-methyl, spinosad, fenbutatin oxide, methoxyfenozide, oxamyl, clothianidin, thiamethoxam and carbendazim has been developed based on high-performance liquid chromatography-mass spectrometry. Pesticide residues were extracted from the samples according to the QuEChERS method which stands for quick, esay, cheap, effective, rugged and safe. Homogenised analytical portions (10 g ± 0.1) of samples of peppers were spiked at two levels (10 and 100 μg Kg−1) with a small volume of an appropriate standard mixture solution containing each pesticide. Analyses were performed using electrospray ionization (ESI) and a MSD trap system. Chromatography separation was achieved using a ZORBAX SB-C18 3.5 μm particle size analytical column, 2.1 × 50 mm from Agilent, with gradient elution at a flow-rate of 0.4 mL/min with mobile phases: waters-0.1 % HCOOH-5 mM HCOONH4 and MeOH-5 mM HCOONH4. The method has been validated based on the SANCO European Guidelines. Under the optimized conditions the recoveries (n = 7) were in the range 70–110 % with satisfactory precision (CV ≤ 20 %). A linear dynamic range was obtained over a range of concentrations from 10 to 100 μg Kg−1 for each of the analytes, with correlation coefficients >0.997.

Dissipation of insect growth regulators in fresh and canned fruits

The objective of the study was to determine the dissipation of insect growth regulators in fresh and canned mandarin and apricot to determine the exposure to them. Field studies were carried out in the preharvest period with good agricultural practices (GAP) and in critical agricultural practices. The processing studies were carried out in each relevant step in a pilot plant. A validated methodology was developed (limit of quantification of 0.05 mg kg−1 for apricots, 0.10 mg kg−1 for mandarin) including acetone–dichloromethane extraction, cleanup, and liquid chromatography-diode array detection. The pesticides complied with the maximum residue limits (MRLs) except pyriproxyfen, which has not been authorized in apricots, and it did not comply with its MRL for peaches. The dissipation rates (t 1/2) with GAP were fenoxycarb-apricot > pyriproxyfen-apricot > fenoxycarb-mandarin > pyriproxyfen-mandarin. In the processing studies, there was only residue transference in the canning of apricots. All final cans contained residues much lower than the MRLs.