Effect of processing on the disappearance of pesticide residues in fresh-cut lettuce: Bioavailability and dietary risk.

The aim of this research is to establish the processing factors of six pesticides durong the preparation of fresh-cut lettuce and to assess the risk of ingestion of pesticide residues associated with the consumption of the same. A field study was carried out on the dissipation of three insecticides (imidacloprid, tebufenozide, cypermethrin) and three fungicides (metalaxyl, tebuconazole, azoxystrobin) during treatment conditions simulating those used for commercial fresh-cut lettuce. A simultaneous residue analysis method is validated using QuEChERS extraction with acetonitrile and CG-MS and LC-MS/MS analysis. The residues detected after field application never exceed the established Maximum Residue Limits. The processing factors were generally less than 1 (between 0.34 for tebufenozide and 0.53 for imidacloprid), indicating that the process, as a whole, considerably reduces residue levels in processed lettuce compared to fresh lettuce. It is confirmed that cutting, followed by washing and drying, considerably reduces the residues. A matrix effect in the dialyzation of the pesticides is observed and the in vitro study of bioavailability establishes a low percentage of stomach absorption capacity (<15%). The EDI/ADI ratios found in all cases were well below their ADI values, and the dietary exposure assessed (EDI) in fresh-cut lettuce showed no concerns for consumer health.

Determination of Nine Fungicides in Grape and Wine Using QuEChERS Extraction and LC/MS/MS Analysis.

An analytic procedure was developed for the determination of the fungicides ametoctradin, boscalid, cyazofamid, dimethomorph, fenhexamid, kresoxim-methyl, mepanipyrim, metrafenone, and pyraclostrobin in grape and wine. A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure was used for the extraction. Analysis of the extract was performed by LC/triple quadrupole-MS/MS. A Poroshell 120 EC-C18 column was used with a programmed gradient mobile phase consisting of (A) acetonitrile containing 0.1% formic acid and (B) water containing 0.1% formic acid and 2 mM ammonium formate. The acceptance criteria for the method were those proposed in the SANCO guide. The method was linear for the range of concentration studied (5-100 µg/L), and R2 values were higher than 0.998 and RSD values below 18%. Recovery was over 73.2% in grape and 76.7% in wines, and there was no case of more than 100% recovery. The recovery RSDs in reproducibility conditions were below 17.13% in grape and 15.6% in wines.

Determination of natural pesticides in fresh fruits using liquid chromatography/mass spectrometry.

An analytical procedure was developed for the determination of some natural pesticides (piperonyl butoxide, nicotine, rotenone, spinosad, and abamectin B1a) in fruit matrixes. The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used for extraction. Analysis of the extract was performed by LC-electrospray ionization (ESI)-MS/MS. The ions prominent in the ESI spectra were [M+Na]+ for abamectin B1a, [M+NH4]+ for piperonyl butoxide, and [M+H]+ for the rest of the compounds. A Zorbax SB-C18 column was used with a programmed gradient mobile phase consisting of (A) water containing 0.1% formic acid and 5 mM ammonium formate, and (B) acetonitrile containing 2 mM sodium acetate. The method was linear within the investigated concentration range, displaying a calibration curve correlation factor of 0.99. The CVs obtained were below 20%, and recoveries were in the 70-110% range.

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, essay, 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.

Validation of an analytical method for the quantification of pyrethrins on lemons and apricots using high-performance liquid chromatography/mass spectrometry.

An analytical procedure has been developed for the determination of natural pyrethrins (pyrethrin I, pyrethrin II, jasmolin I, jasmolin II, cinerin I and cinerin II) in lemon and apricot. The QuEChERS method, which stands for quick, easy, cheap, effective, rugged and safe was used for extraction. Analysis of the extract was performed by liquid-chromatography-electrospray ionisation-tandem mass spectrometry. The ions prominent in the ESI spectra were [M+H]+ for the six compounds. A Zorbax SB-C18 column was used with a programmed gradient mobile phase consisting of (A) water containing 0.1% formic acid and 5 mM ammonium formate and (B) ACN. The method was linear within the investigated concentration range, displaying a calibration curve correlation factor of 0.99. The coefficients of variation obtained (RSD) were below 20% and the recoveries were in the 70-110% range.

HCH and DDT residues in human fat in the population of Murcia (Spain).

In the Mediterranean province of Murcia (SE Spain) around 610,000 hectares of land are devoted to agriculture and organochlorine insecticide use has been common in the region for many years. To investigate HCH and DDT (isomers and metabolites) residues, a total of 231 fat samples were taken from the general population and analyzed. Organochlorine residues were found in 63.2 % of the samples. The pattern of overspreading by these substances in this part of the world is similar to that described by different authors in other countries. p,p'-DDE, beta-HCH and lindane residues, in this order, show the highest occurrence in the region and also the highest mean levels. Areas devoted to greenhouses, traditional dry farming of paprika pepper, and traditional horticultural cultivation are the most contaminated. Therefore, the past use of DDT and the actual employment of lindane seem to be reflected in the residents of these areas.

Dissipation rates of cyprodinil and fludioxonil in lettuce and table grape in the field and under cold storage conditions.

Two fungicides (cyprodinil and fludioxonil) have recently been used in southeast Spain to control disease in lettuce and grape. Gas chromatography with a nitrogen-phosphorus detector (GC-NPD) was used to study the disappearance of these compounds from crops under field conditions and during refrigeration. Residual values 21 days after application were below the maximum residue limit (MRL = 0.05 mg kg(-1)) established by Spanish law in the field experiment for both compounds. However, with the exception of fludioxonil in lettuce, residues were above the MRL in the refrigerated farm produce for both fungicides. The half-lives were 3-6 times greater under refrigeration.

Molecular and morphologic characterization of superficial- and deep-subcutaneous adipose tissue subdivisions in human obesity.

OBJECTIVE: Human abdominal subcutaneous white adipose tissue (SAT) is composed of two different subcompartments: a "superficial" SAT (SSAT), located between the skin and a fibrous-fascia plane; and a deeper SAT, located under this fibrous fascia plane, indicated as "deep" SAT (DSAT). DESIGN AND METHODS: In order to investigate whether SSAT and DSAT have different molecular and morphological features, paired SSAT/DSAT biopsies were collected from 10 female obese patients and used for microarray and morphologic analysis. The stroma-vascular fraction cells were also isolated from both depots and cultured in vitro to assess the lipid accumulation rate. RESULTS: SSAT and DSAT displayed different patterns of gene expression, mainly for metabolic and inflammatory genes, respectively. Detailed gene expression analysis indicated that several metabolic genes, including adiponectin, are preferentially expressed in SSAT, whereas inflammatory genes are over-expressed in DSAT. Despite a similar lipid accumulation rate in vitro, in vivo SSAT showed a significant adipocyte hypertrophy together with a significantly lower inflammatory infiltration and vascular vessel lumen mean size, when compared to DSAT. CONCLUSIONS: These data show that, SSAT and DSAT are functionally and morphologically different and emphasize the importance of considering independent these two adipose depots when investigating SAT biology and obesity complications.

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.

Dissipation of fenoxycarb and pyriproxyfen in fresh and canned peach.

The objective of this work was to determine the dissipation of fenoxycarb and pyriproxyfen in fresh and canned peaches in order to know the levels of residues that can reach consumers in real circumstances. Two field dissipation studies were carried out, one of them at the pre-harvest interval (PHI) with good agricultural practice (GAP) and the other one in a situation of critical agricultural practice (CAP). Two canning dissipation studies were carried out for samples from both agricultural situations in an industrial pilot plant and the dissipation was determined in each relevant step. An analytical methodology was used including acetone-dichloromethane extraction, purification and analysis by liquid chromatography and diode array detection (LC-DAD) with a limit of quantification (LOQ) of 0.05 mg/kg. It was validated under SANCO/10232/2006 Guidelines. These pesticides complied with the official maximum residue limits (MRLs) in peaches at the PHI with good agricultural practices. In hypothetical situation of a second application at the PHI, fenoxycarb and pyriproxyfen residues were above the MRLs in peaches. The canning study reduced the residues to no detectable levels in the cans for consumers.

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 microm 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.

Analysis of pesticide residues using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) pesticide multiresidue method in combination with gas and liquid chromatography and tandem mass spectrometric detection.

The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 80 pesticides belonging to various chemical classes from various types of representative commodities with low lipid contents. A mixture of 38 pesticides amenable to gas chromatography (GC) were quantitatively recovered from spiked lemon, raisins, wheat flour and cucumber, and determined using gas chromatography-tandem mass spectrometry (GC-MS/MS). An additional mixture of 42 pesticides were recovered from oranges, red wine, red grapes, raisins and wheat flour, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination. The pesticides chosen for this study included many of the most frequently detected ones and/or those that are most often found to violate the maximum residue limit (MRL) in food samples, some compounds that have only recently been introduced, as well as a few other miscellaneous compounds. The method employed involved initial extraction in a water/acetonitrile system, an extraction/partitioning step after the addition of salt, and a cleanup step utilizing dispersive solid-phase extraction (D-SPE); this combination ensured that it was a rapid, simple and cost-effective procedure. The spiking levels for the recovery experiments were 0.005, 0.01, 0.02 and 0.2 mg kg(-1) for GC-MS/MS analyses, and 0.01 and 0.1 mg kg(-1) for LC-MS/MS analyses. Adequate pesticide quantification and identity confirmation were attained, even at the lowest concentration levels, considering the high signal-to-noise ratios, the very good accuracies and precisions, as well as the good matches between the observed ion ratios. Mean recoveries mostly ranged between 70 and 110% (98% on average), and relative standard deviations (RSD) were generally below 10% (4.3% on average). The use of analyte protectants during GC analysis was demonstrated to provide a good alternative to the use of matrix-matched standards to minimize matrix-effect-related errors. Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity/pesticide combinations.