Development of a SPME-GC-ECD methodology for selected pesticides in must and wine samples

Pesticide Residues in Mandarins: Three-Year Monitoring Results

The demand of plant production product use has increased because of the current system of citrus production, which prioritizes high agricultural yields. Therefore, the monitoring of pesticide residues in citrus fruits and other agricultural products and their impacts on human health and food security are of great concern. This study aims to determine multi-class pesticides including highly polar residues in satsuma mandarins. A total of 226 mandarin samples were collected over three consecutive harvesting years from 2019 to 2021 in the Izmir region of Turkey. Targeted compounds included pesticides and metabolites with European Union (EU) regulatory levels, plus other non-approved residues and highly polar compounds. The residues excluding highly polar substances were analyzed by applying the quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) determination for 434 analytes and gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) determination for 71 analytes. For six highly polar pesticides, sample preparation was based on Quick Polar Pesticides (QuPPe) extraction. The polar residues were determined by LC-MS/MS using internal standards. Forty different residues, including two highly polar substances, were recorded in mandarin samples through three harvesting years. In 8.4% of the samples, no quantifiable residues were detected, whereas 207 samples contained at least one residue. The maximum residue level (MRL) exceedances were recorded for 22.1% of the samples. The two most frequently found pesticides were phosphonic acid and spirotetramat, with an incidence rate of 48.7% and 46.5%, respectively. The concentration of phosphonic acid and spirotetramat in mandarin samples varied from 0.026 to 39.386 mg kg^-1 and from 0.010 to 1.485 mg kg^-1, respectively. The results will enable researchers and regulatory authorities to assess the extent of pesticide presence, identify potential risks, and take necessary measures to ensure the safety of satsuma mandarins for consumers.

Quantification of 363 Pesticides in Leafy Vegetables (Dill, Rocket and Parsley) in the Turkey Market by Using QuEChERS with LC-MS/MS and GC-MS/MS

Contamination of agricultural products with pesticide residues is a growing concern due to their adverse health effects and increasing worldwide usage of pesticides. In 2021 a total of 200 samples of green leafy vegetables, including 80 dill, 80 rocket and 40 parsley, purchased from greengrocer shops, markets and bazaars in Corum Province, Turkey, were monitored for pesticide residues. In green leafy vegetables, 363 pesticides were analyzed using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation, followed by liquid chromatography coupled to mass spectrometry (LC-MS/MS) for 311 residues and gas chromatography coupled to mass spectrometry (GC-MS/MS) for 52 residues. The method was in-house validated at two fortification levels, and satisfactory recoveries and precisions were achieved for all residues. No quantifiable residues were found in 35% of the samples, whereas 43 residues belonging to 24 different chemical classes were detected in 130 green leafy vegetables. Among the green leafy vegetables, the highest occurrence frequency was recorded in the rocket, followed by dill and parsley. In 46% of the green leafy vegetables, the residue levels exceeded European Union Maximum Residue Levels (EU MRLs). The most frequently detected pesticides were pendimethalin (22.5%), diuron (38.7%) and pymetrozine (52.5%) in dill, rocket and parsley, respectively.

A Comprehensive Review on Metal Organic Framework Based Preconcentration Strategies for Chromatographic Analysis of Organic Pollutants

Organic pollutants (OPs) are of worldwide concern for being hazardous to human existence and natural flora and fauna in view of their contaminating nature, bio-aggregation properties and long range movement abilities in environment. Metal organic frameworks (MOFs) are a new kind of crystalline porous material, composed of metal ions and multi dentate organic ligands with well-defined co-ordination geometry exhibiting promising application respect to adsorptive evacuation of OPs for chromatographic analysis. Applications of MOFs as preconcentration material and column packing material are reviewed. Key analytical characteristics of MOF based preconcentration techniques and coupled chromatographic procedures are summarized in detail. MOF based preconcentration strategies are compared with conventional sorbent based extraction techniques for thorough evaluation of performance of MOF materials.

Biogenic Silver Nanoparticles for Trace Colorimetric Sensing of Enzyme Disrupter Fungicide Vinclozolin

We report a novel, simple, efficient, and green protocol for biogenic synthesis of silver nanoparticles (AgNPs) in aqueous solution using clove (Syzygium aromaticum) extract as a reducing and protecting agent. Ultraviolet-visible (UV-Vis) spectroscopy was employed to monitor the localized surface plasmon resonance (LSPR) band of clove extract-derived AgNPs prepared under various conditions. Fourier-transform infrared (FTIR) spectroscopy analysis provided information about the surface interaction of the clove extract with the AgNPs. Ultrahigh-resolution transmission electron microscopy (UHRTEM) results confirmed the formation of spherical, uniformly distributed clove extract-capped AgNPs with sizes in the range of 2–20 nm (average size: 14.4 ± 2 nm). Powder X-ray diffractometry analysis (PXRD) illustrated the formation of pure crystalline AgNPs. These AgNPs were tested as a colorimetric sensor to detect trace amounts of vinclozolin (VIN) by UV-Vis spectroscopy for the first time. The AgNP-based sensor demonstrated very sensitive and selective colorimetric detection of VIN, in the range of 2–16 µM (R² = 0.997). The developed sensor was green, simple, sensitive, selective, economical, and novel, and could detect trace amounts of VIN with limit of detection (LOD) = 21 nM. Importantly, the sensor was successfully employed for the determination of VIN in real water samples collected from various areas in Turkey.

Removal of pesticides from white and red wines by microfiltration

The aim of this work is the investigation of microfiltration in removing pesticides from a white and a red Greek wine. Six membranes with pore size 0.45μm were investigated. Two mixtures of 23 and 9 pesticides, and single pesticide solutions were added in the wine. The pesticides tested belong to 11 chemical groups. Solid phase extraction (SPE) followed by gas chromatography (GC) with electron capture detector (ECD) were performed to analyze pesticide residues of the filtered fortified wine. Distinct behavior was exhibited by each membrane. Cellulose acetate and cellulose nitrate showed higher mean pesticide removal for both wines, followed by polyethersulfone, regenerated cellulose, and polyamides. The filtration effectiveness was correlated to the membrane type and to the pesticide chemical structure and properties (octanol-water partition coefficient, water solubility) and compared for the wines tested. In most cases, the more hydrophobic pesticides (pyrethroids and aldrin) showed higher removal from red wine than white wine. Adsorption on membranes was increased by increasing hydrophobicity and decreasing hydrophilicity of organic pesticide molecule. The removal of each pesticide from its single solution was generally higher than that from its mixtures, allowing the estimation of the antagonistic and synergistic effects of pesticides in the mixtures.

Evaluation of QuEChERS sample preparation and liquid chromatography-triple-quadrupole mass spectrometry method for the determination of 109 pesticide residues in tomatoes

A multiresidue method based on modified QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of 109 selected multiclass pesticides in tomatoes. The recovery yields ranged from 77.1% to 113.2%, with repeatabilities of 4.4-19.2% and within-laboratory reproducibilities of 7.1-18.4%. The limit of detections (LODs) for target analytes in tomato extract were between 0.5 and 10.8μgkg(-1), and the limit of quantifications (LOQs) were between 1.3 and 30.4μgkg(-1). The expanded measurement uncertainty was not higher than 30% for all target analytes. The method has been successfully applied to the analysis of 345 tomato samples obtained from local markets and tomato traders. Residues of acetamiprid, azoxystrobin and triadimefon were identified and measured in 9.6% of tomato samples, ranging from 0.015 to 0.37mgkg(-1).

Dispersive liquid-liquid microextraction combined with online preconcentration MEKC for the determination of some phenoxyacetic acids in drinking water

A fast and simple technique composed of dispersive liquid-liquid microextraction (DLLME) and online preconcentration MEKC with diode array detection was developed for the determination of four phenoxyacetic acids, 2,4,5-trichlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, 2,6-dichlorophenoxyacetic acid, and 4-chlorophenoxyacetic acid, in drinking water. The four phenoxyacetic acids were separated in reversed-migration MEKC to the baseline. About 145-fold increases in detection sensitivity were observed with online concentration strategy, compared with standard hydrodynamic injection (5 s at 25 mbar pressure). LODs ranged from 0.002 to 0.005 mg/L using only the online preconcentration procedures without any offline concentration of the extract. A DLLME procedure was used in combination with the proposed online preconcentration strategies, which achieved the determination of analytes at limits of quantification ranging from 0.2 to 0.5 μg/kg, which is far lower than the maximum residue limits established by China. The satisfactory recoveries obtained by DLMME spiked at two levels ranged from 67.2 to 99.4% with RSD <15%, making this proposed method suitable for the determination of phenoxyacetic acids in water samples.

Preparation and characterization of sodium dodecyl sulfate doped polypyrrole solid phase micro extraction fiber and its application to endocrine disruptor pesticide analysis

A robust in house solid-phase micro extraction (SPME) surface has been developed for the headspace (HS)-SPME determination of endocrine disruptor pesticides, namely, Chlorpyrifos, Penconazole, Procymidone, Bromopropylate and Lambda-Cyhalothrin in wine sample by using sodium dodecylsulfate doped polypyrrole SPME fiber. Pyrrole monomer was electrochemically polymerized on a stainless steel wire in laboratory conditions in virtue of diminishing the cost and enhancing the analyte retention on its surface to exert better selectivity and hence the developed polymerized surface could offer to analyst to exploit it as a fiber in headspace SPME analysis. The parameters, mainly, adsorption temperature and time, desorption temperature, stirring rate and salt amount were optimized to be as 70°C and 45min, 200°C, 600rpm and 10gL(-1), respectively. Limit of detection was estimated in the range of 0.073-1.659ngmL(-1) for the pesticides studied. The developed method was applied in to red wine sample with acceptable recovery values (92-107%) which were obtained for these selected pesticides.

Comparison of the selectivity of different sorbent phases for bar adsorptive microextraction--application to trace level analysis of fungicides in real matrices

Bar adsorptive micro-extraction combined with liquid desorption followed by large volume injection-gas chromatography-mass spectrometry operating in the selected-ion monitoring acquisition mode (BAμE-LD/LVI-GC-MS(SIM)) was developed for the determination of trace levels of ten fungicides (azoxystrobin, difenoconazole, metalaxyl-M, myclobutanil, penconazole, tebuconazole, flusilazole, cyprodinil, procymidone and benalaxyl) in aqueous matrices. By comparing different sorbent coatings (two activated carbons, two styrene-divinylbenzene and one modified pyrrolidone polymers) through BAμE, the latter phase showed much higher selectivity and capacity offering multiple mechanisms of interaction, even against polydimethylsiloxane by stir bar sorptive extraction. Assays performed on 25 mL of water samples spiked at the 0.8 μg/L level, yielded recoveries ranging from 100.0 to 107.8%, under optimized experimental conditions; BAμE(modified pyrrolidone) - equilibrium time: 4h (1000 rpm), pH 5.5; LD - solvent:methanol/acetonitrile (1/1), 15 min with sonification. The analytical performance showed convenient detection limits (4.0-30.0 ng/L) and excellent linear dynamic ranges (0.04-1.60 μg/L) with remarkable correlation coefficients (r(2)>0.9980). Excellent repeatability was also achieved through intraday (RSD<13.7%) and interday (RSD<9.9%) assays. By using the standard addition methodology, the application of the present analytical approach on tap and ground water, as well as, wine samples revealed good sensitivity and absence of matrix effects. The proposed method operating under floating sampling technology proved to be a suitable sorption-based static microextraction alternative to monitor fungicides in real matrices, showing to be easy to implement, reliable, sensitive, requiring low sample volume and the possibility to choose the most selective sorbent coating according to the targets of interest.

Determination of 24 pesticide residues in fortified wines by solid-phase microextraction and gas chromatography-tandem mass spectrometry

The present work describes a solid-phase microextraction (SPME) gas chromatography-tandem mass spectrometry (MS/MS) method to quantify 24 pesticides in fortified white wine and fortified red wine. In this study "fortified wine" refers to a wine in which fermentation is arrested before completion by alcohol distillate addition, allowing sugar and alcoholic contents to be higher (around 80-100 g/L total sugars and 19-22% alcohol strength (v/v)). The analytical method showed good linearity, presenting correlation coefficients (R(2)) ≥ 0.989 for all compounds. Limits of detection (LOD) and quantitation (LOQ) in the ranges of 0.05-72.35 and 0.16-219.23 μg/L, respectively, were obtained. LOQs are below the maximum residue levels (MRL) set by European Regulation for grapes. The proposed method was applied to 17 commercial fortified wines. The analyzed pesticides were not detected in the wines tested.

Determination of iprodione in agrochemicals by infrared and Raman spectrometry

Two methodologies based on vibrational spectrometry--making use of Fourier transform infrared absorption (FTIR) and Raman spectrometry--were developed for iprodione determination in solid pesticide formulations. The FTIR procedure involved the extraction of iprodione by CHCl(3), and the latter determination involved measuring the peak area between 1450 and 1440 cm(-1), corrected using a horizontal baseline defined at 1481 cm(-1). FT-Raman determination was performed directly on the powdered solid products, using standard chromatography glass vials as sample cells and measuring the Raman intensity between 1003 and 993 cm(-1), with a two-point baseline correction established between 1012 and 981 cm(-1). The sensitivities obtained were 0.319 area values g mg(-1) for FTIR determination and 5.58 area values g g(-1) for FT-Raman. The repeatabilities, taken to be the relative standard deviation of five independent measurements at 1.51 mg g(-1) and 10.98% w/w concentration levels, were equal to 0.16% and 0.9% for FTIR and FT-Raman, respectively, and the limits of detection were 0.3 and 0.2% w/w (higher than those obtained for HPLC, 0.016% w/w). FTIR determination provided a sample frequency of 60 h(-1), higher than those obtained for the Raman and reference chromatography methods (25 and 8.6 h(-1), respectively). On the other hand, the new FT-Raman method eliminates reagent consumption and waste generation, and reduces the need for sample handling and the contact of operator with the pesticide. In spite of their lack of sensitivity, vibrational procedures can therefore provide viable environmentally friendly alternatives to laborious, time- and solvent-consuming reference chromatography methods for quality control in commercially available pesticide formulations.

Characterization of the aroma profile of Madeira wine by sorptive extraction techniques

The characterization of the aroma profile of 33 samples of Madeira wine from five monovarieties (Sercial, Verdelho, Boal, Malvasia and Tinta Negra Mole) having different type and categories is presented, using solid phase microextraction and stir bar sorptive extraction techniques (SPME and SBSE) followed by capillary gas chromatography and mass spectrometry detection (GC-MS). Headspace SPME/GC-MS provided effectiveness to identify the major constituents of the aroma profile of Madeira wine, where no remarkable differences occur among the samples studied. The volatile compounds are mainly constituted by ethyl octanoate (11.3-256.9μgL^-1), ethyl decanoate (21.5-210.5μgL^-1), ethyl decenoate (0.1-112.8μgL^-1), diethyl succinate (0.9-65.6μgL^-1), ethyl dodecanoate (1.2-6.5μgL^-1), ethyl nonanoate (0.6-5.2μgL^-1), ethyl hexanoate (0.2-3.7μgL^-1) and isoamyl octanoate (0-2.2μgL^-1). C₁₃ norisoprenoids such as vitispirane (0.9-7.0μgL^-1) and 1,1,6-trimethyl 1,2-dihydro naphthalene (0.7-12.5μgL^-1), as well as phenyl ethanol (0-8.1μgL^-1), were also found in Madeira wine samples. The powerful capabilities of SBSE followed thermal desorption and GC-MS analysis allowed higher ability for profiling traces and ultra traces of compounds in Madeira wine samples, including esters (80.7-89.7%), carboxylic acids (1.6-4.2%), alcohols (3.5-8.2%), aldehydes (0.9-3.7%), pyrans (0.2-1.7%), lactones (<3%), monoterpenes (0.1-1.4%), sesquiterpenes (0.1-0.8%) and C₁₃ norisoprenoids (1.7-6.5%), which some of them play a remarkable impact on the aroma complexity. C₁₃ norisoprenoids in particular, seem to play an important role on Madeira wine bouquet since presenting very low sensorial threshold limits. Excellent correlation between Madeira wine ageing and the abundance of cis-oak lactone was attained showing to be an important chemical descriptor to characterize reserves and Vintages as well as a contributor to wine flavour. The differentiation between reserves, dry/medium dry and sweet/medium sweet young wines could be well established by means of chemometric analysis, using particular aroma compounds such as diethyl succinate, cis-oak lactone and ethyl octanoate as discriminating variables.

Determination of pesticides in red wines with on-line coupled microporous membrane liquid–liquid extraction-gas chromatography

Microporous membrane liquid-liquid extraction (MMLLE) was coupled on-line with gas chromatography for the determination of pesticides in wine. The MMLLE-GC provided to be efficient and selective and the method was linear, repeatable and sensitive. The limits of detection ranged from 0.05 to 2.3 microg/l and the limits of quantification were 0.2-7.5 microg/l for all the analytes using FID as detector. With MS detection LODs in the range 0.03-0.4 and LOQs of 0.3-3.5 microg/l were achieved. The method was applied to the determination of pesticides in several red wines of different origin.

Determination of pesticide residues in wine using gas chromatography with nitrogen-phosphorus and electron capture detection

A multiresidue method employing an extraction step with ethyl acetate followed by clean-up using an Isolute silica column and determination using gas chromatography with nitrogen-phosphorus and electron capture detection was validated for a wide range of pesticide residues in white and red wine. Recoveries between 70 and 110% and relative standard deviations below 20% were obtained for nearly all target analytes using matrix-matched standards. Limits of detection based on three times the signal-to-noise ratio were in the range 0.002-0.01 mg l(-1) for most compounds. The chromatograms were generally free of interference peaks resulting from co-extractives, although a few were noted for red wine with nitrogen-phosphorus detection. Ninety-two wine samples collected in Greece and Yugoslavia during 2 consecutive years were screened for residues of 84 pesticides, 71% of which were registered for use on vines in one or both countries. A total of 20% of the samples were obtained from field trials, and of these, one Greek wine contained iprodione 0.3 mg l(-1) and six Yugoslavian wines, for which vinclozolin had been added to the must as part of a different study, contained residues of this pesticide. No residues were detected in any of the other samples.

Coupling solid-phase microextraction and high-performance liquid chromatography for direct and sensitive determination of halogenated fungicides in wine

A solid-phase microextraction (SPME) method coupled to high-performance liquid chromatography with diode array detection (HPLC-DAD) for the analysis of six organochlorine fungicides (nuarimol, triadimenol, triadimefon, folpet, vinclozolin and penconazole) in wine was developed. For this purpose, polydimethylsiloxane-divinylbenzene-coated fibers were utilized and all factors affecting throughput, precision, and accuracy of the SPME method were investigated and optimized. These factors include: matrix influence, extraction and desorption time, percentage of ethanol, pH, salt effect and desorption mode. The performed analytical procedure showed detectability ranging from 4 to 27 microg l(-1) and precision from 2.4 to 14.2% (as intra-day relative standard deviation, RSD) and 4.7-25.7% (as inter-day RSD) depending on the fungicide. The results demonstrate the suitability of the SPME-HPLC-DAD method to analyze these organochlorine fungicides in red wine.

Evaluation of headspace solid-phase microextraction for the analysis of volatile carbonyl compounds in spirits and alcoholic beverages

A method was developed for the determination of C1-C6 carbonyl compounds in alcoholic solutions using pentafluorobenzoxymation followed by headspace sampling solid-phase microextraction and subsequent analysis by GC with electron-capture detection. Experimental conditions-alcohol content, exposure time, temperature and sample agitation were optimised. In this method, a spirit or distilled alcoholic beverage is first adjusted to 20% (v/v) alcohol. Detection limits for particular aldehydes and ketone varied from 0.05 to 0.5 microg/l and relative standard deviation was between 2.3 and 20%. Generally, the method showed good linearity for the tested concentration range 8 microg/l-0.32 mg/l with regression coefficients ranging between 0.9434 and 0.9983. The method was applied to the analysis of real alcoholic beverages (vodkas).