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1.
Sci Rep ; 14(1): 13064, 2024 06 06.
Article in English | MEDLINE | ID: mdl-38844596

ABSTRACT

This study aimed to investigate carbamate pesticide residues in different varieties of date palm fruits in the UAE, utilizing UHPLC-MS/MS. For sample preparation and clean-up, the efficiency and performance of different QuEChERS dispersive solid-phase extraction kits were compared. Precision and recovery were assessed at 10 µg kg-1 for the three kits, revealing that Kit 2 demonstrated the best performance. The selected QuEChERS method was validated to detect 14 carbamate residues in 55 date samples. The method exhibited strong linearity with R2 > 0.999 and low LOD (0.01-0.005 µg kg-1) and LOQ (0.003-0.04 µg kg-1). Excellent accuracy (recovery: 88-106%) and precision (RSD: 1-11%) were observed, with negligible matrix effect (- 4.98-13.26%). All samples contained at least one carbamate residue. While most detected residues were below their MRLs, carbosulfan was found in 21 samples, propoxur in 2 samples, and carbofuran in 1 sample above their MRLs. The hazard index (HI) was calculated for carbosulfan, phenmedipham, carbaryl, propoxur, carbofuran, and methomyl to assess potential health risks for date consumers. All HI values were below the safety limit of 1.0, indicating that the consumption of dates does not pose a non-carcinogenic health risk for adults and children.


Subject(s)
Carbamates , Fruit , Pesticide Residues , Phoeniceae , Tandem Mass Spectrometry , Phoeniceae/chemistry , Pesticide Residues/analysis , Chromatography, High Pressure Liquid/methods , Tandem Mass Spectrometry/methods , Carbamates/analysis , Fruit/chemistry , Humans , Risk Assessment , Solid Phase Extraction/methods , Food Contamination/analysis
2.
Sci Rep ; 14(1): 10293, 2024 05 04.
Article in English | MEDLINE | ID: mdl-38704412

ABSTRACT

In this study, a sensitive and selective fluorescent chemosensor was developed for the determination of pirimicarb pesticide by adopting the surface molecular imprinting approach. The magnetic molecularly imprinted polymer (MIP) nanocomposite was prepared using pirimicarb as the template molecule, CuFe2O4 nanoparticles, and graphene quantum dots as a fluorophore (MIP-CuFe2O4/GQDs). It was then characterized using X-ray diffraction (XRD) technique, Fourier transforms infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The response surface methodology (RSM) was also employed to optimize and estimate the effective parameters of pirimicarb adsorption by this polymer. According to the experimental results, the average particle size and imprinting factor (IF) of this polymer are 53.61 nm and 2.48, respectively. Moreover, this polymer has an excellent ability to adsorb pirimicarb with a removal percentage of 99.92 at pH = 7.54, initial pirimicarb concentration = 10.17 mg/L, polymer dosage = 840 mg/L, and contact time = 6.15 min. The detection of pirimicarb was performed by fluorescence spectroscopy at a concentration range of 0-50 mg/L, and a sensitivity of 15.808 a.u/mg and a limit of detection of 1.79 mg/L were obtained. Real samples with RSD less than 2 were measured using this chemosensor. Besides, the proposed chemosensor demonstrated remarkable selectivity by checking some other insecticides with similar and different molecular structures to pirimicarb, such as diazinon, deltamethrin, and chlorpyrifos.


Subject(s)
Pesticides , Pyrimidines , Pesticides/analysis , Carbamates/analysis , Carbamates/chemistry , Quantum Dots/chemistry , Molecularly Imprinted Polymers/chemistry , Polymers/chemistry , Spectrometry, Fluorescence/methods , Graphite/chemistry , Molecular Imprinting/methods , Adsorption , Limit of Detection , Spectroscopy, Fourier Transform Infrared , Nanocomposites/chemistry , Nanocomposites/ultrastructure
3.
Mikrochim Acta ; 191(6): 348, 2024 05 28.
Article in English | MEDLINE | ID: mdl-38805077

ABSTRACT

A novel aptamer-based sensor was developed using the signal amplification strategy of ring-opening metathesis polymerization (ROMP) and polyethyleneimine modified graphene oxide to achieve trace detection of carbendazim (CBZ). The dual identification of aptamer and antibody was used to avoid false positive results and improve the selectivity. Polyethyleneimine modified graphene oxide (GO-PEI), as a substrate material with excellent conductivity, was modified on the surface of a glassy carbon electrode (GCE) to increase the grafting amount of aptamer on the electrode surface. Moreover, a large number of cyclopentenyl ferrocene (CFc) was aggregated to form long polymer chains through ring-opening metathesis polymerization (ROMP), so as to significantly improve the detection sensitivity of the biosensor. The linear range of this sensor was 1 pg/mL-100 ng/mL with a detection limit as low as 7.80 fg/mL. The sensor exhibited excellent reproducibility and stability, and also achieved satisfactory results in actual sample detection. The design principle of such a sensor could provide innovative ideas for sensors in the detection of other types of targets.


Subject(s)
Aptamers, Nucleotide , Benzimidazoles , Biosensing Techniques , Carbamates , Electrochemical Techniques , Graphite , Limit of Detection , Polyethyleneimine , Polymerization , Graphite/chemistry , Carbamates/chemistry , Carbamates/analysis , Electrochemical Techniques/methods , Electrochemical Techniques/instrumentation , Polyethyleneimine/chemistry , Biosensing Techniques/methods , Benzimidazoles/chemistry , Aptamers, Nucleotide/chemistry , Electrodes , Reproducibility of Results
4.
Chemosphere ; 357: 142075, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38648985

ABSTRACT

Pesticides are considered one of the main sources of contamination of surface waters, especially in rural areas highly influenced by traditional agricultural practices. The objective of this work was to evaluate the impact caused by pesticides and their transformation products (TPs) related to olive groves in surface waters with strong agricultural pressure. 11 streams were monitored during four sampling campaigns over 2 years. A solid-phase extraction, followed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) analysis was used in the quantitative target approach, with more than 70 validated compounds. Target method was combined with a suspect screening strategy involving more than 500 pesticides and TPs, using ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) to identify additional pesticides and TPs out of the scope of analysis. A total of 43 different compounds were detected with the target method. The herbicide MCPA was present in all samples and at the highest concentration (1260 ng L-1), followed by the fungicide carbendazim (1110 ng L-1), and the herbicide chlorotoluron (706 ng L-1). The suspect screening strategy revealed the presence of 7 compounds out of the target analysis (1 pesticide and 6 TPs). 6 analytes were confirmed with the analytical standards. Semi-quantification results revealed that TPs exhibited higher concentrations than their corresponding parent compounds, indicating higher persistency. Some small streams showed a comparable number of pesticides and concentrations to the most polluted large river. The determined pesticide and TPs concentrations represented an estimated environmental hazard in almost all sampling sites under study. This work underscores the importance of including pesticide TPs and small streams impacted by extensive agricultural activities in water quality monitoring programs.


Subject(s)
Agriculture , Environmental Monitoring , Olea , Pesticides , Rivers , Tandem Mass Spectrometry , Water Pollutants, Chemical , Rivers/chemistry , Water Pollutants, Chemical/analysis , Pesticides/analysis , Risk Assessment , Olea/chemistry , Solid Phase Extraction , Carbamates/analysis , Chromatography, High Pressure Liquid , Herbicides/analysis , Benzimidazoles/analysis , Phenylurea Compounds
5.
Food Chem ; 450: 139260, 2024 Aug 30.
Article in English | MEDLINE | ID: mdl-38626714

ABSTRACT

High fluorescence intensity microspheres such as aggregation-induced emission fluorescence microspheres (AIEFM) have improved the sensitivity of lateral flow immunoassay (LFIA). The preparation of immune probes in LFIA usually adopts the chemical coupling strategy with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide for antibody coupling, which has the problems of low coupling efficiency, tedious coupling process, and poor repeatability. A biocompatible metal-phenolic network (MPN), which contains large amounts of phenols and galloyl groups, could easily, quickly, and stably couple with antibodies. Herein, we proposed a strategy based on MPN modification on ultrabright AIEFM surface as a novel label for the rapid detection of carbendazim. The limit of detection of AIEFM@MPN-LFIA was 0.019 ng/mL, which was 4.9 times lower than that of AIEFM-LFIA. In spiked samples, the average recoveries of AIEFM@MPN-LFIA ranged from 80% to 118% (coefficient of variation <13.45%). Therefore, AIEFM@MPN was a promising signal label that could improve the detection performance of LFIA.


Subject(s)
Benzimidazoles , Carbamates , Microspheres , Immunoassay/methods , Immunoassay/instrumentation , Benzimidazoles/chemistry , Benzimidazoles/analysis , Carbamates/analysis , Carbamates/chemistry , Phenols/analysis , Phenols/chemistry , Limit of Detection , Food Contamination/analysis , Fluorescence , Metals/chemistry , Fluorescent Dyes/chemistry , Biocompatible Materials/chemistry
6.
Environ Sci Pollut Res Int ; 31(19): 27749-27769, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38517634

ABSTRACT

Currently, pesticide production and use are on the rise globally. This trend is certain to continue in the coming decades with residues posing risks to the environment and human health even at low levels. Although various aspects of pesticides and their possible implications have widely been studied, such studies have mostly been carried out in developed countries leaving the rest of the world with little scientific information. We present here the results of a study on the occurrences, concentrations, and ecological risks of 30 pesticide residues (PRs) in water and sediment samples from a tropical freshwater Lake Hawassa in the Ethiopian Rift Valley. A total of 54 composite samples of water and sediment were collected from three sampling sites on three occasions. The samples were prepared by quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique, and analyzed using GC-MS at Bless Agri Food Laboratory Service located in Addis Ababa, Ethiopia. The study applied the risk quotient (RQ) method to scrutinize the risks posed to aquatic biota by the detected PRs. The results showed occurrences of 18 and 20 PRs in the water and sediment samples, respectively. The majority, 78 and 75% of the detected PRs in water and sediment samples, respectively represent the organochlorine chemical class. Concentrations of heptachlor epoxide were significantly (p ≤ 0.001) higher than those of the remaining pesticides in both matrices. Of the pesticides detected, 77% were present in water and 83% in sediment samples and pose a serious risk (RQ ≥ 1) to the Lake Hawassa biota. This calls for further research to investigate the risks to human health posed by the PRs. The findings of this study can contribute to the development of global protocols, as they support the concerns raised about the ecological and public health impacts of PRs on a global level.


Subject(s)
Environmental Monitoring , Hydrocarbons, Chlorinated , Lakes , Pesticide Residues , Water Pollutants, Chemical , Lakes/chemistry , Ethiopia , Pesticide Residues/analysis , Water Pollutants, Chemical/analysis , Hydrocarbons, Chlorinated/analysis , Carbamates/analysis , Organophosphorus Compounds/analysis , Risk Assessment , Pesticides/analysis
7.
J Dairy Sci ; 107(4): 1916-1927, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37923201

ABSTRACT

This study aimed to use ultra-high-performance liquid chromatography coupled to a triple-quadrupole mass spectrometer to detect 11 carbamate pesticide residues in raw and pasteurized camel milk samples collected from the United Arab Emirates. A method was developed and validated by evaluating limits of detection, limits of quantitation, linearity, extraction recovery, repeatability, intermediate precision, and matrix effect. Due to the high protein and fat content in camel milk, a sample preparation step was necessary to avoid potential interference during analysis. For this purpose, 5 different liquid-liquid extraction techniques were evaluated to determine their efficiency in extracting carbamate pesticides from camel milk. The established method demonstrated high accuracy and precision. The matrix effect for all carbamate pesticides was observed to fall within the soft range, indicating its negligible effect. Remarkably, detection limits for all carbamates were as low as 0.01 µg/kg. Additionally, the coefficients of determination were >0.998, demonstrating excellent linearity. A total of 17 camel milk samples were analyzed, and only one sample was found to be free from any carbamate residues. The remaining 16 samples contained at least one carbamate residue, yet all detected concentrations were below the recommended maximum residue limits set by Codex Alimentarius and the European Union pesticide databases. Nonetheless, it is worth noting that the detected levels of ethiofencarb in 3 samples were close to the borderline of the maximum residue limit. To assess the health risk for consumers of camel milk, the hazard index values of carbofuran, carbaryl, and propoxur were calculated. The hazard index values for these 3 carbamate pesticides were all below 1, indicating that camel milk consumers are not at risk from these residues.


Subject(s)
Pesticide Residues , Animals , Pesticide Residues/analysis , Tandem Mass Spectrometry/methods , Tandem Mass Spectrometry/veterinary , Camelus , Milk/chemistry , Chromatography, Liquid/methods , Chromatography, Liquid/veterinary , Chromatography, High Pressure Liquid/methods , Chromatography, High Pressure Liquid/veterinary , Carbamates/analysis , Risk Assessment
8.
Anal Methods ; 15(37): 4811-4826, 2023 09 28.
Article in English | MEDLINE | ID: mdl-37721714

ABSTRACT

Carbendazim is a broad-spectrum systemic fungicide that is used to control various fungal diseases in agriculture, horticulture, and forestry. Carbendazim is also used in post-harvest applications to prevent fungal growth on fruits and vegetables during storage and transportation. Carbendazim is regulated in many countries and banned in others, thus, there is a need for the sensing of carbendazim to ensure that high levels are avoided which can result in potential health risks. One approach is the use of electroanalytical sensors which present a rapid, but highly selective and sensitive output, whilst being economical and providing portable sensing platforms to support on-site analysis. In this minireview, we report on the electroanalytical sensing of carbendazim overviewing recent advances, helping to elucidate the electrochemical mechanism and provide conclusions and future perspectives of this field.


Subject(s)
Benzimidazoles , Carbamates , Benzimidazoles/analysis , Carbamates/analysis , Vegetables , Fruit/chemistry
9.
Environ Monit Assess ; 195(5): 626, 2023 Apr 29.
Article in English | MEDLINE | ID: mdl-37119335

ABSTRACT

This study provides comprehensive data on the seasonal variation and distribution of pesticides in the waters bordering Azagny National Park (ANP). Forty-six (46) samples of water from the Azagny area were analyzed using high-performance liquid chromatography (HPLC) coupled with a UV/visible detector to assess the level of thirty-one pesticide molecules divided into six families. These include triazines, phenylureas, organophosphates, carbamates, chloroacetanilides, dicarboximides, and crimidine, which are regularly used in this area. The respective average concentrations of pesticides are 54.54 µg//L, 20.93 µg/L, 18.24 µg/L, 3.06 µg/L, and 16.52 µg/L in the Bandama, Azagny Canal, ANP, mangroves, and estuarine environment. The analyses also showed that herbicides were the most abundant pesticides in the three waters, Bandama, Azagny Canal, and Azagny Park, with levels of 100%, 63%, and 59%, respectively, followed by insecticides with a levels of 0%, 37%, and 41%, respectively. However, rodenticides (76%) were more frequently detected than herbicides (24% in the mangroves). Regarding seasonal variation, high levels of pesticides were detected in the Bandama River, the Azagny Canal, and the mangroves during the dry season, while multiple pesticide residues were detected during the rainy season. The waters bordering Azagny National Park (ANP) are contaminated with pesticide residues (triazines, phenylureas, organophosphates, carbamates, and chloroacetanilides). As a result, policymakers should implement measures to regularly monitor pesticide levels in plantations surrounding the Azagny region's waters in order to better preserve biodiversity.


Subject(s)
Herbicides , Pesticide Residues , Pesticides , Water Pollutants, Chemical , Humans , Pesticides/analysis , Seasons , Pesticide Residues/analysis , Cote d'Ivoire , Environmental Monitoring , Water Pollutants, Chemical/analysis , Herbicides/analysis , Triazines/analysis , Carbamates/analysis
10.
Anal Sci ; 39(7): 1129-1142, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37000321

ABSTRACT

In the present work, a potential solid-phase extraction (SPE) material based on graphene anchored with platinum nanoparticles (Pt-Graphene) was prepared and characterized by scanning electron micrographs and transmission electron micrograph. The carbamates residues in fish were enriched by SPE filled with Pt-Graphene and detected by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The proposed extraction protocol exhibited satisfactory recoveries (76.5-115.6%), low limit of quantitation values in µg kg-1 level, and good precision for the studied ten carbamates. These results demonstrated the feasibility of the proposed protocol. The developed Pt-Graphene nanoparticles showed excellent performance for extracting analytes at trace levels, indicating that it could be used as a potential SPE sorbent in food residue analysis.


Subject(s)
Graphite , Metal Nanoparticles , Pesticides , Animals , Chromatography, Liquid/methods , Graphite/chemistry , Chromatography, High Pressure Liquid/methods , Tandem Mass Spectrometry/methods , Metal Nanoparticles/analysis , Platinum , Pesticides/analysis , Solid Phase Extraction/methods , Carbamates/analysis , Carbamates/chemistry
11.
Food Chem ; 410: 135429, 2023 Jun 01.
Article in English | MEDLINE | ID: mdl-36641915

ABSTRACT

Wearable sensors such as those made with paper are needed for non-destructive routine analysis of pesticides on plants, fruits, and vegetables. Herein we report on electrochemical sensors made with screen-printed carbon electrodes on kraft and parchment papers to detect the fungicide carbendazim. A systematic optimization was performed to find that electrochemical sensors on kraft paper treated in an acidic medium led to the highest performance, with a detection limit of 0.06 µM for carbendazim. The enhanced sensitivity for this sensor was attributed to the porous nature of kraft paper, which allowed for a large electrode surface area, and to the carboxylic groups formed during electrochemical activation. As a proof-of-concept, the electrochemical sensor attached to the skin of apple and cabbage was used to detect carbendazim with the same performance as the gold standard method, thus demonstrating that the sensor can be used in the farm and on supermarket shelves.


Subject(s)
Brassica , Malus , Limit of Detection , Carbamates/analysis , Electrochemical Techniques/methods , Electrodes
12.
J Chromatogr A ; 1689: 463744, 2023 Jan 25.
Article in English | MEDLINE | ID: mdl-36610187

ABSTRACT

In food safety monitoring, on-site and simultaneous detection of a variety of insecticides with different concentrations in the same matrix is necessary. However, the task remains challenging. In this study, a novel nitrogen and sulfur co-doped carbon dot (N, S-CD) was synthesized and used as a QuEChERS clean-up reagent to reduce matrix interferences in the determination of insecticides in vegetables. In addition, a portable mass spectrometer (µ-MS) was employed, without chromatography separation, to directly determine neonicotinoids, carbamates, and benzopyrazole insecticides (with acetamiprid, imidacloprid, thiamethoxam, fipronil, and carbofuran as models) in the pretreated samples. The N,S-CD µ-MS method exhibited effective clean-up performance with satisfactory matrix effects between -15.2% and 15.7%. The recoveries of spiked vegetable samples ranged from 82.2% to 109.7% for the five target insecticides, and the relative standard deviations (RSDs) ranged from 3.8% to 16.5%. The linear ranges were from 2.0 to 5.0 ng/g, with low detection limits (LOD) from 0.5 to 1.0 ng/g. Moreover, the total pretreatment and detection time was within 20 min. Thus, the incorporation of N,S-CD with QuEChERS extraction, together with the portable µ-MS system, could be a promising and feasible strategy for on-site, rapid, and simultaneous detection of various insecticides in vegetables.


Subject(s)
Insecticides , Pesticide Residues , Insecticides/analysis , Vegetables/chemistry , Carbamates/analysis , Tandem Mass Spectrometry/methods , Neonicotinoids/analysis , Pyrazoles , Pesticide Residues/analysis , Chromatography, High Pressure Liquid/methods
13.
Anal Methods ; 14(45): 4659-4668, 2022 11 24.
Article in English | MEDLINE | ID: mdl-36342027

ABSTRACT

Zeolitic imidazolate framework-8 modified magnetic halloysite nanotube (MHNTs@ZIF-8) composites were synthesized and evaluated for the first time as an efficient sorbent for the magnetic solid-phase extraction (mSPE) of carbamate pesticides (CPs) from water samples. MHNTs were prepared by coprecipitation, and MHNTs@ZIF-8 composites were assembled in situ at room temperature. After characterization, MHNTs@ZIF-8 was used to extract pirimicarb, propoxur, carbaryl, isoprocarb and fenobucarb via π-π stacking interaction and hydrophobic interaction between the imidazole skeleton of ZIF-8 and benzene rings or benzene-like rings in CPs, as well as the hydrogen bond formed between O in CPs and H in ZIF-8. The effects of the amount of sorbent, ionic strength, type and volume of desorption solvent and adsorption/desorption time were investigated. Under optimum conditions, good linearity was obtained for the analysis of CPs by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with R2 ≥ 0.9992. The limits of quantification range from 3 to 40 ng L-1 in water. Relative standard deviations (RSDs) were <7%, n = 5, within a batch and <9% among batches. The spiked recoveries were between 81 and 104%. The proposed method has been successfully applied to the determination of CPs in various water samples.


Subject(s)
Nanotubes , Pesticides , Water Pollutants, Chemical , Zeolites , Chromatography, High Pressure Liquid/methods , Zeolites/chemistry , Tandem Mass Spectrometry/methods , Clay , Benzene/analysis , Water Pollutants, Chemical/analysis , Solid Phase Extraction/methods , Pesticides/analysis , Carbamates/analysis , Esters , Nanotubes/analysis , Water/analysis , Magnetic Phenomena
14.
Chemosphere ; 309(Pt 1): 136725, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36208804

ABSTRACT

Simultaneous multiresidual pesticide analysis of saliva samples was performed using scaled-down QuEChERS extraction with LC-MS/MS and GC-MS/MS. The optimum extraction procedure using acidified acetonitrile was applicable to 336 pesticides (287 for LC-MS/MS and 49 for GC-MS/MS). To determine pesticide multiresidues in saliva, 100 µL of the sample was extracted with 200 µL of 0.1% formic acid in acetonitrile, and the initial extract was partitioned with 40 mg of MgSO4 and 10 mg of NaCl. The organic supernatants (120 µL) were then mixed with acetonitrile (30 µL) for matrix-matching (4:1, v/v), and the final extract solution was injected into the LC-MS/MS (4 µL) and GC-MS/MS (2 µL) systems. The established analytical method showed a good LOQs between 5 and 25 ng/mL with reliable accuracy/precision values and recovery results (50-140%) for the target pesticides. Under the two different storage conditions, most of the analytes did not undergo chemical changes in the saliva samples, whereas some pesticides were more stable in freeze-thaw processes than those left at room temperature. Biomonitoring of farmers (ten mixers and ten sprayers) was successfully applied using the validated method, and two carbamates (fenobucarb and propamocarb) were determined at trace concentrations (12.5-675.0 ng/mL from 11 positively detected samples).


Subject(s)
Pesticide Residues , Pesticides , Humans , Pesticides/analysis , Chromatography, Liquid , Tandem Mass Spectrometry/methods , Pesticide Residues/analysis , Gas Chromatography-Mass Spectrometry/methods , Biological Monitoring , Farmers , Saliva/chemistry , Sodium Chloride/analysis , Acetonitriles/analysis , Carbamates/analysis , Plant Extracts/analysis
15.
Molecules ; 27(13)2022 Jun 30.
Article in English | MEDLINE | ID: mdl-35807472

ABSTRACT

The current detection method of carbendazim suffers from the disadvantages of complicated preprocessing and long cycle time. In order to solve the problem of rapid quantitative screening of finite contaminants, this article proposed a qualitative method based on characteristic peaks and a semi-quantitative method based on threshold to detect carbendazim in apple, and finally the method is evaluated by a validation system based on binary output. The results showed that the detection limit for carbendazim was 0.5 mg/kg, and the detection probability was 100% when the concentration was no less than 1 mg/kg. The semi-quantitative analysis method had a false positive rate of 0% and 5% at 0.5 mg/kg and 2.5 mg/kg, respectively. The results of method evaluation showed that when the added concentration was greater than 2.5 mg/kg, the qualitative detection method was consistent with the reference method. When the concentration was no less than 5 mg/kg, the semi-quantitative method is consistent between different labs. The semi-quantitative method proposed in this study can achieve the screening of finite contaminants in blind samples and simplify the test validation process through the detection probability model, which can meet the needs of rapid on-site detection and has a good application prospect.


Subject(s)
Fruit , Spectrum Analysis, Raman , Benzimidazoles/analysis , Carbamates/analysis , Fruit/chemistry , Spectrum Analysis, Raman/methods
16.
Article in English | MEDLINE | ID: mdl-35838327

ABSTRACT

A novel microfluidic metal grating integrated terahertz sensor has been designed, which is composed of a metal microstructure array-dielectric layer-metal layer, where the dielectric layer is the microfluidic channel carrying the analyte. By adjusting the structural parameters of the metal grating sensor, a highly confined electromagnetic field can be obtained in the microfluidic channel, thereby significantly enhancing the interaction between the analyte and the terahertz wave and improving the terahertz detection sensitivity. The metal grating described in this paper is composed of an array of square holes, which is manufactured using laser micromachining technology, so that the measurement method is simplified and improved. The results show that the addition of different concentrations of carbendazim solution resulted in a redshift of the overall spectrum, with the highest sensitivity reaching 8.773 GHz/mg L-1, which is about eight times more sensitive than the traditional terahertz transmission sensor. The relative error of using this method to determine carbendazim levels in orange juice samples was less than 5.3%. The terahertz time-domain spectroscopy technology combined with the metal grating integrated microfluidic sensor can improve the sensitivity of sample detection and realize the rapid detection and analysis of trace elements.


Subject(s)
Citrus sinensis , Terahertz Spectroscopy , Benzimidazoles , Carbamates/analysis , Metals , Microfluidics , Terahertz Spectroscopy/methods
17.
Anal Sci ; 38(10): 1359-1367, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35908131

ABSTRACT

A microfluidic paper-based analytical device (µ-PAD) is a promising new technology platform for the development of extremely low-cost sensing devices. However, it has low sensitivity that might not enable to measure maximum allowable concentration of various pollutants in the environment. In this study, a dispersive liquid-liquid microextraction (DLLME) was developed as a preconcentration method to enhance the sensitivity of the µ-PAD for trace analysis of selected pesticides. Four critical parameters (volume of n-hexane and acetone, extraction time, NaCl amount) that affect the efficiency of DLLME have been optimized using response surface methodology. An acceptable mean recovery of 79-97% and 83-93% was observed at 1 µg L-1 and 5 µg L-1 fortification level, respectively, with very good repeatability (2.2-6.01% RSD) and reproducibility (5.60-10.41% RSD). Very high enrichment factors ranging from 317 to 1471 were obtained. The limits of detection for the studied analytes were in the range of 0.18-0.41 µg L-1 which is much lower than the WHO limits of 5-50 µg L-1 for similar category of analytes. Therefore, by coupling DLLME with µ-PAD, a sensitivity that allows to detect environmental threat and also that surpassed most of the previous reports have been achieved in this study. This implies that the preconcentration step has a paramount contribution to address the sensitivity problem associated with µ-PAD.


Subject(s)
Liquid Phase Microextraction , Pesticides , Water Pollutants, Chemical , Acetone/analysis , Carbamates/analysis , Liquid Phase Microextraction/methods , Microfluidics , Organophosphates/analysis , Pesticides/analysis , Reproducibility of Results , Sodium Chloride , Water , Water Pollutants, Chemical/analysis
18.
J Sci Food Agric ; 102(15): 7072-7078, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35690892

ABSTRACT

BACKGROUND: Treatment by ozone water is an emerging technology for the degradation of pesticide residues in vegetables. The ozone dissolved in water generates hydroxyl radicals (· OH), which are highly effective in decomposing organic substances, such as malathion and carbosulfan. RESULTS: We found that washing pak choi with 2.0 mg L-1 ozone water for 30 min resulted in 58.3% and 38.2% degradation of the malathion and carbosulfan contents respectively, and the degradation rates of these pure pesticides were 83.0% and 66.3% respectively. In addition, the 'first + first'-order reaction kinetic model was found to predict the trend in the pesticide content during ozone water treatment. Based on investigations by gas chromatography-mass spectrometry combined with the structures of the pesticides, the by-products generated were identified. More specifically, the ozonation-based degradation of carbosulfan generated carbofuran and benzofuranol, whereas malathion produced succinic acid and phosphoric acid. Although some new harmful compounds were formed during degradation of the parent pesticides, these were only present in trace quantities and were transient intermediates that eventually disappeared during the reaction. CONCLUSION: Our results, therefore, indicate that ozone water treatment technology for pesticide residue degradation is worthy of popularization and application. © 2022 Society of Chemical Industry.


Subject(s)
Ozone , Pesticide Residues , Pesticides , Water Pollutants, Chemical , Water Purification , Ozone/chemistry , Malathion/analysis , Carbamates/analysis , Water Purification/methods , Pesticides/analysis , Pesticide Residues/analysis , Water Pollutants, Chemical/chemistry , Oxidation-Reduction
19.
Biosens Bioelectron ; 203: 114036, 2022 May 01.
Article in English | MEDLINE | ID: mdl-35134683

ABSTRACT

Carbendazim (CBZ) has been widely used in agricultural production to control fruits and vegetables diseases, but it can also destroy the human endocrine system. Therefore, sensitive detection of CBZ has attracted increasing attention worldwide. In this study, Pd nanoparticles (Pd NPs) decorated on CdS microsphere (Pd NPs/CdS) was prepared by the in-situ photoreduced method, and based on the surface plasmon resonance (SPR) effect of noble metal and Schottky junction between Pd nanoparticles (Pd NPs) and CdS microsphere, the photocurrent after introducing Pd NPs is 7.7 times higher than that of bare CdS microsphere. In view of the outstanding photoelectrochemical (PEC) performance of Pd NPs/CdS and the high specificity of the aptamer, the as-fabricated PEC aptasensor for CBZ detection possesses the excellent detection performance including a broad linear ranging from 1.0 × 10-12 to 1.0 × 10-6 mol/L as a low detection limit of 3.3 × 10-13 mol/L (S/N = 3). Furthermore, the PEC aptasensor was used for determination of lettuce samples from actual agricultural products with satisfactory results.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Metal Nanoparticles , Nanoparticles , Benzimidazoles/analysis , Biosensing Techniques/methods , Cadmium Compounds , Carbamates/analysis , Electrochemical Techniques/methods , Limit of Detection , Microspheres , Palladium , Sulfides
20.
J Agric Food Chem ; 70(7): 2127-2135, 2022 Feb 23.
Article in English | MEDLINE | ID: mdl-35138837

ABSTRACT

Fenobucarb (2-sec-butylphenyl methylcarbamate, BPMC) is a potent carbamate pesticide with high insecticidal activity. In this study, the enantioselective accumulation of BPMC in earthworms (Eisenia foetida) and dissipation in cabbage, Chinese cabbage, strawberry, and soils were investigated. The samples were prepared using the QuEChERS method and analyzed using fast and sensitive chiral high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis. The stereoselective accumulation of BPMC enantiomers revealed that S-(+)-BPMC was preferentially accumulated in earthworms rather than its antipode. However, the dissipation studies showed that S-(+)-BPMC degraded faster than the R-(-)-isomer in cabbage, Chinese cabbage, strawberry, and soils. Furthermore, the cytotoxic effect of BPMC enantiomers toward PC12 and N9 neuronal, A549 lung cancer, and MRC5 lung fibroblast cell lines was evaluated using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Compared with R-(-)- and rac-isomers, S-(+)-BPMC exhibited lower cytotoxicity in neuronal cells and a weaker proliferating effect on lung cancer and lung fibroblast cells. Altogether, the findings suggest the use of the pure S-(+)-enantiomer in agricultural management rather than the use of the racemate or the R-(-)-isomer, which might reduce the environmental risk.


Subject(s)
Oligochaeta , Soil Pollutants , Animals , Carbamates/analysis , Fruit/chemistry , Soil/chemistry , Soil Pollutants/chemistry , Stereoisomerism , Tandem Mass Spectrometry , Vegetables/chemistry
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