Associations of pyrethroid exposure with bone mineral density and osteopenia in adults.

INTRODUCTION: This study was to investigate the correlations between pyrethroid exposure and bone mineral density (BMD) and osteopenia. MATERIALS AND METHODS: This cross-sectional study included 1389 participants over 50 years of age drawn from the 2007-2010 and 2013-2014 National Health and Nutrition Examination Survey (NHANES). Three pyrethroid metabolites, 3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid (trans-DCCA), and 4-fluoro-3-phenoxybenzoic acid (4-F-3PBA) were used as indicators of pyrethroid exposure. Low BMD was defined as T-score < - 1.0, including osteopenia. Weighted multivariable linear regression analysis or logistic regression analysis was utilized to evaluate the correlation between pyrethroid exposure and BMD and low BMD. Bayesian kernel machine regression (BKMR) model was utilized to analyze the correlation between pyrethroids mixed exposure and low BMD. RESULTS: There were 648 (48.41%) patients with low BMD. In individual pyrethroid metabolite analysis, both tertile 2 and tertile 3 of trans-DCCA were negatively related to total femur, femur neck, and total spine BMD [coefficient (ß) = - 0.041 to - 0.028; all P < 0.05]. Both tertile 2 and tertile 3 of 4-F-3PBA were negatively related to total femur BMD (P < 0.05). Only tertile 2 [odds ratio (OR) = 1.63; 95% CI = 1.07, 2.48] and tertile 3 (OR = 1.65; 95% CI = 1.10, 2.50) of trans-DCCA was correlated with an increased risk of low BMD. The BKMR analysis indicated that there was a positive tendency between mixed pyrethroids exposure and low BMD. CONCLUSION: In conclusion, pyrethroids exposure was negatively correlated with BMD levels, and the associations of pyrethroids with BMD and low BMD varied by specific pyrethroids, pyrethroid concentrations, and bone sites.

Assessing human exposure to pesticides and mycotoxins: optimization and validation of a method for multianalyte determination in urine samples.

Humans are exposed to an increasing number of contaminants, with diet being one of the most important exposure routes. In this framework, human biomonitoring is considered the gold standard for evaluating human exposure to chemicals. Pesticides and mycotoxins are chemicals of special concern due to their health implications. They constitute the predominant border rejection notifications for food and feed in Europe and the USA. However, current biomonitoring studies are focused on a limited number of compounds and do not evaluate mycotoxins and pesticides together. In this study, an analytical method has been developed for the determination of 30 pesticides and 23 mycotoxins of concern in urine samples. A salting-out liquid-liquid extraction (SALLE) procedure was optimized achieving recoveries between 70 and 120% for almost all the compounds and limits as lower as when QuEChERS was applied. The compounds were then determined by liquid chromatography coupled to triple quadrupole mass spectrometry. Different chromatographic conditions and analytical columns were tested, selecting a Hypersild gold aQ column as the best option. Finally, the method was applied to the analysis of 45 urine samples, in which organophosphate and pyrethroid pesticides (detection rates (DR) of 82% and 42%, respectively) and ochratoxin A and deoxynivalenol (DR of 51% and 33%, respectively) were the most detected compounds. The proposed analytical method involves the simultaneous determination of a diverse set of pesticides and mycotoxins, including their most relevant metabolites, in human urine. It serves as an essential tool for biomonitoring the presence of highly prevalent contaminants in modern society.

Fates and models for exposure pathways of pyrethroid pesticide residues: A review.

Pyrethroids (PYs) are widely applied pesticides whose residues pose potential health risks. This review describes current knowledge on PY chemical properties, usage patterns, environmental and food contamination, and human exposure models. It evaluates life cycle assessment (LCA), chemical alternatives assessment (CAA), and high-throughput screening (HTS) as tools for pesticide policy. Despite efforts to mitigate PY presence, their pervasive residues in the environment and food persist. And the highest concentrations ranged from 54,360 to 80,500 ng/L in water samples from agricultural fields. Food processing techniques variably reduce PY levels, yet no method guarantees complete elimination. This review provides insights into the fates and exposure pathways of PY residues in agriculture and food, and highlights the necessity for improved PY management and alternative practices to safeguard health and environment.

COF-SiO2@Fe3O4 Composite for Magnetic Solid-Phase Extraction of Pyrethroid Pesticides in Vegetables.

Pyrethroid pesticides (PYRs) have found widespread application in agriculture for the protection of fruit and vegetable crops. Nonetheless, excessive usage or improper application may allow the residues to exceed the safe limits and pose a threat to consumer safety. Thus, there is an urgent need to develop efficient technologies for the elimination or trace detection of PYRs from vegetables. Here, a simple and efficient magnetic solid-phase extraction (MSPE) strategy was developed for the simultaneous purification and enrichment of five PYRs in vegetables, employing the magnetic covalent organic framework nanomaterial COF-SiO2@Fe3O4 as an adsorbent. COF-SiO2@Fe3O4 was prepared by a straightforward solvothermal method, using Fe3O4 as a magnetic core and benzidine and 3,3,5,5-tetraaldehyde biphenyl as the two building units. COF-SiO2@Fe3O4 could effectively capture the targeted PYRs by virtue of its abundant π-electron system and hydroxyl groups. The impact of various experimental parameters on the extraction efficiency was investigated to optimize the MSPE conditions, including the adsorbent amount, extraction time, elution solvent type and elution time. Subsequently, method validation was conducted under the optimal conditions in conjunction with gas chromatography-mass spectrometry (GC-MS). Within the range of 5.00-100 µg·kg-1 (1.00-100 µg·kg-1 for bifenthrin and 2.5-100 µg·kg-1 for fenpropathrin), the five PYRs exhibited a strong linear relationship, with determination coefficients ranging from 0.9990 to 0.9997. The limits of detection (LODs) were 0.3-1.5 µg·kg-1, and the limits of quantification (LOQs) were 0.9-4.5 µg·kg-1. The recoveries were 80.2-116.7% with relative standard deviations (RSDs) below 7.0%. Finally, COF-SiO2@Fe3O4, NH2-SiO2@Fe3O4 and Fe3O4 were compared as MSPE adsorbents for PYRs. The results indicated that COF-SiO2@Fe3O4 was an efficient and rapid selective adsorbent for PYRs. This method holds promise for the determination of PYRs in real samples.

Pesticide application behavior in green tea cultivation and risk assessment of tea products: a case study of Rizhao green tea.

Previous research on pesticides in green tea mainly focused on detection technology but lacked insights into pesticide use during cultivation. To address this gap, a survey was conducted among Rizhao green tea farmers. The survey results showed that most tea farmers were approximately 60 years old and managed small, scattered tea gardens (< 0.067 ha). Notably, tea farmers who had received agricultural training executed more standardized pesticide application practices. Matrine and thiazinone are the most used pesticides. A total of 16 types of pesticides were detected in the tested green tea samples, with 65% of the samples containing residues of at least one pesticide. Notably, higher levels of residues were observed for bifenthrin, cyfluthrin, and acetamiprid. The presence of pesticide residues varied significantly between seasons and regions. The risk assessment results indicated that the hazard quotient (HQ) values for all 16 pesticides detected in green tea were < 1, suggesting that these residue levels do not pose a significant public health concern.

Impairment of apoptosis pathway via Apaf1 downregulation during chlorpyrifos and/or cypermethrin induced lung damage.

Chlorpyrifos is an organophosphate and the cypermethrin is type 2 pyrethroid insecticide that are used for indoor and outdoor pest control. The present study aimed to investigate differential transcriptional profiling to identify the candidate gene associated with lung injury following exposure to chlorpyrifos and/or cypermethrin in a mouse model system. Swiss male albino mice (n = 24) were divided into three treatment groups (n = 6 each) that were given chlorpyrifos (2.76 mg kg-1 body weight), cypermethrin (2 mg kg-1 body weight) and the combination of both pesticides orally dissolved in corn oil and one control group (n = 6) that received corn oil for 90 days. The pulmonary expression of the Apaf1 was observed using RT2 Profiler PCR Array. The results showed that chronic exposure to chlorpyrifos, cypermethrin and their combination downregulated (67, 63 and 66 genes) and upregulated (4, 2 and 2 genes), respectively. The pulmonary expression of Apaf1 that plays important role in apoptosis was found to be downregulated. The immunohistochemistry depicted reduced expression of Apaf1 in both airway epithelium and alveolar septa following exposure to chlorpyrifos and/or cypermethrin. In conclusion, results demonstrated that exposure to chlorpyrifos, cypermethrin and their combination cause lung damage by the dysregulation of Apaf1 gene expression.

Assessment of Preschool Children's Exposure Levels to Organophosphate and Pyrethroid Pesticide: A Human Biomonitoring Study in Two Turkish Provinces.

Pesticides are products developed to prevent, destroy, repel or control certain forms of plant or animal life that are considered to be pests. However, now they are one of the critical risk factors threatening the environment, and they create a significant threat to the health of children. Organophosphate (OP) and pyrethroid (PYR) pesticides are widely used in Turkey as well as all over the world. The main focus of this presented study was to analyze the OP and PYR exposure levels in urine samples obtained from 3- to 6-year-old Turkish preschool children who live in the Ankara (n:132) and Mersin (n:54) provinces. In order to measure the concentrations of three nonspecific metabolites of PYR insecticides and four nonspecific and one specific metabolite of OPs, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses were performed. The nonspecific PYR metabolite 3-phenoxybenzoic acid (3-PBA) found in 87.1% of samples (n = 162) and the specific OP metabolite 3,5,6-trichloro-2-pyridinol (TCPY) found in 60.2% of samples (n = 112) were the most frequently detected metabolites in all urine samples. The mean concentrations of 3-PBA and TCPY were 0.38 ± 0.8 and 0.11 ± 0.43 ng/g creatinine, respectively. Although due to the large individual variation no statistically significant differences were found between 3-PBA (p = 0.9969) and TCPY (p = 0.6558) urine levels in the two provinces, significant exposure differences were determined both between provinces and within the province in terms of gender. Risk assessment strategies performed in light of our findings do not disclose any proof of a possible health problems related to analyzed pesticide exposure in Turkish children.

Residual Behavior and Dietary Risk Assessment of Chlorfenapyr and Its Metabolites in Radish.

Chlorfenapyr, as a highly effective and low-toxicity insect growth regulation inhibitor, has been used to control cross-cruciferous vegetable pests. However, the pesticide residue caused by its application threatens human health. In this paper, the residue digestion and final residue of chlorfenapyr in radish were studied in a field experiment. The results of the dynamic digestion test showed that the half-life of chlorfenapyr in radish leaves ranged from 6.0 to 6.4 days, and the digestion rate was fast. The median residual values of chlorfenapyr in radish and radish leaves at 14 days after treatment were 0.12 and 3.92 mg/kg, respectively. The results of the dietary intake risk assessment showed that the national estimated daily intake (NEDI) of chlorfenapyr in various populations in China were 0.373 and 5.66 µg/(kg bw·d), respectively. The risk entropy (RQ) was 0.012 and 0.147, respectively, indicating that the chronic dietary intake risk of chlorfenapyr in radish was low. The results of this study provided data support and a theoretical basis for guiding the scientific use of chlorfenapyr in radish production and evaluating the dietary risk of chlorfenapyr in vegetables.

Magnetic solid-phase extraction of pyrethroid and neonicotinoid insecticides separately in environmental water samples based on alkaline or acidic group-functionalized mesoporous silica.

Pyrethroids and neonicotinoids are widely used insecticides. However, their residues have unfavorable effects on ecological systems. Magnetic solid phase extraction is a reliable pretreatment method for a better detection of insecticides at low concentrations. In this work, amino- and carboxyl-functionalized magnetic KIT-6 were designed according to the electron-accepting groups of pyrethroid molecules and electron-donating groups with neonicotinoid structures. The characterization of these two materials was conducted using transmission electron microscopy, scanning electron microscopy, nitrogen adsorption-desorption analysis, etc. The aminated composite was applied to the magnetic solid phase extraction of pyrethroid insecticides while the carboxylic one was applied to neonicotinoids, and the adsorption effects were comprehensively compared for the first time. The material dosage, solution pH, and some factors that influenced the recovery were studied and optimized. The adsorption processes of the materials were all spontaneous and exothermic. They also fitted well with pseudo-second order kinetics and Langmuir adsorption isotherms. Both physical (pore function) and chemical (electrostatic interaction) adsorption mechanisms were present in the process. The two nanocomposites were then successfully used to enrich the two kinds of insecticides in environmental water samples. The proposed method has great application potential for insecticide monitoring in complex environmental samples.

Residual levels and dietary risk assessment of bifenthrin and dinotefuran and its major metabolites in open wheat field conditions.

To evaluate the residual levels of bifenthrin and dinotefuran, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) and high-performance liquid chromatography-tandem mass spectrometry method for simultaneous detection of bifenthrin and dinotefuran and its major metabolites in wheat was developed and validated. Dietary risk assessments were further performed based on the relevant residual data from 12 wheat fields, toxicology data and dietary patterns. In wheat grain and straw, the recoveries of all analytes ranged from 77 to 102% with the relative standard deviation <9.7% and the limit of quantitation 0.05 mg kg-1 . The highest terminal residue of bifenthrin in wheat grain was 0.069 mg kg-1 and dinotefuran was 0.34 mg kg-1 . Residual concentrations of bifenthrin and dinotefuran decreased to <0.05 and 0.15 mg kg-1 at 21 days (pre-harvest interval), respectively. The chronic risk quotient ranged from 6.4 to 62.7% and the acute risk quotient varied from 0.38 to 17.73%. The chronic and acute dietary risks caused by the terminal residues of the two insecticides were negligible for Chinese populations. The recommended pre-harvest interval was proposed to ensure safe wheat consumption. These data could provide a scientific reference to establish the Chinese maximum residue limit of dinotefuran in wheat.

Method Development and Validation of Seven Pyrethroid Insecticides in Tea and Vegetable by Modified QuEChERS and HPLC-MS/MS.

This study developed a quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure for determining seven pyrethroid pesticide residues in tea, cucumber, and tomato via high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The overall average recoveries of the seven pyrethroids were 72%-104% (relative standard deviation (RSD); 2.0%-16.1%, 89%-109% (RSD; 0.7%-17.3%), 82%-110% (RSD; 1.6%-17.1%) for tea, cucumber and tomato, respectively. The determination coefficient (R2), the limit of detection (LOD), and the limit of quantification (LOQ) were ≥ 0.99, 0.007-1.875 µg kg-1, and 0.025-6.250 µg kg-1, respectively. The method was successfully used to monitor the pyrethroid pesticide residues in market samples. HPLC-MS/MS rapidly, sensitively, and accurately determined the pyrethroid pesticide residues.

[Pesticide residues in Chinese medicinal materials and suggestions for safety].

The present study counted the frequency of detection technologies and monitoring frequency of pesticide species by frequency analysis based on the 28 258 pieces of data on pesticide content of Chinese medicinal materials in CNKI, calculated the detection rate and exceeding rate of different types of pesticides, and systematically analyzed the pesticide residue pollution of Chinese medicinal materials. The results showed that there were 40 types of pesticides with detection rates higher than 10%, where new pesticides such as organochlorines and nicotine accounted for 55%, and organic phosphorus, pyrethroids, and carbamates accounted for 17.5%, 15.0%, and 12.5%, respectively. Seventeen types of pesticides exceeded the standard to varying degrees, including 12 types(70.59%) with exceeding rates not higher than 5%, four types(23.53%) with exceeding rates in the range of 5%-10%, and one type(5.88%) with an exceeding rate higher than 10%. As revealed by the analysis results of the past five years, the pesticide residue pollution of Chinese medicinal materials showed a downward trend. Compared with the conditions at worst, organochlorines decreased by about 2/3 in detection rate and 47.23% in exceeding rate, carbamates by about 1/2 in detection rate and 10.78% in exceeding rate, organic phosphorus by 3/4 in detection rate and 7.22% in exceeding rate, pyrethroids by 1/2 in detection rate and 11.05% in exceeding rate, and other types by about 1/2 in detection rate but not exceeded the standard. In general, pesticide residues in Chinese medicinal materials and safety have been significantly improved. However, pesticide residues are still important factors affecting the quality and safety of Chinese medicinal materials. It is suggested to further improve the control standards of pesticide residues in Chinese medicinal materials, strengthen the monitoring of pesticides used in practical production, and promote the ecological planting mode to facilitate the high-quality development of the Chinese medicinal material industry.

Utilization of rGO-PEI-supported AgNPs for sensitive recognition of deltamethrin in human plasma samples: A new platform for the biomedical analysis of pesticides in human biofluids.

In this study, the rGO-PEI-AgNPs sensor was designed as a new effective platform to sensitive monitoring of deltamethrin in human plasma samples. For this purpose, reduced graphene oxide (rGO)-supported polyethylenimine (PEI) was used as a suitable substrate for dispersion of silver nanoparticles (AgNPs) as amplification and catalytic element. Therefore, a novel interface (rGO-PEI-AgNPs) was prepared by the fully electrochemical method on the surface of glassy carbon electrodes. The engineered nano-sensor showed a wide dynamic range of 10 nM to 1 mM and low limit of quantification (LLOQ) as 10 nM in human plasma sample, which revealed excellent analytical performance for the recognition of deltamethrin with high sensitivity and reproducibility through differential pulse voltammetry and square wave voltammetry techniques. The results confirm that rGO-PEI-AgNPs as a novel biocompatible interface can provide appropriate, reliable, affordable, rapid, and user-friendly diagnostic tools in the detection of deltamethrin in human real samples.

Automated Solid-Phase Microextraction and Negative Chemical Ionization GC-MS for the Measurement of Synthetic Pyrethroids.

Synthetic pyrethroids are frequently detected as trace contaminants in sediment and natural waters. Because of the importance of measuring both total and freely available concentrations for ecotoxicity evaluations, solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry using negative chemical ionization (NCI-GC-MS) was investigated as an analytical technique. Automated SPME-NCI-GC-MS quantification of freely dissolved (and thus potentially bioavailable) pyrethroids in aqueous samples containing dissolved organic matter (DOM) was successfully applied. The introduction of stable isotope-labeled pyrethroid calibration standards into the water sample allows for the simultaneous determination of total concentrations. Because pyrethroids adsorb rapidly to container walls (especially in calibration standard solutions without DOM) it was necessary to develop a technique to minimize the resulting time-dependent losses from calibration standard solutions in autosampler vials as they await analysis. A staggered preparation of these analytical calibration standards immediately prior to analysis was shown to ameliorate this problem. The developed method provides accurate and reproducible results for aqueous samples containing a range of dissolved organic matter concentrations (e.g., sediment pore water or sediment/water mixtures) and yields practical benefits in comparison to conventional analysis methods, such as reduced sample volume requirements, reduced solvent consumption, and fewer sample manipulations, and makes simultaneous measurements of freely dissolved/bioavailable pyrethroids and total pyrethroids possible.

A colorimetric test for the evaluation of the insecticide content of LLINs used on Bioko Island, Equatorial Guinea.

BACKGROUND: Insecticide-treated nets and indoor residual spraying of insecticides are used as the vector control interventions in the fight against malaria. Measuring the actual amount of deposits of insecticides on bed nets and walls is essential for evaluating the quality and effectiveness of the intervention. A colorimetric "Test Kit" designed for use as a screening tool, able to detect the type II pyrethroids on fabrics and sprayed walls, was used for the first time to detect deltamethrin on long-lasting insecticidal nets (LLINs) deployed on Bioko Island, Equatorial Guinea. METHODS: LLINs were analysed using the colorimetric Test Kit performed in situ, which leads to the formation of an orange-red solution whose depth of colour indicates the amount of type II pyrethroid on the net. The kit results were validated by measuring the amount of extracted insecticide using high-performance liquid chromatography (HPLC) with diode array detection (DAD). RESULTS: Deltamethrin concentration was determined for 130 LLINs by HPLC-DAD. The deltamethrin concentration of these nets exhibited a significant decrease with the age of the net from 65 mg/m2 (< 12 months of use) to 31 mg/m2 (> 48 months; p < 0.001). Overall, 18% of the nets being used in households had < 15 mg/m2 of deltamethrin, thus falling into the "Fail" category as assessed by the colorimetric Test Kit. This was supported by determining the bio-efficacy of the nets using the WHO recommended cone bioassays. The Test Kit was field evaluated in situ and found to be rapid, accurate, and easy to use by people without laboratory training. The Test Kit was shown to have a reliable linear relationship between the depth of colour produced and deltamethrin concentration (R2 = 0.9135). CONCLUSION: This study shows that this colorimetric test was a reliable method to assess the insecticidal content of LLINs under operational conditions. The Test Kit provides immediate results and offers a rapid, inexpensive, field-friendly alternative to the complicated and costly methods such as HPLC and WHO cone bioassays which also need specialist staff. Thus, enabling National Malaria Control Programmes to gain access to effective and affordable monitoring tools for use in situ.

Analysis of pesticide residues by a support vector machine combined with fluorescence spectroscopy.

Pesticide residues enter a lake through the water cycle, causing harm to the water environment and human health. It is necessary to select highly sensitive fluorescence spectroscopy to detect pesticides (bifenthrin, prochloraz, and cyromazine), and a support vector machine (SVM) is used to analyze the concentration of pesticides. In addition, this paper adopts K-fold cross validation and a grid search to optimize the SVM algorithm. The performance evaluation index and running time prove the reliability of the results of this experiment. They show that fluorescence spectroscopy combined with SVM is efficient in predicting pesticide residue content.

Identification of cattle poisoning by Bifenthrin via earwax analysis by HS/GC-MS.

The use of pyrethroids has increased over recent years, and corresponds to a higher exposure of animals to pesticide residues in the environment and diet. Here, an outbreak of pyrethroid poisoning in beef cattle was reported occurring in Midwestern Brazil. After veterinary evaluation, it was observed that the bovines presented common pyrethroid intoxication symptoms. Aiming to identify the cattle poising by pyrethroid, earwax samples were collected from two groups: exposed and nonexposed animals from the same farm. Blind earwax analyses of the bovines were carried out using headspace/gas chromatography-mass spectrometry (HS/GC-MS). The HS/GC-MS analysis detected the presence of bifenthrin in the earwax analysis of the exposed animals, confirmed by the comparison of its MS fragments with a bifenthrin standard, and also by its retention time relative to the internal standard. In summary, HS/GC-MS analysis of earwax emerges as a tool that can be used in the detection and monitoring of bifenthrin poisoning in cattle, as a useful veterinary diagnosis that ensures animal health and the safety of their products.

Dissipation kinetics and consumer risk assessment of novaluron + lambda-cyhalothrin co-formulation in cabbage.

Cabbage, one of the most popular vegetables in the world is infested by several insect-pests and diseases. Novaluron, a chitin synthesis inhibitor and lambda-cyhalothrin, a synthetic pyrethroid group insecticide are used to manage insect-pests on cabbage. The dissipation kinetics and risk assessment of combination formulation (novaluron 9.45% + lambda-cyhalothrin 1.9%) with different modes of action has not yet been investigated in cabbage. Multi-location supervised field trials were therefore, conducted in different agro-climatic regions of India for safety evaluation of the combination product. The co-formulation at the recommended (novaluron 750 g a.i. ha-1 + lambda-cyhalothrin 750 g a.i. ha-1) and double the recommended (novaluron 1500 g a.i. ha-1 + lambda-cyhalothrin 1500 g a.i. ha-1) dose was sprayed on the cabbage crop. The samples were extracted and cleaned up using a modified QuEChERS method, and the residues analyzed by GC-ECD and GC-MS. The half-life (t1/2) varied between 1.77 and 2.51 and 2.00-3.38 days for novaluron and 1.36-2.24 and 1.69-3.82 days for lambda-cyhalothrin in cabbage at respective doses. The Food Safety and Standards Authority of India (FSSAI) has set the MRL of 0.7 mg kg-1 for novaluron at PHI of 5 days, and no MRL is set for lambda-cyhalothrin in cabbage. On the basis of OECD MRL calculator, the MRLs of 0.6 and 1.5 mg kg-1 for novaluron and lambda-cyhalothrin, respectively were calculated at the respective doses at PHI of 3 days. Hazard quotient (HQ) <1, theoretical maximum daily intake (TMDI) < acceptable daily intake (ADI) and < maximum permissible intake (MPI), percent acute hazard index (% aHI) <1, and percent chronic hazard index (% cHI) <1 for both novaluron and lambda-cyhalothrin suggested that the combination formulation is safe and will not pose any dietary risk to the consumers. The study will be helpful to conduct risk assessment of other pesticides/combination pesticides on food crops on which their MRLs have not yet been fixed.

A multifunctional near-infrared fluorescent sensing material based on core-shell upconversion nanoparticles@magnetic nanoparticles and molecularly imprinted polymers for detection of deltamethrin.

The construction of multifunctional sensors has attracted considerable attention due to their multifunctional properties, such as high sensitivity and rapid detection. Herein, near-infrared multifunctional fluorescent sensing materials based on core-shell upconversion nanoparticle@magnetic nanoparticle and molecularly imprinted polymers were synthesized for rapid detection of deltamethrin. The difunctional core-shell upconversion nanoparticle@magnetic nanoparticle was introduced as the optical signal and rapid separator. Firstly, the difunctional core-shell materials were prepared through solvothermal method. Then, molecularly imprinted polymers (MIPs) as recognition elements for deltamethrin were coated on the surface of upconversion nanoparticle@magnetic nanoparticle through polymerization. The structure and recognition characterizations of multifunctional fluorescent sensing materials were evaluated. Under optimal condition, the imprinting factor of sensing materials was 3.63, and the fluorescence intensity of sensing materials decreased linearly with increasing concentration of deltamethrin from 0.001 to 1 mg L-1 with a detection limit of 0.749 µg L-1, and a relative standard deviation of 3.10% was obtained with 5 mg L-1 deltamethrin. The sensing materials showed a high selectivity and were successfully utilized for the detection of deltamethrin in grapes and cabbages; the results showed that the recoveries for two samples obtained were 95.6-102% and 91.8-105%.

Determination of organophosphorus and synthetic pyrethroid pesticide residues and their variability in large size fruit crops.

BACKGROUND: Variability of pesticide residues in food item plays a key role for the evaluation of consumer food safety. However, variability factors (VFs) derived from the large size fruit crops are still scarce. Therefore, the present work was aimed to quantify pesticide residues and to estimate VFs in large size fruit crops of mango and guava. RESULTS: A total of 140 mango and 130 guava samples from different marketplaces in Bangladesh were collected to estimate the variability of pesticide residues (acephate, diazinon, malathion, fenitrothion, chlorpyrifos, quinalphos, dimethoate and cypermethrin) by in-house validated methods based on modified QuEChERS extraction and gas chromatography coupled with electron capture detector (ECD) and flame thermionic detector (FTD). The method was validated at three fortification levels (0.01, 0.10 and 0.30 mg kg-1 ) and satisfactory recoveries (80-111%) with relative standard deviation (RSDr ) ≤ 13% were achieved. A wide variation of residues was found in the analyzed samples. In the case of mango, the ranges of residues were 0.011-0.314, 0.015-0.04, and 0.05-0.291 mg kg-1 , respectively, for cypermethrin, chlorpyrifos, and dimethoate, while in the case of guava, the ranges were 0.04-0.113, and 0.03-0.290 mg kg-1 , respectively, for cypermethrin and acephate. The average VF for mango was 4.06 and it was 5.70 for guava. CONCLUSION: VFs originating from the marketed samples of mango and guava are reported in this study for the first time. The estimated VFs were higher than the default value of 3, therefore, the default VFs should be reconsidered when more data are obtained regarding large size crops. © 2021 Society of Chemical Industry.