A national-scale cumulative exposure assessment of organophosphorus pesticides through dietary vegetable consumption in China

Results from the Danish monitoring programme on pesticide residues from the period 2012-2017 - frequencies and trends in detected pesticides

In order to assess compliance with maximum residue levels in foods and evaluate the exposure of the Danish population to pesticides, a comprehensive monitoring programme was conducted. The work from 2012-2017 involved testing pesticide residues in fruits, vegetables, cereals, animal product and processed commodities. The sampling strategy, mainly based on exposure calculations and previous findings, involved the collection of 13,492 samples primarily from fresh conventional and organic produces on the Danish market. The origin of the samples varied, with 34% being of Danish origin and 67% originating from EU and non-EU countries. The results revealed that residues in conventionally grown produce were detected in 54% of the fruit and vegetable samples, and 30% of the cereal samples. Additionally, residues above the maximum residue limits were found in 1.8% of these samples, most frequently in fruits. As previous years, more residues were found in samples of foreign origin compared to samples of Danish origin. Compared to earlier findings more than 40 pesticides were detected for the first time and including boscalid, imidacloprid, thiacloprid, etofenprox, and spinosad, all detected more than 100 times. The data shows that detection of PFAS pesticides has increased dramatically, from 24 in 2006 to 412 in 2022.

Advances on multiclass pesticide residue determination in citrus fruits and citrus-derived products - A critical review

The application of agrochemicals in citrus fruits is widely used to improve the quality of crops, increase production yields, and prolong post-harvest life. However, these substances are potentially toxic for humans and the ecosystem due to their widespread use, high stability, and bioaccumulation. Conventional techniques for determining pesticide residues in citrus fruits are chromatographic methods coupled with different detectors. However, in recent years, the need for analytical strategies that are less polluting for the environment has encouraged the appearance of new alternatives, such as sensors and biosensors, which allow selective and sensitive detection of pesticide residues in real time. A comprehensive overview of the analytical platforms used to determine pesticide residues in citrus fruits and citrus-derived products is presented herein. The review focuses on the evolution of these methods since 2015, their limitations, and possible future perspectives for improving pesticide residue determination and reducing environmental contamination.

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.

Characterizing the cumulative health risks of 19 kinds of pesticides in Chinese food from the cancer and non-cancer perspective

Food safety is an important issue of most concern for health, while pesticides are one of the main threats to food safety. In view of the potential health hazard of pesticides in food, the cancer and non-cancer risks were assessed for 19 kinds of pesticides in Chinese food in this study. Furthermore, the health risks of different types of pesticides were compared to uncover the most polluted pesticide types in this study. Results show that methyl parathion, dichlorvos and 2,4-D residues in some food groups exceed the Chinese food standards. The cumulative disease burden of six carcinogenic pesticides for people older than 40 years ranges from 1.03 × 10-6 to 2.27 × 10-6, which exceeds the WHO recommended limit of 10-6. The non-cancer risks of 13 kinds of pesticides are all lower than 1 and will not pose appreciable health risk to the consumers. Livestock and poultry (contribution rate = 38.93%) and Milk and dairy products (contribution rate = 22.38%) are the dominate risk exposure sources for carcinogenic pesticides while staple foods (contribution rate = 31.62%) and vegetables (contribution rate = 21.5%) are the main risk exposure sources for non-carcinogenic pesticides. Comparing the risks of different pesticide types, insecticide is the most harmful category in this study, followed by herbicide and acaricide. This study characterized the health risks of pesticides in Chinese food and provided a scientific basis for pesticide management.

Dietary exposure risk assessment of pyrethroids in fruits and vegetables: a national scale investigation

The pyrethroids (PYRs) were extensively used to increase agriculture outputs. However, the cumulative exposures of PYRs would bring about potential risks through food intake. It is an urgent requirement to explore the cumulative exposures on the fruits and vegetables. In this study, a total of 1720 samples incorporating eight primary fruits and vegetables collected around China were investigated to assess the health risk for adults and children from eight PYRs. The relative potency factor (RPF) method was employed to reveal both chronic and acute cumulative exposure. As a result, the hazard index (HI) were 0.004 ~ 0.200% and 11.85 ~ 99.19% for chronic and acute cumulative dietary exposure, respectively. The national wide investigation indicated the cumulative assessments were not hazardous. Besides, the acute intake of pear, grape, and lettuce should be paid on more attention, particularly. This study provides compelling evidence to develop relative policy and regulation to improve the food quality and safety.

The integrated exposure assessment and potential risks of five organophosphorus pesticides in vegetables in Zhejiang, China (2018-2020)

This research surveyed the concentrations of five organophosphorus pesticides (OPs) in vegetables with the purpose of assessing the potential integrated health risks of residents. From 2018 to 2020, 870 samples of eight kinds of vegetables from Zhejiang Province were collected. Gas chromatography coupled with a flame photometric detector (GC-FPD) analyzed the five OPs. OPs were most frequently detected in celery (18.9% of samples), cowpeas (18.3% of samples), and leeks (16.9% of samples) compared to other vegetables. Among the 11 cities in Zhejiang, the cities with high detection rates of OPs were Ningbo and Hangzhou. The integrated concentrations of OPs in different cities ranged from 71.9 to 376 μg/kg. The cumulative risk assessment revealed that the estimated daily intake (EDI) of leek in Wenzhou was the highest, which was 0.0077 (mg/kg bw) and 0.0059 (mg/kg bw) in adults and children respectively. The health risks of residents who consume these vegetables were within a safe range. The data provided demonstrate the distribution and potential health hazards of OPs in commonly consumed vegetables.

Contamination, ecological, and health risk assessment of heavy metals and organophosphorus pesticides in single, double, and ratoon cropping of rice: a case study in Mazandaran, North of Iran

This study investigated the contamination and health risk assessment of heavy metals and organophosphorus pesticides in single, double, and ratoon cropping of rice in Mazandaran province, north of Iran. A total of 17 sampling locations in rice farms were selected and soil and rice samples were collected from farms in 5 counties of Mazandaran. Soil and rice samples were then transferred to the lab for further analysis. The concentration of pesticides and heavy metals was then analyzed using gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Mercury was analyzed using a Leco mercury analyzer. Target hazard quotient (THQ), total target hazard quotient (TTHQ), carcinogenic risk (CR), and total carcinogenic risk (TCR) in children and adults were used. Potential ecological risk also was used to test the possible hazards of heavy metals to the environment. Heavy metals concentration in rice and soil samples in different farming steps revealed different levels. THQ showed no considerable risk in consuming contaminated rice to adults and children considered, while TTHQ revealed potential non-carcinogenic risks. Ni had the most carcinogenic risks to target human groups, and TCR showed carcinogenicity for carcinogenic heavy metals in all stations. Findings showed no ecological risks of metals to the environment. In conclusion, rice farmers in Mazandaran use the lands multiple times during the year to increase the performance, function, quality, and quantity of rice, but the possible toxic effects of heavy metals and pesticides on consumers and the environment should not be overlooked.

Hematological indices as indicators of inflammation induced by exposure to pesticides

Pesticide toxicity, both acute and chronic, is a global public health concern. Pesticides are involved in abnormal inflammatory responses by interfering with the normal physiology and metabolic status of cells. In this regard, inflammatory indices aggregate index of systemic inflammation (AISI), monocyte-to-high-density lipoprotein ratio, monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte platelet ratio (NLPR), neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune inflammation index, and systemic inflammation response index (SIRI) have been used as predictive markers of inflammatory status in several diseases and also in acute poisoning events. This study aimed to determine systemic inflammation indices and their relationship with pesticide exposure from urban sprayers in 302 individuals categorized into three groups (reference group and moderate and high exposure groups). The data suggest that the AISI, MLR, NLPR, and SIRI indices were significantly higher in the exposed groups compared with the reference group. In conclusion, this study proposes that inflammation indices warrant further attention in order to assess their value as early biomarkers of acute and chronic pesticide intoxication.

Rapid Detection of Malathion, Phoxim and Thiram on Orange Surfaces Using Ag Nanoparticle Modified PDMS as Surface-Enhanced Raman Spectroscopy Substrate

Malathion, phoxim, and thiram are organophosphates and organosulfur pesticides widely used in agricultural products. The residues of these pesticides present a direct threat to human health. Rapid and on-site detection is critical for minimizing such risks. In this work, a simple approach was introduced using a flexible surface-enhanced Raman spectroscopy (SERS) substrate. The prepared Ag nanoparticles-polydimethylsiloxane (AgNPs-PDMS) substrate showed high SERS activity, good precision (relative standard deviation = 5.33%), and stability (30 days) after optimization. For target pesticides, the linear relationship between characteristic SERS bands and concentrations were achieved in the range of 10~1000, 100~5000, and 50~5000 μg L^-1 with LODs down to 3.62, 41.46, and 15.69 μg L^-1 for thiram, malathion, and phoxim, respectively. Moreover, SERS spectra of mixed samples indicated that three pesticides can be identified simultaneously, with recovery rates between 96.5 ± 3.3% and 118.9 ± 2.4%, thus providing an ideal platform for detecting more than one target. Pesticide residues on orange surfaces can be simply determined through swabbing with the flexible substrate before acquiring the SERS signal. This study demonstrated that the prepared substrate can be used for the rapid detection of pesticides on real samples. Overall, this method greatly simplified the pre-treatment procedure, thus serving as a promising analytical tool for rapid and nondestructive screening of malathion, phoxim, and thiram on various agricultural products.

Cumulative Risk Assessment of Dietary Exposure to Pesticide Residues in Brown Rice (Oryza sativa L.) from the Three Main Rice-Growing Regions in China during 2016–2020

The residual levels of 25 monitored pesticides in 6,229 brown rice samples obtained from the 17 provinces of the three main rice-growing regions in China during 2016–2020 were analyzed, and the cumulative risks of chronic and acute exposure to pesticides for the Chinese population were assessed. The QuEChERS extraction coupled with liquid chromatography-mass spectrometry for simultaneous determination of 25 pesticide residues in brown rice was developed and validated with good accuracy and precision (recoveries of 70%–120% and RSD ≤20%). The overall detection rate and over the maximum residue limit (MRL) rate of pesticides in brown rice decreased from 39.15% and 3.59% in 2016 to 34.11% and 1.53% in 2020, respectively. The Yangtze River basin had a higher detection rate and over MRL rate (43.14% and 2.88%, respectively) compared with the Southeast Coastal region (37.28% and 2.77%) and the Northeast Plain (11.28% and 0.17%). Isoprothiolane (13.57%) and carbendazim (8.32%) were the most frequently detected in rice samples. Pesticide residues exceeding the MRLs were found most often in triazophos (0.75%) and isocarbophos (0.51%). The risk ranking of pesticide residues based on the ranking matrix showed that carbofuran, methamidophos, and isocarbophos had the highest residual risk scores of 25.09, 25.01, and 25.00, respectively. 17.7% of rice samples contained two or more pesticide residues. The cumulative risk assessments based on the relative potency factor (RPF) approach revealed that the cumulative risks of chronic and acute dietary exposure to organophosphorus, neonicotinoid insecticides, and triazole fungicides from rice ranged from 7.43 × 10−4 to 3.36 × 10−2, which were not considered of health concern. The study provides national-scale information on the contamination levels and health risks of pesticide residues in rice, which can help develop continuous monitoring programs for pesticide residue contamination in rice in China.

Dissipation and Residue of Metalaxyl-M and Azoxystrobin in Scallions and Cumulative Risk Assessment of Dietary Exposure to Hepatotoxicity

Metalaxyl-M and azoxystrobin have been used to control various fungal diseases on scallion and other crops. In view of the adverse toxic effects of both on the mammalian liver, it is necessary to conduct a cumulative risk assessment of their dietary exposure to consumers. The residues of metalaxyl-M and azoxystrobin on scallion were determined by a quick, easy, cheap, effective, rugged, and safe method (QuEChERS) combined with high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). The half-lives were about 1.15 and 3.89 days, respectively, and the final residues after a seven-day harvest interval were <0.001−0.088 mg/kg and 0.190−4.687 mg/kg, respectively. The cumulative dietary risk quotient of the two fungicides to Chinese consumers calculated by the probability model is 13.94%~41.25%. According to the results of the contribution analysis, the risk posed by azoxystrobin is much greater than that of metalaxyl-M. Although metalaxyl-M and azoxystrobin do not pose a cumulative risk to Chinese consumers, the risk to children and adolescents is significantly higher than that to adults. This suggests that in future research, more consideration should be given to the cumulative risk of compounds to vulnerable groups.

Operating pesticide use reduction within the boundary of food security in peri-urban settings

Pesticide use in peri-urban areas affects the urban environment and public health, and reducing the use may present food security issues for urban dwellers. In this study, we explore how a municipality-adopted goal of a 20% reduction in pesticide use could be achieved, along with local food security and environmental implications, for Shanghai located in the densely populated East China. A regional Shanghai Agricultural Sector Model incorporating district- and technology-varying crop budgets, was developed to simulate the effects of pesticide reduction policy. Here we find that achieving the reduction goal had the largest implications in districts with high pesticide use totals and intensities, potentially reducing pesticide non-point source pollution in the Yangtze River Estuary and Dianshan Lake; the production levels of rice and leafy vegetables would be most affected; and adopting machinery that allows more precise pesticide application modulates these results. Moreover, imposing the requirements at the district-level caused more severe local food security concerns, and less environmental benefits. Furthermore, a closed Shanghai's agricultural economy would substantially enlarge the regional heterogeneity in the above-mentioned outcomes. Exploring the effects of a quantity control policy on current-use pesticides at different aggregation levels has important implications for regulating the use of agrochemicals.

Evaluation of chiral triticonazole in three kinds of fruits: enantioseparation, degradation, and dietary risk assessment

The enantioselective behaviors of chiral pesticides would affect the accuracy of risk assessment. This study evaluated the enantioselectivity of chiral triticonazole (a widely used fungicide) in three kinds of fruits. Firstly, the enantioseparation of triticonazole enantiomers was carried out within 1.2 min utilizing CHIRALPAK OJ-3 column with a mixture of CO₂ and methanol (93:7, v/v) using SFC-MS/MS. Secondly, field trials were conducted to clarify the enantioselective degradation and residue of S-( +)-triticonazole and R-(-)-triticonazole in fruits. The initial concentrations of rac-triticonazole were 25.1-93.1 ng/g, and enantioselective degradation was observed in pear, peach, and jujube after 2 h, 10 days, and 3 days, respectively. The degradation of S-( +)-triticonazole was fastest in pear (T_1/2, 2.01 days), while the T_1/2 of R-(-)-triticonazole was 5.02 days. The residue concentrations of rac-triticonazole were less than the MRL set by EU (10 ng/g) on the 3rd and 21st day in pear and peach, respectively, which were lower than 10 ng/g in jujube on the 30th day (no MRL). Finally, we found that the dietary intake risks of rac-triticonazole in fruits were low for 2-7 age, 20-50 age/female, and 20-50 age/male. The current study could provide complimentary references for the rational usage, MRL formulation, and risk assessment of chiral triticonazole.

Cumulative risk assessment of dietary exposure to triazole fungicides from 13 daily-consumed foods in China

The agroeconomic benefits of the routine use of triazole fungicides on crops have been evident for more than 40 years. However, increasing evidence shows that residues of triazoles are ubiquitous in various foods and thus could pose a potential health risk to humans. We analyzed 3406 samples of 13 food commodities that were collected from markets in 9 regions across China, and assessed the health risk of both chronic and acute exposure to the triazoles for Chinese children (1-6 years old) and the general population. Among all samples, 55.52% had triazoles in concentrations of 0.10-803.30 μg/kg, and 29.77% of samples contained a combination of 2-7 triazoles. Tebuconazole and difenoconazole were the most commonly found triazoles in the foods, being detected in 33.44% and 30.45% of samples, respectively. Chronic and acute cumulative risk assessment for total triazoles based on a relative potency factor method revealed that exposure to triazoles from these particular commodities was below the levels that might pose a health risk (chronic hazard index range, 5.90×10^-7 to 1.83×10^-3; acute hazard index range, 7.77×10^-5 to 0.39, below 1). Notably, dietary exposure risk for children was greater than that for the general population-particularly for the acute intake of mandarin, grape, and cucumber (acute hazard index values of 0.35-0.39). Despite the low health risk, the potential hazards of exposure to triazoles should raise public concern owing to their ubiquitous presence in common foods and potential cumulative effects.

Risk assessment approaches for evaluating cumulative exposures to multiple pesticide residues in agro-products using seasonal vegetable monitoring data from Hainan, China: a case study

Risks from combined exposure to multiple chemicals in food have prompted a growing concern for their effect on human health. Risk management of chemical mixtures should be based on developing and harmonizing methodologies to scientifically evaluate their cumulative adverse effects. In this study, a simplified tiered approach of cumulative exposure assessment is described along with a case study of vegetables in China's Hainan province during 2012-2014. This case study could be a reference for the Chinese National Risk Assessment Programs for vegetable and fruit products. In the proposed assessment approach, Tier 1 acts as a screening tier to categorize and evaluate chemicals under a conservative scenario, and it prioritizes the pesticides of most concern. Tier 2 refines the grouping of substances from Tier 1 and normalizes the toxic potency of the chemicals to sum the exposure of chemical mixtures in a given assessment group. Tier 3 applies the refined exposure model and the input parameter distribution to create probabilistic models using Monte Carlo simulation. This approach will be helpful in the cumulative exposure assessment where data on pesticide residues are sufficient, but the individual dietary consumption is inadequate.

Occurrence of pesticides in white tea and a corresponding risk exposure assessment for the different residents in Fujian, China

White tea has been of increasing public interest worldwide owing to its health benefits. Based on 2 years of surveillance, the long-term and cumulative chronic exposure risks of pesticide residues through white tea drinking were assessed for different subpopulations in Fujian, China. Twenty-five different pesticides were found, and 74.8% of samples contained at least one pesticide residue. The most frequently detected pesticide was bifenthrin with detection rates of 61.6%. Risk assessment was performed using both the deterministic approach and semiprobabilistic model under the best-case and the worst-case scenarios. The results demonstrated that the dietary risks were extremely low for six different subpopulations in which the risks for adults over the age of 41 were relatively higher. The risk ranking scheme indicated that isocarbophos and triazophos were considered to be of medium risk. The different use suggestions for the 25 positive pesticides are proposed to further minimize the exposure risk to consumer health. PRACTICAL APPLICATION: Tea is the second most popular nonalcoholic beverage throughout the world. Pesticides are used to improve the yield of tea. Pesticide residues in tea could be one of the exposure pathways for consumers. Monitoring residual levels and assessing the health risk assessment in tea are thus in an urge.

Pesticides and risk assessment in Shanghai fruit and raw eaten vegetables

A database of 392 pesticides established by an Ultrahigh performance liquid chromatography-tandem Q/Orbitrap high-resolution mass spectrometer (UPLC-Q/Orbitrap-HRMS) was used to screen multiple residues of pesticides in fruit and raw eaten vegetables from planting farms in Shanghai. Risk assessment was conducted with the screened results of the determined pesticides as to evaluate food safety. In 95% of the samples, one or more pesticides had a content below the maximum residue limits (MRLs) as set in the national Chinese standard. The co-occurrence of multi-residues of pesticides was more severe in peach and muskmelon, when compared with other food. All hazard index values of different groups were in the range of 0.19% to 12.3%, demonstrating that chronic dietary risk of studied fruits and raw eaten vegetables is low and the studied food samples were safe for human consumption in terms of these detected pesticides.

Residual characteristics and potential integrated risk assessment of synthetic pyrethroids in leafy vegetables from Zhejiang in China - Based on a 3-year investigation

Leafy vegetables have high nutritional value and are very popular in China. However, the long-term variation in residues and integrated risks of synthetic pyrethroids (SPs) in these vegetables have not been well examined. In this study, a total of 1005 samples were collected from 55 markets during 2017-2019. The cumulative exposure to nine kinds of SPs in Zhejiang, China, through the consumption of nine leafy vegetables was analyzed, and the potential integrated risk was assessed by the relative potency factor. A total of 191 samples were detected with SPs residues. The most frequently detected SPs were λ-cyhalothrin and cypermethrin. The integrated risk assessment results revealed that the dietary risk for these SPs via leafy vegetable exposure is acceptable for children, adults and elderly individuals. The data provided here will be helpful for the government to formulate food policies in China.

Risk assessment of heavy metals in milk from cows reared around industrial areas in India

This study assessed the health risk associated with exposure to heavy metals through consumption of milk from cows reared around industrial areas in India. Heavy metals, namely Cu, Zn, Cr, Pb, and Cd, were determined in water and forage from four locations as well as in milk produced by dairy cattle raised in these locations, using inductively coupled plasma-mass spectrometry. A quantitative risk assessment using probabilistic approaches was performed to assess the exposure of adults and children to the heavy metals via milk consumption. In milk samples, the highest levels of Cd and Pb were 0.18 mg L^-1 and 0.37 mg L^-1, respectively, which were above the international permissible levels. Possible sources of Pb in the milk could be the industrial by-products and wastes or automobiles exhaust gas. Significant (P < 0.05) positive relationships were found between the concentration of Cu, Cr, Pb, and Cd in milk and in the environmental samples (water or forage). Exposure assessment showed that milk consumers were mostly exposed to Zn, Cd, and Pb, with 63.7%, 51.2%, and 41.2% of children exposed to a dose greater than the references dose for these metals, respectively. Our results suggest that industrial activities lead to possible transfer of heavy metals to cows from their rearing environment (water, plant), which can be accumulated and cause potential health risks to milk consumers. The outcome of this study can be used by policy makers to manage the potential health risk.

Broad-spectrum electrochemical immunosensor based on one-step electrodeposition of AuNP-Abs and Prussian blue nanocomposite for organophosphorus pesticide detection

Broad-spectrum antibodies can effectively recognize substances with similar structures and have broad application prospects in field rapid detection. In this study, broad-spectrum antibodies (Abs) against organophosphorus pesticides (OPs) were used as sensitive recognition elements, which could effectively recognize most OPs. Gold nanoparticles (AuNPs) have good biocompatibility. It combined with Abs to form a gold-labeled probe (AuNPs-Abs), which enhances the effective binding of antibodies to nanomaterials. Prussian blue (PB) was added to electrodeposition solution to enhance the conductivity, resulting in superior electrochemical performance. The AuNP-Abs-PB composite film was prepared by electrodeposition on the electrode surface to improve the anti-interference ability and stability of the immunosensor. Under the optimal experimental conditions, the immunosensor had a wide detection range (IC₂₀-IC₈₀: 1.82 × 10^-3-3.29 × 10⁴ ng/mL) and high sensitivity. Most importantly, it was simple to be prepared and could be used to detect multiple OPs.

Trace analysis of organophosphorus pesticide residues in fruit juices and vegetables by an electrochemically fabricated solid-phase microextraction fiber coated with a layer-by-layer graphenized graphite/graphene oxide/polyaniline nanocomposite

Herein, a solid-phase microextraction pencil lead fiber coated with a layer-by-layer graphenized graphite/graphene oxide/polyaniline nanocomposite (GG/GO/PANI) was fabricated by an in situ electrochemical technique for the trace analysis of organophosphorus pesticide residues in packed grape and apple juice and also fresh tomato samples. The effects of various parameters, including the type of desorption solvent, adsorption time, desorption time, pH, salt addition, and stirring rate, on the extraction efficiency of the studied pesticides were investigated and accordingly, these parameters were optimized. The proposed fiber demonstrated desirable linear ranges (0.01-300 μg L-1) with good correlation coefficients (R2 ≥ 0.996) as well as low limits of detection (0.003-0.03 μg L-1) for the studied pesticides. The relative standard deviations (n = 5) for the extraction of 50 μg L-1 of each analyte were less than 7 and 11.5% for inter and intra-day precisions, respectively. This fast, facile, and repeatable electrochemical fabrication method produced a porous and homogeneous coating. The proposed fiber demonstrated good extraction efficiency, high stability, and long life-time despite being low cost. The successful application of the proposed fiber for the trace determination of pesticides in complex food matrices was proven by the satisfactory relative recoveries of 80.7-116.5%.

Enhanced Solubility, Stability, and Herbicidal Activity of the Herbicide Diuron by Complex Formation with β-Cyclodextrin

The herbicide diuron is hardly soluble in water and most organic solvents and is usually made into a wettable powder or mixed with soil when used, which causes environmental risk and a reduction in herbicidal efficacy. In this study, the physicochemical properties were changed by using β-cyclodextrin (β-CD) to encapsulate diuron to form an inclusion complex. Some key technologies, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and nuclear magnetic resonance (1H NMR), were used to characterize the inclusion complex. The stoichiometry of the inclusion complex was determined by recording the 1H NMR spectrum or by using a diagram of inclusion ratios. A phase solubility study proved that the formed inclusion complex exhibited higher water solubility. Thermogravimetric analysis (TGA) demonstrated that the formed inclusion complex exhibited better thermal stability. Biological activity studies indicated that the herbicidal activity, in terms of herbicide removal, of the formed inclusion complex was higher than that of the original diuron. In general, the formation of the inclusion complex could reduce the environmental damage caused by diuron and enhance its herbicidal activity, providing an environmentally friendly method for using diuron.