Application of the QuEChERS procedure and LC–MS/MS for the assessment of neonicotinoid insecticide residues in cocoa beans and shells

Source and health risk of urinary neonicotinoids in Tibetan pregnant women

High altitude could influence the level of exposure to neonicotinoids, but relevant data remain limited for people living in Tibet. We investigated 476 Tibetan pregnant women from Lhasa of Tibet, China in 2021 and measured eight neonicotinoids and four metabolites in urine. Food consumption was investigated by a food frequency questionnaire. Health risk was assessed by using hazard quotient (HQ) and hazard index (HI) based on acceptable daily dose or chronic reference dose. Neonicotinoids and metabolites were overall detected in 56.5% of urine samples with a median concentration being 0.73 μg g-1 creatinine. Four neonicotinoids or metabolites were detected in more than 10% of urine samples, including N-desmethyl-acetamiprid (47.5%), clothianidin (15.5%), thiamethoxam (16.0%), and imidacloprid (10.5%). Annual household income, family smoking, and pre-pregnancy body mass index were associated with the detection frequencies of neonicotinoids. Pregnant women with a higher consumption frequency of wheat, rice, fresh vegetable, fresh fruit, beef and mutton, fresh milk, yoghourt, candy and chocolate, or carbonated drinks had a higher detection frequency of neonicotinoids. Both HQ and HI were less than one. There was an evident exposure to neonicotinoids in Tibetan pregnant women with both plant- and animal-derived food items as exposure sources, but a low health risk was found based on current safety thresholds.

Influence of tobacco product wastes in a protected coastal reserve adjacent to urbanization

The present study, conducted at the Kendall-Frost Mission Bay Marsh Reserve in San Diego, California, aimed to assess tobacco-related pollutants in urban waters, a topic with limited prior research. Across 26 events occurring between November 2019 and February 2022, encompassing both wet and dry seasons at two outfall sites (Noyes St. and Olney St.), water and sediment samples were subjected to analysis for nicotine and cotinine levels, with Noyes St. displaying wide variation in nicotine concentrations, reaching a peak of 50.75 ng/L in water samples, whereas Olney St. recorded a peak of 1.46 ng/L. Wet seasons consistently had higher nicotine levels in water, suggesting the possibility of tobacco litter entering the reserve through stormwater runoff. Cotinine was detected in both sites in both water and sediment samples; however, these levels were considerably lower in comparison to nicotine concentrations. Limited research assesses aquatic environmental pollution from tobacco use and disposal, especially in protected areas like urban natural reserves. This study was conducted at the Kendall-Frost Mission Bay Marsh Reserve in San Diego, California, to evaluate tobacco-related pollutants in San Diego's urban waters. Twenty-six sampling events between November 2019 and February 2022, spanning wet and dry seasons at two outfall sites, were conducted. Nicotine and cotinine, a major ingredient of tobacco and its metabolite, were analyzed in the collected water and sediment samples. Nicotine concentrations differed substantially between the outfall locations (Noyes St. and Olney St.), with Noyes St. displaying wide variations, averaging at 9.31 (±13.24) ng/L with a maximum concentration of 50.75 ng/L, and Olney St. at 0.53 (±0.41) ng/L with a maximum concentration of 1.46 ng/L in water samples. In both locations, the nicotine concentrations in water samples were higher during wet seasons than dry seasons, and this pattern was more significant at Noyes St. outfall than at Olney St. outfall, which received not only stormwater runoff but also was connected to Mission Bay. Although this pattern did not directly align with sediment nicotine levels at both sites, maximum nicotine concentration in Noyes St. sediments during wet seasons was approximately 120 times higher than in Olney St. sediments. Regarding cotinine, Noyes St. outfall water averaged 3.17 ng/L (±1.88), and Olney St. water averaged 1.09 ng/L (±1.06). Similar to nicotine, the cotinine concentrations were higher in Noyes St. water and sediment compared to Olney St., but overall, the cotinine concentrations in both water and sediment were much lower than the corresponding nicotine concentrations. The study identifies urban stormwater runoff as a potential source of nicotine and cotinine pollution in a protected reserve, implicating tobacco product litter and human tobacco use as contributing factors.

An LC-MS/MS Method for the Simultaneous Analysis of 380 Pesticides in Soybeans, Kidney Beans, Black Soybeans, and Mung Beans: The Effect of Bean Grinding on Incurred Residues and Partitioning

The significance of sample grinding is frequently disregarded during the development of analytical methods, which are often validated with spiked samples that may not accurately reflect incurred residues. This study investigated the particle size of ground beans as a key factor in optimizing extraction efficiency in order to develop a simple quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based modified method for identifying 380 pesticides in beans using liquid chromatography-tandem mass spectrometry. The efficacy of pesticide extraction was found to be significantly affected by particle size. With small particle sizes (>40 mesh), no supernatant was recovered after QuEChERS partitioning. Therefore, a simple modification was performed before partitioning. The modified method was validated for selective extraction of pesticides, limits of quantification, linearity, accuracy, and precision. This method is simple to implement and, therefore, useful for the analysis of pesticide residues in beans.

Screening for pesticide residues in cocoa (Theobroma cacao L.) by portable infrared spectroscopy

Rapid assessment of pesticide residues ensures cocoa bean quality and marketability. In this study, a portable FTIR instrument equipped with a triple reflection attenuated total reflectance (ATR) accessory was used to screen cocoa beans for pesticide residues. Cocoa beans (n = 75) were obtained from major cocoa growing regions of Peru and were quantified for pesticides by gas chromatography (GC) or liquid chromatography (LC) coupled with mass spectrometry (MS). The FTIR spectra were used to detect the presence of pesticides in cocoa beans or lipid fraction (butter) by using a pattern recognition (Soft Independent Modeling by Class Analogy, SIMCA) algorithm, which produced a significant discrimination for cocoa nibs (free or with pesticides). The variables related to the class grouping were assigned to the aliphatic (3200-2800 cm^-1) region with an interclass distance (ICD) of 3.3. Subsequently, the concentration of pesticides in cocoa beans was predicted using a partial least squares regression analysis (PLSR), using an internal validation of the PLRS model, the cross-validation correlation coefficient (R_val = 0.954) and the cross-validation standard error (SECV = 14.9 mg/kg) were obtained. Additionally, an external validation was performed, obtaining the prediction correlation coefficient (R_pre = 0.940) and the standard error of prediction (SEP = 16.0 μg/kg) with high statistical performances, which demonstrates the excellent predictability of the PLSR model in a similar real application. The developed FTIR method presented limits of detection and quantification (LOD = 9.8 μg/kg; LOQ = 23.1 μg/kg) with four optimum factors (PC). Mid-infrared spectroscopy (MIR) offered a viable alternative for field screening of cocoa.

Knowledge, perception, and pesticide application practices among smallholder cocoa farmers in four Ghanaian cocoa-growing regions

Pesticides are widely used in Ghana, especially in cocoa farming. However, the practice is suboptimal and unsupervised. Incorrect use of these chemicals can seriously harm human health, the environment, and economies that rely on these farmers' output. The study assessed cocoa farmers' pesticide knowledge, practices, and risk perception. Four hundred and four cocoa farmers were chosen randomly from 26 communities in four cocoa-growing regions of Ghana to answer questions about their risk knowledge, awareness, and practices, including personal protective equipment, storage and disposal of leftover pesticides, and used containers. The study revealed that 87% of the respondents belonged to cooperatives and certification groups. There was a significant positive relationship between group membership and benefits derived from inputs and training in pesticide use. About 70% of insecticides used were approved by the Ghana Cocoa Board, with neonicotinoids and pyrethroids being the most highly used insecticide classes in cocoa farms. Although farmers claimed adequate pesticide knowledge, this did not translate into practice, with the majority exhibiting improper pesticide storage, application, and disposal practices. Farmers appeared to know a lot but lacked the skills and attitude to put their knowledge to use. The improper practices appear to manifest in a variety of health symptoms experienced by farmers as a result of chemical exposure. The findings from this study suggest that cocoa farmers in Ghana require adequate practical training and support on pesticide use to reduce their associated health risks, protect the environment and ensure sustainable cocoa production in the world's second-largest cocoa bean exporter.

A comprehensive review on the pretreatment and detection methods of neonicotinoid insecticides in food and environmental samples

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The metabolism and residue status of neonicotinoids were briefly summarized in this work.

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Sample pretreatment techniques for the analysis of neonicotinoids were critically discussed.

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The commonly used detection methods for neonicotinoids residues were also pointed out.

In recent years, the residues of neonicotinoid insecticide in food and environmental samples have attracted extensive attention. Neonicotinoids have many adverse effects on human health, such as cancer, chronic disease, birth defects, and infertility. They have substantial toxicity to some non-target organisms (especially bees). Hence, monitoring the residues of neonicotinoid insecticides in foodstuffs is necessary to guarantee public health and ecological stability. This review aims to summarize and assess the metabolic features, residue status, sample pretreatment methods (solid-phase extraction (SPE), Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS), and some novel pretreatment methods), and detection methods (instrument detection, immunoassay, and some innovative detection methods) for neonicotinoid insecticide residues in food and environmental samples. This review provides detailed references and discussion for the analysis of neonicotinoid insecticide residues, which can effectively promote the establishment of innovative detection methods for neonicotinoid insecticide residues.

QuEChERS Method Combined with Gas- and Liquid-Chromatography High Resolution Mass Spectrometry to Screen and Confirm 237 Pesticides and Metabolites in Cottonseed Hull

Cottonseed hull is a livestock feed with large daily consumption. If pesticide residues exceed the standard, it is easy for them to be introduced into the human body through the food chain, with potential harm to consumer health. A method for multi-residue analysis of 237 pesticides and their metabolites in cottonseed hull was developed by gas-chromatography and liquid-chromatography time-of-flight mass spectrometry (GC-QTOF/MS and LC-QTOF/MS). After being hydrated, a sample was extracted with 1% acetic acid in acetonitrile, then purified in a clean-up tube containing 400 mg MgSO4, 100 mg PSA, and 100 mg C18. The results showed that this method has a significant effect in removing co-extracts from the oily matrix. The screening detection limit (SDL) was in the range of 0.2–20 μg/kg, and the limit of quantification (LOQ) was in the range of 0.2–20 μg/kg. The recovery was verified at the spiked levels of 1-, 2-, and 10-times LOQ (n = 6), and the 237 pesticides were successfully verified. The percentages of pesticides with recovery in the range of 70–120% were 91.6%, 92.8%, and 94.5%, respectively, and the relative standard deviations (RSDs) of all pesticides were less than 20%. This method was successfully applied to the detection of real samples. Finally, this study effectively reduced the matrix effect of cottonseed hull, which provided necessary data support for the analysis of pesticide residues in oil crops.

Development of an isotope dilution liquid chromatography/tandem mass spectrometry method for the accurate determination of neonicotinoid pesticides, imidacloprid, clothianidin, and thiamethoxam in kimchi cabbage reference materials

A method based on isotope dilution liquid chromatography/tandem mass spectrometry (ID-LC/MS/MS) was established as a candidate reference method for accurate determination of neonicotinoid pesticides, imidacloprid, clothianidin, and thiamethoxam in kimchi cabbage. Their deuterated isotopes, imidacloprid-d4, chlothianidin-d3, and thiamethoxam-d4 were used as internal standards. The combination of HLB and Carb solid-phase extraction (SPE) cartridges was used to clean-up kimchi cabbage extracts. The ID-LC/MS/MS conditions were optimized with fortified kimchi cabbage samples for validation. Imidacloprid in the ERM-BC403 cucumber sample (0.627 ± 0.026) mg/kg was analyzed with the developed method, and the measured value (0.604 ± 0.028) mg/kg agreed within their uncertainties. The developed method was employed for the certification of kimchi cabbage reference materials prepared in this laboratory. The measured values of imidacloprid, clothianidin, and thiamethoxam are (0.860 ± 0.020) mg/kg, (0.524 ± 0.012) mg/kg, (0.787 ± 0.014) mg/kg, respectively. The standard deviation of the measured values for ten bottles was < 1%, and the measured values after one year agreed with their first measurements indicating reliable repeatability and reproducibility of the developed method.

Development and validation of a micro-QuEChERS method with high-throughput enhanced matrix removal followed with UHPLC-QqQ-MS/MS for analysis of raspberry ketone-related phenolic compounds in adipose tissues

Raspberry ketone (RK) is a major flavor compound in red raspberries, and it has been marketed as a popular weight-loss dietary supplement with high potential in accumulating in fatty tissues. However, challenges in extracting and characterizing RK and its associated phenolic compounds in fatty tissues persist due to the complex matrix effect. In this work, we reported a high-throughput sample preparation method for RK and 25 related phenolic compounds in white adipose tissues using an improved micro-scale QuEChERS (quick, efficient, cheap, easy, rugged and safe) approach with enhanced matrix removal (EMR)-lipid cleanup in 96-well plates, followed by UHPLC-QqQ-MS/MS analysis. The absolute recovery was 73-105% at the extraction step, and achieved 71-96% at the EMR cleanup step. The EMR cleanup removed around 66% of total lipids in the acetonitrile extract as profiled by UHPLC-QTOF-MS/MS. The innovative introduction of a reversed-phase C18 sorbent into the extract significantly improved the analytes' recovery during SpeedVac drying. The final accuracy achieved 80-120% for most analytes. Overall, this newly developed and validated method could serve as a powerful tool for analyzing RK and related phenolic compounds in fatty tissues.

Exposure of wild boars (Sus scrofa L) to neonicotinoid insecticides

The aim was to determine, for the first time, concentrations of 7 neonicotinoids (NEOs) and 5 metabolites in Sus scrofa from hunting areas in north-eastern Poland and assess the risk to consumers eating boar meat. 42 wild boar muscle samples were collected over a one-year period. The concentrations of 12 NEOs were determined by a fully validated LC-ESI-MS/MS protocol based on ultrasonic, freezing and cleanup EMR-lipid sample preparation. NEOs were present in over 83% of samples, 17% had no residue, and one pesticide was present in 36% of samples. Most often found were: clothianidin (35%), acetamiprid and imidacloprid (33%), thiacloprid (31%), thiamethoxam (9%), and the average concentrations were (ng g^-1): thiacloprid 6.2 > imidacloprid 5.7 > acetamiprid 4.6 > clothianidin 2.2 > thiacloprid 1.6 > thiamethoxam 1.0. Multi-residue samples were found, one with 7 and one with 5 NEOs. Two NEOs were present in 24%; 3 in 39% and 4 in 10% of samples. In the metabolic degradation of acetamiprid, imidacloprid and thiacloprid, it was observed that metabolites account for no more than 8.5% of the measured parent substance. Acetamiprid-n-desmethyl was noted most often (21%). Due to the detection of NEOs in a large proportion of samples, chronic and acute risk assessment were performed. The estimated chronic and acute risk for consumers from NEOs neonicotinoids through the consumption of wild boar was very low and amounted to respectively 0.02% of ADI and 0.86% of ARfD.

Comprehensive strategy for pesticide residue analysis in cocoa beans through qualitative and quantitative approach

Multiresidue quantitative and qualitative screening method for the analysis of pesticide residues in dried cocoa beans was validated and applied to imported and domestic cocoa beans samples. The quantitative method comprises of 15 pesticides while the screening method covers 110 pesticides of different chemical classes. The method was based on modified QuEChERS (Quick Easy Cheap Efficient Rugged Safe) extraction and detection using triple quadrupole (QQQ-MS) and ion mobility quadrupole time of flight mass spectrometry (IMS-QTOF). The method was quantitatively validated in terms of linearity, limit of quantification (LOQ), specificity, selectivity, accuracy, and precision. On the other hand, screening detection limits were established for 110 pesticides. Finally, the optimized strategy was successfully applied for the routine analysis of pesticide residues in 137 cocoa bean samples and 32% of the total samples were found positive for ametryn, chlorpyrifos, isoprocarb, and metalaxyl.

Human Exposures to Neonicotinoids in Kumasi, Ghana

Neonicotinoid insecticides (NNIs) are now popular in many agricultural systems across Africa; however, the extent of human exposures to NNIs in African countries is scarcely reported. The present study evaluates neonicotinoid exposures in the consumer population of Kumasi, a cosmopolitan city in Ghana. A total of 75 human urine samples were collected from healthy volunteers (nonfarmers, aged 13-80 yr) and analyzed with a liquid chromatography electrospray ionization tandem mass spectrometry system. Seven NNIs and 3 NNI metabolites were detected in the following pattern (frequency, median concentration, maximum concentration): N-dm-acetamiprid (94.7%, 0.41 µg/L, 8.79 µg/L) > imidacloprid (70.7%, 0.15 µg/L, 211.62 µg/L) > N-(6-chloro-3-pyridylmethyl)-N-ethyl-N'-methylformamidine (62.2%, 0.43 µg/L, 53.85 µg/L) > 2-[N-(6-chloro-3-pyridylmethyl)-N-ethylamino]-2-(methylimino)acetic acid (56.8%, 0.10 µg/L, 3.53 µg/L) > clothianidin (40%, >limit of quantification [LOQ], 0.45 µg/L) > nitenpyram (18.7%, >LOQ, 0.14 µg/L) ≈ thiamethoxam (18.7%, >LOQ, 0.21 µg/L) > dinotefuran (12.0%, >LOQ, 1.01 µg/L) > acetamiprid (2.7%, >LOQ, 0.08 µg/L) ≈ thiacloprid (2.7%, >LOQ, 0.14 µg/L). Approximately 92% of the subjects were found to be exposed to multiple neonicotinoids simultaneously. The mean, median, and maximum imidacloprid equivalent of the relative potency factor of NNIs were found to be 1.6, 0.5, and 22.52, respectively. The median estimated daily intakes of acetamiprid, imidacloprid, and nitenpyram were 0.47, 1.27, and 0.02 µg/kg/d for females and 0.91, 0.66, and 0.08 µg/kg/d for males, respectively. The maximum daily intakes of all the NNIs were <1% of their chronic reference doses (cRfDs), except for imidacloprid and thiacloprid which recorded maximum daily intakes corresponding to 17.97 and 8.28% of cRfDs, respectively. To the best of our knowledge, the present study is the first biomonitoring report on neonicotinoid insecticides in Africa. Environ Toxicol Chem 2021;40:2306-2318. © 2021 SETAC.

Z-sep+ based QuEChERS technique for the pre-concentration of malathion pesticide in fruits followed by analysis using UV-Vis spectroscopy

In this work, the concentrations of malathion in fruits were determined using UV-Vis spectrophotometry prior to pre-concentration using QuEChERS. The Z-sep⁺/PSA sorbent combination was used for the d-SPE clean-up and extraction was done using acetonitrile during QuEChERS. The absorbance of malathion was measured using a UV-Vis spectrophotometer at a wavelength of 415 nm. The QuEChERS parameters, which included type and volume of extraction solvent, type and mass of sorbents, and centrifugation rate, were optimised prior to application of the developed method to real fruit samples. The linear range was from 0.1 to 0.9 mg kg^-1 while the coefficient of determination (R²) was 0.9999. The limit of detection (LOD) for malathion was found to be 0.017 mg kg^-1 and the limit of quantification was 0.05 mg kg^-1. Orange samples were found to have no malathion residues when the developed method was applied to them while the concentrations of malathion in apple and pear samples were 0.07 mg kg^-1 and 0.09 mg kg^-1 respectively.

Cocoa Bean Shell-A By-Product with Nutritional Properties and Biofunctional Potential

Cocoa bean shells (CBS) are one of the main by-products from the transformation of cocoa beans, representing 10%‒17% of the total cocoa bean weight. Hence, their disposal could lead to environmental and economic issues. As CBS could be a source of nutrients and interesting compounds, such as fiber (around 50% w/w), cocoa volatile compounds, proteins, minerals, vitamins, and a large spectrum of polyphenols, CBS may be a valuable ingredient/additive for innovative and functional foods. In fact, the valorization of food by-products within the frame of a circular economy is becoming crucial due to economic and environmental reasons. The aim of this review is to look over the chemical and nutritional composition of CBS and to revise the several uses that have been proposed in order to valorize this by-product for food, livestock feed, or industrial usages, but also for different medical applications. A special focus will be directed to studies that have reported the biofunctional potential of CBS for human health, such as antibacterial, antiviral, anticarcinogenic, antidiabetic, or neuroprotective activities, benefits for the cardiovascular system, or an anti-inflammatory capacity.

Assessing dietary exposure risk to neonicotinoid residues among preschool children in regions of Taiwan

Neonicotinoids (NEOs) are a class of pesticides widely used worldwide. This study analyzed post-cooking residues of NEO pesticides and assessed their potential health risks for preschool children (0-6 years old) by conducting a total diet study (TDS). It involved food sampling, preparation, analysis of pesticide residues, estimation of food consumption data, and assessment of food safety risks. Food sampling was conducted between March and June 2015. A total of 128 food samples were obtained from 4 parts of Taiwan. After the food had been prepared, the 128 samples were aggregated into 32 composite food items and the NEO residues analyzed. Acetamiprid had the highest detection rate of the NEO residues (59.4%), and the concentrations ranged from not detected to 80.5 μg/kg. The estimated daily intake (EDI) of NEO residues among preschool children was found to be lower than the adjusted acceptable daily intake (ADI) even for highly exposed groups. The results showed that NEO pesticides were primarily detected in preserved fruits, cherry tomato, rape, bell fruit, and baby bok choy. The main health risk posed by detected NEO residues at high consumption rates for preschool children was attributed to acetamiprid (34.20 %ADI) and imidacloprid (23.69 %ADI), respectively. Therefore, this research implicates that the present level of NEO residues in the diets for preschool children in Taiwan does not exceed 100 %ADI.

Methodology development based on "dilute and shoot" and QuEChERS for determination of multiple mycotoxins in cocoa by LC-MS/MS

This work proposes an extraction method based on the "dilute and shoot" approach and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) for the simultaneous determination of 42 mycotoxins (34 quantified and 8 qualitatively studied) in dried cocoa bean samples. The purpose of the developed methodology was the reduction of co-extractives from the matrix and an efficient extraction without a cleanup step, and subsequent analysis by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). In order to obtain the best extraction conditions, gravimetric tests were performed and parameters that influenced the extraction efficiency were evaluated, such as the proportion of extraction phases, amount of salt, acidification, and extraction time. The performance of the developed method was evaluated to ensure its reliability. Considering the recovery range of 70-120% as an accuracy parameter, four of the mycotoxins under study (acetyl T-2, tenuazonic acid, wortmannin, and zearalenone) showed undesirable values at one of the levels evaluated. The repeatability of the method was assessed for 34 mycotoxins by the relative standard deviation (RSD%) of the responses, and all presented satisfactory values. The quantification limits ranged from 1.0 to 33.0 μg kg^-1. Modification of the extraction methods made it possible to simultaneously analyze multiple mycotoxins, eliminating the need for the cleanup step, which led to analyte losses. The proposed methodology has a low cost, which makes it advantageous in routine analysis. It also has the potential for scope extension to cocoa-based foods, which are naturally exposed to a greater variety of mycotoxins. Graphical abstract.

Simultaneous determination of eight neonicotinoid insecticides, fipronil and its three transformation products in sediments by continuous solvent extraction coupled with liquid chromatography-tandem mass spectrometry

Neonicotinoids (NEOs) and fipronil (FIP) are insecticides that are widely used in modern agriculture and have received considerable attention in recent years due to their adverse effects on non-target organisms in the environment. In the present study, a new method to simultaneously detect eight common NEO insecticides and FIP and its three transformation products (FIPs) in sediments was developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) based on a combined pretreatment of continuous solvent extraction (CSE) and solid phase extraction (SPE). Under optimized conditions, 5.0 g of freeze-dried sediment samples were initially extracted with methanol (20 mL)-methanol (15 mL)-water (20 mL) in sequence, and then the extract was cleaned with hydrophilic-lypophilic balance SPE cartridges, and HPLC-MS/MS analysis was conducted. The established method was validated to be sensitive, linear, accurate, and precise. The limits of detection (LOD) and limits of quantification (LOQ) of target compounds were 0.012-0.055 μg/kg d.w and 0.031-0.091 μg/kg d.w, respectively. Good linearity (R² > 0.990) was observed between 4.0 × 10^-2 and 20.0 μg/kg d.w. The recovery rates of all target insecticides were between 75.5% and 98.5%, and the relative standard deviations (RSD) were all less than 15.0% at the low, medium, and high spiked levels. Finally, the optimized method was applied to analyze 12 target insecticides in the sediments obtained from Jiaozhou Bay of China and its main inflow rivers. Acetamiprid, thiamethoxam, fipronil sulfide, and fipronil sulfone were detected in the river sediment samples at the concentration from <LOQ to 0.197 μg/kg d.w. Thus, the two types of studied insecticides can enter the sedimentary environment. Overall, the proposed method can be used to investigate the contamination status of typical NEOs and FIP insecticides in sediments and provide base data to comprehensively understand their environmental behavior, safety, and fate.

Assessing transfer of pesticide residues from chrysanthemum flowers into tea solution and associated health risks

Chrysanthemum (Dendranthema grandiflora) flowers are consumed as a popular, traditional herbal tea worldwide. During tea infusion with hot water pesticide residues in chrysanthemum flowers can be transferred into tea solution, posing potential health risks to consumers. Using greenhouse chrysanthemum this study systematically investigated the transfer of metalaxyl-M, fludioxonil, cyantraniliprole, thiamethoxam, and clothianidin (a major metabolite of thiamethoxam) from dry chrysanthemum flowers to tea solution at a range of infusion repetitions, duration and water temperature. The tested pesticides were released into tea solution at varying degrees, and the maximum transfer percentage was 59.9%, 9.8%, 29.4%, 88.2% and 68.4% for metalaxyl-M, fludioxonil, cyantraniliprole, thiamethoxam, and clothianidin, respectively. The transfer of pesticides into tea solution generally increased with increasing pesticide water solubility, water temperature, infusion duration, and pesticide concentrations in dry chrysanthemum flowers, but decreased with increasing octanol-water partition coefficient and the number of infusion repetitions. Risk quotient for pesticide intake via consuming tea solution of chrysanthemum flowers (one and two times of recommended pesticide dosages) ranged from <0.00003 to 0.0924, indicating a low health risk. This study provides useful information for risk assessment of pesticide residues in greenhouse chrysanthemum flowers and may help establish realistic maximum residue limit of pesticides in chrysanthemum flowers and tea solution.

Part-per-trillion LC-MS/MS determination of neonicotinoids in small volumes of songbird plasma

Neonicotinoids are the most widely used class of insecticides in the world, and there are increasing concerns about their effects on non-target organisms. Analytical methods to diagnose exposure to neonicotinoids in wildlife are still very limited, particularly for small animals such as songbirds. Blood can be used as a non-lethal sampling matrix, but the sample volume is limited by body size. Neonicotinoids have a low bioaccumulation potential and are rapidly metabolized, therefore, sensitive assays are critically needed to reliably detect their residues in blood samples. We developed an efficient LC-MS/MS method at a part-per-trillion (pg/ml) level to measure eight neonicotinoid related insecticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam) plus one metabolite (6-chloronicotinic acid) in small volumes (50 μL) of avian plasma. The average recovery of target compounds ranged from 95.7 to 101.3%, and relative standard deviations were between 0.82 and 2.13%. We applied the method to screen blood samples from 36 seed-eating songbirds (white-crowned sparrows; Zonotrichia leucophrys) at capture, and detected imidacloprid in 78% (28 of 36), thiamethoxam in 22% (8 of 36), thiacloprid in 11% (4 of 36), and acetamiprid in 11% (4 of 36) of wild-caught sparrows. 6 h after capture, birds were orally dosed with 0 (control), 1.2 or 3.9 mg of imidacloprid/kg bw, test results using this method indicated that plasma imidacloprid was significantly elevated (low 26-times, high 316-times) in exposed groups. This is the first study to confirm neonicotinoid exposure in small free-living songbirds through non-lethal blood sampling, and to demonstrate that environmentally realistic doses significantly elevate circulating imidacloprid concentrations. This sensitive method could be applied to characterize exposure to neonicotinoids in free-living wildlife and in toxicological studies.

Potential human exposures to neonicotinoid insecticides: A review

Due to their systemic character and high efficacy to insect controls, neonicotinoid insecticides (neonics) have been widely used in global agriculture since its introduction in early 1990. Recent studies have indicated that neonics may be ubiquitous, have longer biological half-lives in the environment once applied, and therefore implicitly suggested the increasing probability for human exposure to neonics. Despite of neonics' persistent characters and widespread uses, scientific literature in regard of pathways in which human exposure could occur is relatively meager. In this review, we summarized results from peer-reviewed articles published prior to 2017 that address potential human exposures through ingestion and inhalation, as well as results from human biomonitoring studies. In addition, we proposed the use of relative potency factor approach in order to facilitate the assessment of concurrent exposure to a mixture of neonics with similar chemical structures and toxicological endpoints. We believe that the scientific information that we presented in this review will aid to future assessment of total neonic exposure and subsequently human health risk characterization.

Determination of acetamiprid, imidacloprid, and spirotetramat and their relevant metabolites in pistachio using modified QuEChERS combined with liquid chromatography-tandem mass spectrometry

A QuEChERS based methodology was developed for the simultaneous identification and quantification of acetamiprid, imidacloprid, and spirotetramat and their relevant metabolites in pistachio by liquid chromatography-tandem mass spectrometry for the first time. First, sample extraction was done with MeCN:citrate buffer:NaHCO₃ followed by phase separation with the addition of MgSO₄:NaCl. The supernatant was then cleaned by a primary-secondary amine (PSA), GCB, and MgSO₄. The proposed method provides a linearity in the range of 5-200µgL^-1, and the linear regression coefficients were higher than 0.99. LOD and LOQ were obtained to be 2 and 5µgkg^-1 for the studied insecticides, respectively, with the exception of imidacloprid-olefin (5 and 10µgkg^-1). Acceptable recoveries (91-110%) were obtained for all the analytes with good intra- and inter-precisions (0.4≥RSD ≤11.0). The method was then used for the pistachio samples collected from a field trial to estimate the maximum residue limits (MRLs) in next step.

Simultaneous Analysis of Ursolic Acid and Oleanolic Acid in Guava Leaves Using QuEChERS-Based Extraction Followed by High-Performance Liquid Chromatography

In this paper, a novel method of QuEChERS-based extraction coupled with high-performance liquid chromatography has been developed for the simultaneous determination of ursolic acid (UA) and oleanolic acid (OA) in guava leaves. The QuEChERS-based extraction parameters, including the amount of added salt, vortex-assisted extraction time, and absorbent amount, and the chromatographic conditions were investigated for the analysis of UA and OA in guava leaves. Under the optimized conditions, the method showed good linearity over a range of 1-320 μg mL^-1, with correlation coefficients above 0.999. The limits of detection of UA and OA were 0.18 and 0.36 μg mL^-1, respectively. The intraday and interday precision were below 1.95 and 2.55%, respectively. The accuracies of the UA and OA determinations ranged from 97.4 to 111.4%. The contents of UA and OA in the guava leaf samples were 2.50 and 0.73 mg g^-1, respectively. These results demonstrate that the developed method is applicable to the simultaneous determination of UA and OA in guava leaves.