Beta-cypermethrin (beta-CP), an important pyrethroid insecticide, and its main acid metabolites are frequently detected in human samples. Because beta-CP may pose some risk to human health, we studied dynamics and residues of beta-CP and its metabolites in hen egg, droppings, blood, and 15 other tissues after continuous exposure. A digestive model was then used to study beta-CP’s digestive fate. Beta-CP and its metabolites significantly accumulated in tissues with high lipid contents and were readily transferred to eggs. Beta-CP was mainly metabolized into acid metabolites that accumulated in egg and edible tissues of laying hens, suggesting that humans may be exposed to beta-CP acid metabolites through food.Keywords: beta-cypermethrin; digestion; laying hens; metabolites; residue;

Pyrethroids and the metabolites have been frequently observed in the environment. Animal data suggests that pyrethroids can induce adverse effect on the cardiovascular system but there are no human studies examining pyrethoids exposure as a risk for coronary heart disease (CHD). We analyzed three nonspecific pyrethroids metabolites in urine and studied the association with CHD risk. A total of 72 CHD patients and 136 healthy subjects were recruited in Shanxi province in China from 2013 to 2014 by matching age and gender. The median concentrations of urinary cis-CDDA (cis-3-(2,2-dichlorovinyl)-2,2-dimethyl cyclopropane carboxylic acid), trans-CDDA (trans-3-(2,2-dichlorovinyl)-2,2-dimethyl cyclopropane carboxylic acid) and 3-PBA (3-phenoxybenzoic acid) among healthy subjects were 1.03, 0.42, 0.74 μg/L respectively, while the median concentrations of the three metabolites among CHD patients were 1.93, 1.07, 1.09 μg/L respectively, significantly higher than healthy subjects. Upper tertile of urinary pyrethroid metabolites were associated with an increased risk of CHD compared with the lowest tertile (cis-CDDA: ORT3vsT1 = 6.86, 95% CI: 2.76–17.06, p-trend = 0.000; trans-CDDA: ORT3vsT1 = 6.94; 95% CI: 2.80–17.19; p-trend =0.000; 3-PBA: ORT3vsT1 = 3.62; 95% CI: 1.48–8.88; p-trend = 0.009; total pyrethroid metabolites: ORT3vsT1 = 4.55; 95% CI: 1.80–11.54; p-trend = 0.002). This study provides information on pyrethroids exposure in China and reveals a possible positive association between pyrethroids exposure and the risk of coronary heart disease.

α-Hexachlorocyclohexane (α-HCH) is a chiral organochlorine pesticide that is often ubiquitously detected in various environmental matrices and may be absorbed by the human body via food consumption, with serious detriments to human health. In this study, enantioselective degradation kinetics and residues of α-HCH in laying hens were investigated after a single dose of exposure to the pesticide, whereas enantioselectivity and residues of α-HCH in eggs, droppings, and various tissues were investigated after long-term exposure. Meanwhile, montmorillonite (MMT), a feed additive with high capacity of adsorption, was investigated for its ability to remove α-HCH from laying hens. Most non-brain tissues enantioselectively accumulated (−)-α-HCH, while (+)-α-HCH was preferentially accumulated in the brain. The enantiomer fractions (EFs) in most tissues gradually decreased, implying continuous depletion of (+)-α-HCH in laying hens. After 30 days of exposure and 31 days of elimination, the concentration of α-HCH in eggs and tissues of laying hens with MMT-containing feed was lower than that with MMT-free feed, indicating the removal effects of MMT for α-HCH in laying hens. The findings presented herein suggest that modified MMT may potentially be useful in reducing the enrichment of α-HCH in laying hens and eggs, thus lowering the risk of human intake of α-HCH.

•The carboxymethyl-β-cyclodextrin functionalized magnetic adsorbents were synthesized.•The adsorbents could capture or release quaternary ammonium herbicides by changing pH.•The adsorbents were applied in the analysis of real water samples.•There is no attendance of organic solvents in the whole analysis process.In our work, the pH-controlled magnetic solid phase extraction for the determination of paraquat and diquat was introduced firstly. Furthermore, to clarify the mechanism of carboxymethyl-β-cyclodextrin functionalized magnetic adsorbents, we studied the pH-responsive supramolecular interaction between carboxymethyl-β-cyclodextrin (CM-β-CD) and paraquat/diquat by ultraviolet–visible (UV–vis) spectroscopy and nuclear magnetic resonance (NMR) experiment, and the energy-minimized structures were also obtained. Then, the functional group CM-β-CD was modified on the surface of magnetic materials to synthesize the adsorbent. The Fourier transform infrared spectrum (FT-IR) results proved the successful modification of CM-β-CD. Thus, this absorbent was applied for the determination of paraquat and diquat in water. Under the optimal condition, limits of detection (LODs) of paraquat and diquat were 0.8 μg L−1 and 0.9 μg L−1, relative standard deviations (RSD) and recoveries varied 0.7–4.6% and 86.5–106.6%, respectively. Good recoveries (70.2–100.0%) and low RSD (1.7–9.6%) were achieved in analyzing spiked water samples. Furthermore, with the capillary electrophoresis (CE) as the analyser, the whole analytical process did not need the attendance of organic solvents.

The enantioselective degradation of the widely used chiral insecticide α-cypermethrin in soils has been investigated, and its main metabolites cis-3-(2′,2′-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA) and 3-phenoxybenzoic acid (3-PBA), which have potential environmental problems, have also been determined. The enantiomers of α-cypermethrin were separated on Chiralcel OD chiral columns by high-performance liquid chromatography (HPLC) under normal phase, and the metabolites were detected by gas chromatography (GC) after derivatization. The results of the degradation showed that α-cypermethrin dissipated in soils with relatively long half-lives of 12.70–47.08 days and obvious stereoselective degradation of the two enantiomers was observed in the five soils, with enantiomeric fraction (EF) from 0.55 to 0.61 after 42 days, indicating that (+)-(1R,cis,αS) enantiomer was preferentially degraded. cis-DCCA and 3-PBA were formed in all of the soils, and it was found that the amount generated was related to the soil pH. cis-DCCA was easily generated in the acidic soils, while more 3-PBA tended to be generated in the soil of pH over 7. To evaluate the impact on soil animals, the toxicity, including the combined toxicity of cis-DCCA, 3-PBA, and α-cypermethrin, to earthworm (Eisenia fetida) was studied. The results of enantioselective transformation of α-cypermethrin in soils and the toxicity of α-cypermethrin and its metabolites to earthworm have some implications for environmental risk and food safety evaluations.

A simple and inexpensive sample pretreatment method, ultrasound-assisted liquid phase microextraction, combined with a novel solvent layering technique, was developed for extraction of organochlorine pesticides from soil. Samples were analyzed by gas chromatography with an electron capture detector. Of five possible extraction solvents tested, xylene, with a density of 0.86 g mL−1, was selected for further method development. Soil samples and solution were mixed in an ultrasonic water bath and separated using centrifugation. The extraction solvent was collected on the solution surface using a pipette. Parameters, such as extraction solvent type and volume, extraction time, and NaCl concentration were optimized. Under optimal conditions, recoveries ranged from 71.6% to 114.6% and correlation coefficients ranged from 0.9961 to 0.9996. Detection limits, calculated as 3× the signal-to-noise ratio, were from 0.04 to 0.18 μg L−1. The standard deviations ranged from 6.7% to 19.6%.

•A novel effervescent tablet composed of citric acid, sodium bicarbonate and 1-undecanol (extraction solvent) was made in a simple way.•The effervescence assisted on-site liquid phase microextraction has been developed for extracting triazine herbicides in environmental waters.•This method can extract many samples in a short time.•This method has been successfully applied in the analysis of water samples in the field.A novel effervescence assisted on-site liquid phase microextraction has been developed for the determination of five triazine herbicides in water. The use of an effervescent tablet composed of citric acid, sodium bicarbonate and 1-undecanol (extraction solvent) was the core of the method. The triazine herbicides in water were extracted by 1-undecanol released from tablet under effervescence and determined by ultra-high pressure liquid chromatography tandem mass spectrometer. The experimental variables, including NaCl concentration, temperature, weight of effervescent tablet, volume of extraction solvent and pH value, were screened by a Plackett–Burman design and optimized by a Box–Behnken design. Under the optimized conditions, good linearity was obtained in the range of 0.05–10 μg L−1 with correlation coefficients ranging from 0.9936 to 0.9988. The limits of quantification were between 7.6 and 26.4 ng L−1, and the recoveries were in 71.4–93.2% with relative standard deviations of 2.5–10.9%. This method, which does not require centrifugation and any special apparatus, was successfully applied to determine triazine herbicides in real waters, promising to be a way to speed field sampling procedures for the organic pollutants monitoring in water.

A novel sample pre-treatment technique termed dispersive suspended microextraction (DSME) coupled with gas chromatography-flame photometric detection (GC-FPD) has been developed for the determination of eight organophosphorus pesticides (ethoprophos, malathion, chlorpyrifos, isocarbophos, methidathion, fenamiphos, profenofos, triazophos) in aqueous samples. In this method, both extraction and two phases’ separation process were performed by the assistance of magnetic stirring. After separating the two phases, 1 μL of the suspended phase was injected into GC for further instrument analysis. Varieties of experiment factors which could affect the experiment results were optimized and the following were selected: 12.0 μL p-xylene was selected as extraction solvent, extraction speed was 1200 rpm, extraction time was 30 s, the restoration speed was 800 rpm, the restoration time was 8 min, and no salt was added. Under the optimum conditions, limits of detections (LODs) varied between 0.01 and 0.05 μg L−1. The relative standard deviation (RSDs, n = 6) ranged from 4.6% to 12.1%. The linearity was obtained by five points in the concentration range of 0.1–100.0 μg L−1. Correlation coefficients (r) varied from 0.9964 to 0.9995. The enrichment factors (EFs) were between 206 and 243. In the final experiment, the developed method has been successfully applied to the determination of organophosphorus pesticides in wine and tap water samples and the obtained recoveries were between 83.8% and 101.3%. Compared with other pre-treatment methods, DSME has its own features and could achieve satisfied results for the analysis of trace components in complicated matrices.Graphical abstract.Highlights► A novel technique termed dispersive suspended microextraction has been developed. ► Varieties of experiment factors which would affect the experiment results were optimized and selected. ► Compared with other LPME, the most difference is that the restoration step instead of centrifugation process. ► In this technique, the experiment process was divided into two critical steps: the extraction step and the restoration step. ► In the final experiment, this method has been successfully applied in the analysis of wine and tap water samples.

A novel sample pre-treatment technique, based on vortex-assisted surfactant-enhanced-emulsification liquid–liquid microextraction (VSLLME), followed by gas chromatography-flame photometric detection (GC-FPD) has been developed for the determination of seven organophosphorus pesticides (OPPs) in wine and honey samples. In the VSLLME method, the extraction solvent was dispersed into the aqueous samples by the assistance of vortex agitator. Meanwhile, the addition of a surfactant, which was used as an emulsifier, could enhance the speed of the mass-transfer from aqueous samples to the extraction solvent. The main parameters relevant to this method were investigated and the optimum conditions were established: 15 μL chlorobenzene was used as extraction solvent, 0.2 mmol L−1 Triton X-114 was selected as the surfactant, the extraction time was fixed at 30 s, 3% sodium chloride was added and the extraction process was performed under the room temperature. Under the optimum conditions, limits of detections (LODs) were varied between 0.01 and 0.05 μg L−1. The relative standard deviation (RSD, n = 6) ranged from 2.3% and 8.9%. The linearity was obtained by five points in the concentration range of 0.1–50.0 μg L−1. Correlation coefficients (r) varied from 0.9969 to 0.9991. The enrichment factors (EFs) were in a range of 282–309. Finally, the proposed method has been successfully applied to the determination of target analytes in real samples. The recoveries of the target analytes in wine and honey samples were between 81.2% and 108.0%.

The stereoselective pharmacokinetics of flutriafol were investigated in male and female adult Japanese white rabbits. Following intravenous administration of rac-flutriafol to rabbits at 5 mg/kg (bd wt), the concentrations of the enantiomers in plasma were determined by a HLPC-UV method using a CDMPC-CSP chiral column. R-Flutriafol exhibited a shorter distribution half-life but a longer elimination half-life than the S-isomer. In female rabbits, the distribution half-lives of R- and S-flutriafol were found to be 0.09 and 0.18 h, respectively, significantly shorter than those in male rabbits, but the volume of distribution and elimination half-life for flutriafol enantiomers in both sexes of rabbit showed no significant differences. Female rabbits had a higher clearance for both flutriafol enantiomers. The protein binding value was high for both isomers, with enantioselectivity, but no gender difference. It was an important factor in modulating the disposition of flutriafol. Flutriafol concentrations in kidney, liver, fat, and lung were higher than in other tissues at 10 h after administration, and the concentrations of R-flutriafol were higher in all tissues than those of its antipode. However, gender difference in flutriafol residues in tissues was not observed. It is concluded that the stereoselectivity of flutriafol on distribution and elimination in rabbits mainly depends upon gender.

•α-cypermethrin and its metabolites of cis-DCCA and 3-PBA had been detected in the bullfrog organs in the experiments of oral administration and water exposure.•The enantioselective degradation of α-cypermethrin in bullfrog organs was conducted in this paper.•Detection method of α-cypermethrin, cis-DCCA and 3-PBA in bullfrog organs were validated.Bullfrog, as a kind of amphibians, can be easily exposed to varied pollutants in the environment for the reason of its habitats and highly permeable skin. We investigated the degradation kinetics and residues of α-cypermethrin in bullfrog by two different methods of administration for the environmental monitoring the behavior of one of the most used pesticides in the amphibians. The oral administration and water exposure of α-cypermethrin on bullfrog was studied in this work. α-Cypermethrin and its main metabolites of cis-3-(2′,2-dichlorovinyl)−2,2-dimethylcyclopropane carboxylic acid (cis-DCCA) and 3-phenoxybenzoic acid (3-PBA), which have been determined that having correlation with a number of epidemic diseases, were detected simultaneously. The method for residue analysis in the bullfrog's organs was validated. The average recoveries for α-cypermethrin were ranged from 71.7% to 100.3% and the limit of quantification was 0.005 mg/kg. The average recoveries of its metabolites at levels between 0.002 and 0.5 mg/kg ranged between 77.9% and 102.4% with a limit of quantification of 0.002 mg/kg. Furthermore, the enantiomers of α-cypermethrin were separated on gas chromatograph (GC) equipped with a chiral column of BGB-172 and the metabolites were detected by gas chromatography (GC) after derivatization. After exposure of α-cypermethrin on bullfrog, the enantioselective degradation behavior was observed and its metabolites were detected in bullfrog tissues. The dynamic trends of α-cypermethrin and its metabolites were fitted to a two-compartment model except 3-PBA fitting to one-compartment model in skin. Concentration of α-cypermethrin and its metabolites in bullfrog's organs increased and reached an equilibrium state during water exposure of α-cypermethrin. Liver and kidney were the major organs for α-cypermethrin and its metabolites retention in both experiments.Download high-res image (188KB)Download full-size image

•A new low-density magnetofluid dispersive liquid–liquid microextraction (LMF-DMMLE) method was developed.•Various experimental factors were optimized and selected.•This method has been successfully applied in the analysis of real water samples.A new micro-extraction technique named low-density magnetofluid dispersive liquid–liquid microextraction (LMF-DMMLE) has been developed, which permits a wider range of solvents and can be combined with various detection methods. Comparing with the existing low density solvents micro-extraction methods, no special devices and complicated operations were required during the whole extraction process. Dispersion of the low-density magnetofluid into the aqueous sample is achieved by using vortex mixing, so disperser solvent was unnecessary. The extraction solvent was collected conveniently with an external magnetic field placed outside the extraction container after dispersing. Then, the magnetic nanoparticles were easily removed by adding precipitation reagent under the magnetic field. In order to evaluate the validity of this method, ten organochlorine pesticides (OCPs) were chosen as the analytes. Parameters influencing the extraction efficiency such as extraction solvents, volume of extraction solvents, extraction time, and ionic strength were investigated and optimized. Under the optimized conditions, this method showed high extraction efficiency with low limits of detection of 1.8–8.4 ng L−1, good linearity in the range of 0.05–10.00 μg L−1 and the precisions were in the range of 1.3–9.6% (RSD, n = 5). Finally, this method was successfully applied in the determination of OCPs in real water samples.Download full-size image