A new sustainable filtration membrane extraction method based on nanoconfined liquid phase extraction: Determination of organochlorinated pesticides and pyrethroids in tea samples.

BACKGROUND: Pesticides are used in agricultural production for prevent and control crop diseases and pests, but it is easy to cause excessive pesticides residues in agricultural products, polluting the environment and endangering human health. Due to their unmatched and sustainable capabilities, nanoextraction procedures are becoming every day more important in Analytical Chemistry. In particular, nanoconfined liquid phase extraction has shown extraction capabilities toward polar, medium polar, and/or nonpolar substances, which can be easily modulated depending on the nanoconfined solvent used. Furthermore, this "green" technique showed excellent characteristics in terms of recoveries, extraction time (≤1 min), reliability, and versatility. (97) RESULTS: In this work, the advantages of this technique have been coupled with those of filtration membrane extraction, making use of carbon nanofibers (CnFs) growth on carbon microspheres (CµS). This substrate has been deposited on a filter, which combined with gas chromatographic mass spectrometry (GC-MS) analysis successfully employed for the nanoextraction of 30 pesticides (18 organochlorine and 12 pyrethroids) in tea samples. Under the optimized extraction conditions, the linear range with standard solutions was from 1 to 1000 ng mL-1 (R2 ≥ 0.99), the limit of detections in tea samples were in the range 0.56-17.98 µg kg-1. The accuracy of the developed method was evaluated by measuring the extraction recovery of the spiked tea samples, and recoveries between 74.41 % and 115.46 %. (119) SIGNIFICANCE: Considering the versatility of nanoconfined liquid phase extraction and the functionality of the filtration membrane extraction procedure, this new extraction method can be considered a powerful candidate for automatized high-throughput analyses of real samples. (34).

A novel honeycomb-like 3D-printed device for rotating-disk sorptive extraction of organochlorine and organophosphorus pesticides from environmental water samples.

In this study, 3D-printing based on fused-deposition modeling (FDM) was employed as simple and cost-effective strategy to fabricate a novel format of rotating-disk sorptive devices. As proof-of-concept, twenty organochlorine and organophosphorus pesticides were determined in water samples through rotating-disk sorptive extraction (RDSE) using honeycomb-like 3D-printed disks followed by gas chromatography coupled to mass spectrometry (GC-MS). The devices that exhibited the best performance were comprised of polyamide + 15 % carbon fiber (PA + 15 % C) with the morphology being evaluated through X-ray microtomography. The optimized extraction conditions consisted of 120 min of extraction using 20 mL of sample at stirring speed of 1100 rpm. Additionally, liquid desorption using 800 µL of acetonitrile for 25 min at stirring speed of 1100 rpm provided the best response. Importantly, the methodology also exhibited high throughput since an extraction/desorption platform that permitted up to fifteen simultaneous extractions was employed. The method was validated, providing coefficients of determination higher than 0.9706 for all analytes; limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.15 to 3.03 µg L-1 and from 0.5 to 10.0 µg L-1, respectively. Intraday precision ranged from 4.01 to 18.73 %, and interday precision varied from 4.83 to 20.00 %. Accuracy was examined through relative recoveries and ranged from 73.29 to 121.51 %. This method was successfully applied to analyze nine groundwater samples from monitoring wells of gas stations in São Paulo. Moreover, the greenness was assessed through AGREEprep metrics, and an overall score of 0.69 was obtained indicating that the method proposed can be considered sustainable.

Validation and Evaluation of Selected Organic Pollutants in Shrimp and Seawater Samples from the NW Portuguese Coast.

The development of coastal regions has contributed to the intensification of environmental contamination, which can accumulate in aquatic biota, such as shrimps. These crustaceans, besides being delicious and being a good source of nutrients, can also accumulate environmental pollutants. Amongst others, these include organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs) and synthetic musks (SMs). These pollutants, classified as endocrine disruptors, are related to adverse effects in humans and since one of the major routes of exposition is ingestion, this is a cause for concern regarding their presence in food. The aim of the present study was to quantify the presence of environmental pollutants in shrimp samples and in the water from their habitat along the northwest Portuguese coast. In seawater samples, only two OCPs (lindane and DDD) and one BFR (BTBPE) were detected, and in shrimp samples, one OCP (DDD) and three SMs (HHCB, AHTN and ketone) were found. Bioaccumulation and the risk assessment of dietary exposure of SMs in shrimp samples were investigated. It was observed that all shrimp samples analyzed significantly presented bioaccumulation of the three SMs found. Concentrations of SMs detected in shrimp samples do not present a health risk for the adult Portuguese population.

Exploring the use of cork pellets in bar adsorptive microextraction for the determination of organochloride pesticides in water samples with gas chromatography/electron capture detection quantification.

In this study, a biosorbent material with characteristics for the adsorption of organic compounds was used for a cork pellet-based bar adsorptive microextraction technique, as a new greener alternative for the determination of organochlorine compounds. Aldrin, chlordane, dieldrin, endrin, lindane, 4,4-DDD, 4,4-DDE, 4,4-DDT, α-endosulfan and ß-endosulfan were analyzed in water samples (drinking water, stream water and river water) with separation/detection by gas chromatography and electron capture detection (GC/ECD). The parameters that can affect the sample preparation efficiency such as desorption solvent and time as well as extraction time and ionic strength were evaluated by multivariate and univariate designs. Cork pellets (10  ×  Ø 3 mm) were used for the extraction of 15 mL of sample in the optimal conditions: 60 min of agitation with no salt added to the sample, followed by desorption of the cork pellet with 120 µL of ethyl acetate for 30 min. The bar-to-bar RSD out with five different bars showed good results with RSD ≤ 15.6%, allowing the use of simultaneous extractions. LOD and LOQ values ranged from 3 to 15 ng L-1 and 10 to 50 ng L-1 respectively, and the determination coefficients were greater than 0.9869. The target analytes were not detected in the three analyzed samples. Therefore, the recovery study was performed fortifying the water samples. Analyte recovery ranged from 48.7 - 138.2% for drinking water, 40.2 - 128.2% for stream water and 67.5 - 128.7% for river water.

A three-phase solvent extraction system combined with deep eutectic solvent-based dispersive liquid-liquid microextraction for extraction of some organochlorine pesticides in cocoa samples prior to gas chromatography with electron capture detection.

A sample pretreatment method based on the combination of a three-phase solvent extraction system and deep eutectic solvent-based dispersive liquid-liquid microextraction has been introduced for the extraction of four organochlorine pesticides in cocoa samples before their determination by gas chromatography-electron capture detection. A mixture of sodium chloride, acetonitrile, and potassium hydroxide solution is added to cocoa bean or powder. After vortexing and centrifugation of the mixture, the collected upper phase (acetonitrile) is removed and mixed with a few microliters of N,N-diethanol ammonium chloride: pivalic acid deep eutectic solvent. Then it is rapidly injected into deionized water and a cloudy solution is obtained. Under optimum conditions, the limits of detection and quantification were found to be 0.011-0.031 and 0.036-0.104 ng/g, respectively. The obtained extraction recoveries varied between 74 and 92%. Also, intra- (n = 6) and interday (n = 4) precisions were less than or equal to 7.1% for the studied pesticides at a concentration of 0.3 ng/g of each analyte. The suggested method was applied to determine the studied organochlorine pesticide residues in various cocoa powders and beans gathered from groceries in Tabriz city (Iran) and aldrin and dichlobenil were found in some of them.

Validation of ultrasonic-assisted switchable solvent liquid phase microextraction for trace determination of hormones and organochlorine pesticides by GC-MS and combination with QuEChERS.

QuEChERS and switchable solvent liquid phase microextraction (SS-LPME) were respectively used as pretreatment and preconcentration tools to allow trace determination of selected organochlorine pesticides and hormones by gas chromatography mass spectrometry (GC-MS). The effects of principal SS-LPME variables and their interactions were evaluated with a Box-Behnken experimental design. The limits of detection obtained by direct GC-MS determination were enhanced by about 33-115 folds under the optimized SS-LPME conditions. The SS-LPME method was applied to tap water, well water, lake water, medical wastewater and tea samples. Satisfactory recovery results were obtained for all but the tea samples using the conventional calibration plot. Matrix matched calibration standards were used to improve the percent recovery of analytes to almost 100% in the tea samples. The combined QuEChERS and SS-LPME method was applied to tomato samples and matrix matching was also used to significantly improve analyte recoveries.

Triazine-based porous organic framework as adsorbent for solid-phase microextraction of some organochlorine pesticides.

Triazine-based porous organic frameworks (POFs) were constructed through a Friedel-Crafts reaction of cyanuric chloride (CC) with triphenylamine (TPA) monomers. The obtained POFs (CC-TPAs) were explored as the solid-phase microextraction (SPME) fiber coatings for the extraction of the organochlorine pesticides (OCPs). It was found that the mesoporous volume of the CC-TPAs was the main factor for their SPME adsorption performance. The CC-TPA-based fiber was successfully used for the SPME of the OCPs from fruit samples (apple, peach and pear). With the help of gas chromatography-micro-electron capture detection, the CC-TPA-based SPME method showed high enrichment factors (146-456), low limits of detection (0.032-0.090 ng g-1), good linearity (0.11-20 ng g-1, r2 > 0.991) and satisfactory repeatability (relative standard deviations <10.5%) for the OCPs. The method recoveries for spiked OCPs at the concentrations of 0.5, 2.0 and 10.0 ng g-1 in fruit samples were in the range of 86.0-114.0%, 83.5-116.5% and 81.1-118.6%, respectively. The CC-TPA coated fiber was stable enough for 100 extraction cycles without significant loss of the extraction efficiency.

Removal of organochlorines from vegetable oils and its benefits in preventing formation of monochloropropanediol diesters.

This paper reports the first results on depleting certain organochlorines from vegetable oils without the use of any solvent in order to mitigate monochloropropanediol diesters (MCDPE). The concept is based on separating the organochlorines from the bulk oil by using trapping agents (e.g. monoacylglycerols) that can be easily separated from the oil. The process starts by mixing and homogenizing crude vegetable oils with the trapping agent and subsequently separating the trapping agent from the oil bulk via crystallization. The proof-of-concept of the approach is demonstrated on a spiked sunflower model system, solvent extracted crude sunflower oil, industrially produced crude soybean and corn oils. The depletion of organochlorines in the crude oils and its beneficial effect on the MCPDE content in the heat treated samples is measured by LC-MS. The depletion efficacy of the monitored organochlorines was estimated to be in the 60-95 % range. Both the melting point and polarity of the trapping agents affected the depletion efficacy of the organochlorines. Trapping agents with higher melting point and polarity, such as monostearin were more effective in comparison to high melting point but less polar agents such as palm stearin or agents rich in polar but low melting point monolinolein/monoolein. The effect of organochlorine depletion on the subsequent MPCDE levels in heat treated oil was in the range of 60-90 % reduction depending on the type of the studied oil.

A Case Study of Natural Attenuation of Chlorinated Solvents Under Unstable Groundwater Conditions in Takahata, Japan.

The natural attenuation behavior of chlorinated solvents and their risks to human health at a contaminated groundwater site in Takahata, Japan, were investigated. It was found that volatile organic compound (VOC) concentrations gradually decreased via two attenuation mechanisms, namely dilution and biodegradation. It was estimated that the VOC concentrations will be below the Japanese limits within 30 years after stopping the active remediation in 2003, which suggests that there is a high possibility that monitored natural attenuation can be adopted as the clean-up method at this contaminated site. The risk levels of VOCs at the present time are much lower than those at the time when the contamination was discovered. Vinyl chloride still presents a risk in some wells, and there were occasional unexpected increases in the risk levels of tetrachloroethylene, trichloroethylene, and cis-1,2-dichloloethylene, which means that continuous monitoring of the groundwater is necessary for forecasting risk levels.

Impacts and interactions of organic compounds with chlorine sanitizer in recirculated and reused produce processing water.

Water conservation and economics dictate that fresh produce processors reuse/recirculate the process water. However, the ensuing accumulation of organic matter in water depletes the chlorine sanitizer required for food safety. In this study, we comprehensively investigated chemical compounds that are responsible for water quality in relation to chemical oxygen demand (COD) and chlorine demand (CLD), the two most critical factors associated with water treatment and chlorine replenishment. Simulating commercial fresh-cut wash operations, multiple batches of diced cabbage (0.3 x 0.3 cm2) were washed in the same tank of water. The major components were isolated from the wash water and analyzed by HPLC. Sugars were the predominant compounds (82.7% dry weight) and the major contributor to COD (81.6%), followed by proteins/peptides (7.3% dry weight, 5.3% COD), organic acids (6.2% dry weight, 3.6% COD), and phenolics (0.5% dry weight, 0.5% COD). By repeated time course measures, the effect of these chemicals on CLD are dependent on the chemical structure, concentration in the wash water, and their rate of reaction. Proteins/peptides accounted for about 50% of the total CLD over a 120-min period and phenolics was 21% at 5 min, but diminished with time. The contribution by organic acids and sugars increased continuously, reaching 22% and 16% of total CLD at 120 min of chlorination, respectively. Collectively, these compounds represented 86% of the CLD in cabbage wash water at 5 min and greater than 94% CLD afterwards. This is the first systematic report on the source of COD and CLD during fresh produce washing. It provides essential information for the produce processors to develop safe, effective, and economical wash water treatment/reuse and chlorine replenishment strategies.

Preparation of porous zinc ferrite/carbon as a magnetic-assisted dispersive miniaturized solid phase extraction sorbent and its application.

In this study, porous ZnFe2O4/carbon, derived from Zn-Fe zeolitic imidazolate framework (Zn-Fe-ZIF), was employed as a novel sorbent for magnetic-assisted dispersive miniaturized solid phase extraction (M-DµSPE). The Zn-Fe-ZIF derived magnetic porous ZnFe2O4/carbon was easily prepared using a one-pot solvothermal method, and its morphology, structure and magnetic characteristics were evaluated via scanning electron microscopy, powder X-ray diffraction, Raman spectroscopy and vibrating sample magnetometry. The extraction ability of ZnFe2O4/carbon is evaluated by different kinds of compounds including organochlorine pesticides, pyrethroid insecticides, aldehydes, nerolidol, benzoic acid and sorbic acid. A M-DµSPE method was developed for the analysis of organochlorine pesticides. Several parameters affecting the extraction efficiency were systematically investigated. The calibration curves ranged from 0.05 to 100 ng g-1 and the limits of detection were 0.005-0.3 ng g-1. The intra-day and inter-day relative standard deviations were lower than 2.3 and 5.2%. The recoveries of spiked organochlorine pesticides were in the range of 86.1-109.4%.

Enrichment and physiological responses of dechlorane plus on juvenile marine macroalgae (Ulva pertusa).

Dechlorane Plus (DP), a chlorinated flame retardant, is increasingly reported in aquatic ecosystems worldwide. But little information is available regarding the toxicity of DP in marine organisms, especially in macroalgae. The objective of this study was to investigate effects of DP exposure on photosynthesis, oxidative stress and its enrichment in juvenile marine macroalgae (Ulva pertusa). Following 21- day uptake and 21- day depuration (10-8 mol/L), algae accumulated 1.18 times of DP compared to the initial concentration. Anti-DP was prone to accumulate in juvenile macroalgae. The enrichment of DP affected the physiological responses in algae. After 1, 7 and 14 days DP exposure (10-8, 10-7 and 10-6 mol/L), antioxidant enzymes (SOD and CAT) activities and MDA content changed in a dose and time depended manner. Chlorophyll fluorescence parameters, including Fv/Fm, ΦPSII and ETR decreased with the increasing DP concentration. It indicated that DP leads to a low rate of light energy utilization in algae which may ascribe to the oxidative damage induced by DP enrichment. Present study provides insight into the toxicological effects of DP on marine macroalgae, which is useful for risk assessment of DP in intertidal zone ecosystems.

Hyper-crosslinked polymer nanoparticles as the solid-phase microextraction fiber coating for the extraction of organochlorines.

A hyper-crosslinked polymer benzenedimethanol (HCP-BDM) was synthesized and explored as a solid-phase microextraction (SPME) fiber coating material. To prepare the HCP-BDM, 1,4-benzenedimethanol monomer was self-condensed via a simple Friedel-Crafts alkylation reaction. The physical-chemical properties of the HCP-BDM material were characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric and analysis nitrogen adsorption-desorption isotherms. The HCP-BDM coated fiber demonstrated excellent adsorption performance for some organochlorine pesticides (OCPs). An effective HCP-BDM fiber-based SPME method combined with gas chromatography-micro electron capture detector was established for the analysis of the OCPs from various vegetable samples. The linear ranges were observed from their corresponding limits of quantification (LOQs) to 50 ng g-1 for the OCPs, with correlation coefficients varied from 0.9952 to 0.9992. Their limits of detection at S/N = 3 ranged from 0.058 to 0.14 ng g-1. The single fiber repeatability and fiber-to-fiber reproducibility, expressed as the relative standard deviations (RSDs), were from 3.4% to 8.8% and from 6.7% to 9.6%, respectively. The established method was finally applied to the analysis of the OCPs from cucumber, Chinese cabbage and tomato samples with satisfactory recoveries and repeatability.

Characterization of a Prenyltransferase for Iso-A82775C Biosynthesis and Generation of New Congeners of Chloropestolides.

Chloropupukeananin and chloropestolides are novel metabolites of the plant endophyte Pestalotiopsis fici, showing antimicrobial, antitumor, and anti-HIV activities. Their highly complex and unique skeletons were generated from the coisolated pestheic acid (1) and iso-A82775C (10) based on our previous studies. Here, we identified the biosynthetic gene cluster iac of 10 and characterized an iacE encoded prenyltransferase. Deletion of iacE abolished iso-A82775C production, accumulated the prenyl group-lacking siccayne (2), and generated four new chloropestolides (3-6). Compounds 5 and 6 showed antibacterial effects against Staphylococcus aureus and Bacillus subtilis, and 5 was also cytotoxic to human tumor cell lines HeLa, MCF-7, and SW480. These results provided the first genetic and biochemical insights into the biosynthesis of natural prenylepoxycyclohexanes and demonstrated the feasibility for generation of diversified congeners by manipulating the biosynthetic genes of 10.

Easy and fast extraction methods to determine organochlorine pesticides in sewage sludge, soil, and water samples based at low temperature.

Organochlorine pesticides present in sewage sludge can contaminate soil and water when they are used as either fertilizer or agricultural soil conditioner. In this study, the technique solid-liquid extraction with low temperature purification was optimized and validated for determination of ten organochlorine pesticides in sewage sludge and soil samples. Liquid-liquid extraction with low temperature purification was also validated for the same compounds in water. Analyses were performed by gas chromatography-mass spectrometry operating in the selective ion monitoring mode. After optimization, the methods showed recoveries between 70% and 115% with relative standard deviation lower than 13% for all target analytes in the three matrices. The linearity was demonstrated in the range of 20 to 70 µg L-1, 0.5 to 60 µg L-1, and 3 to 13 µg L-1, for sludge, soil, and acetonitrile, respectively. The limit of quantification ranged between 2 and 40 µg kg-1, 1 and 6 µg kg-1, and 0.5 µg L-1 for sludge, soil, and water, respectively. The methods were used in the study of pesticide lixiviation carried out in a poly vinyl chlorine column filled with soil, which had its surface layer mixed with sludge. The results showed that pesticides are not leached into soil, part of them is adsorbed by the sewage sludge (4-40%), and most pesticides are lost by volatilization.

A novel chloro-substituted pentenamide from the fruiting bodies of Amanita virgineoides.

One unusual chloro-substituted pentenamide, (3R)-4-chloro-3-hydroxy-4-pentenamide (1), together with 11 known compounds (2-12) were isolated from the fruiting bodies of Amanita virgineoides. The structure of 1 including the absolute configuration was characterized by extensive spectroscopic analyses and quantum calculation. Compound 1 displayed no obvious activity against herpes simplex virus (HSV), human enterovirus 71 (EV71) or coxsackievirus B3 (CVB3).

Isolation, Synthesis, and Biological Activity of Chlorinated Alkylresorcinols from Dictyostelium Cellular Slime Molds.

Eight chlorinated alkylresorcinols, monochasiol A-H (1-8), were isolated from the fruiting bodies of Dictyostelium monochasioides. Compounds 1-8 were synthesized to confirm their structures and to obtain sufficient material for performing biological tests. Monochasiol A (1) selectively inhibited the concanavalin A-induced interleukin-2 production in Jurkat cells, a human T lymphocyte cell line. Monochasiols were biogenetically synthesized by the combination of biosynthetic enzymes relating to the principal polyketides, MPBD and DIF-1, produced by Dictyostelium discoideum.

Lepistatins A-C, chlorinated sesquiterpenes from the cultured basidiomycete Lepista sordida.

Three new chlorinated sesquiterpenes, named lepistatins A-C, were isolated from the culture broth of Basidiomycete Lepista sordida. The structures were determined by the analysis of spectroscopic data including HREIMS and 1D and 2D NMR. The absolute configuration of lepistatin B was determined by comparing the specific rotation and circular dichroism spectrum with those of known structurally related compounds bearing the same chiral carbon. The structures of lepistatins A-C feature the indanone core structure, but differ from other indanone-containing sesquiterpenes of fungal origin by the alkyl substitution pattern. This indicates that lepistatins A-C probably possess a new sesquiterpene scaffold derived from the common precursor, trans-humulyl cation, by an alternative cyclization.

Partitioning of hydrophobic organic contaminants between polymer and lipids for two silicones and low density polyethylene.

Polymers are increasingly used for passive sampling of neutral hydrophobic organic substances (HOC) in environmental media including water, air, soil, sediment and even biological tissue. The equilibrium concentration of HOC in the polymer can be measured and then converted into equilibrium concentrations in other (defined) media, which however requires appropriate polymer to media partition coefficients. We determined thus polymer-lipid partition coefficients (KPL) of various PCB, PAH and organochlorine pesticides by equilibration of two silicones and low density polyethylene (LDPE) with fish oil and Triolein at 4 °C and 20 °C. We observed (i) that KPL was largely independent of lipid type and temperature, (ii) that lipid diffusion rates in the polymers were higher compared to predictions based on their molecular volume, (iii) that silicones showed higher lipid diffusion and lower lipid sorption compared to LDPE and (iv) that absorbed lipid behaved like a co-solute and did not affect the partitioning of HOC at least for the smaller molecular size HOC. The obtained KPL can convert measured equilibrium concentrations in passive sampling polymers into equilibrium concentrations in lipid, which then can be used (1) for environmental quality monitoring and assessment, (2) for thermodynamic exposure assessment and (3) for assessing the linkage between passive sampling and the traditionally measured lipid-normalized concentrations in biota. LDPE-lipid partition coefficients may also be of use for a thermodynamically sound risk assessment of HOC contained in microplastics.

Dispersive solid-phase extraction for the determination of trace organochlorine pesticides in apple juices using reduced graphene oxide coated with ZnO nanocomposites as sorbent.

In this work, reduced graphene oxide coated with ZnO nanocomposites was used as an efficient sorbent of dispersive solid-phase extraction and successfully applied for the extraction of organochlorine pesticides from apple juice followed by gas chromatography with mass spectrometry. Several experimental parameters affecting the extraction efficiencies, including the amount of adsorbent, extraction time, and the pH of the sample solution, as well as the type and volume of eluent solvent, were investigated and optimized. Under the optimal experimental conditions, good linearity existed in the range of 1.0-200.0 ng/mL for all the analytes with the correlation coefficients (R2 ) ranging from 0.9964 to 0.9994. The limits of detection of the method for the compounds were 0.011-0.053 ng/mL. Good reproducibilities were acquired with relative standard deviations below 8.7% for both intraday and interday precision. The recoveries of the method were in the range of 78.1-105.8% with relative standard deviations of 3.3-6.9%.