Gas Chromatography-electron Capture Detection Research Articles

IMPACT OF DECONTAMINATION PROCESSES ON THE REDUCTION OF PESTICIDE RESIDUES IN GREEN CHILLI

This study has been designed to determine the extent of pesticide residue removal from chilli fruits through common household practices. One time foliar application of quinalphos, profenophos, ethion, cyhalothrin, imidacloprid, and acetamiprid was done as a tank mix at recommended doses at 50% fruit formation stage. Samples were collected after 48 hr of spray, subjected to various decontamination treatments, and analysed using the validated QuEChERS method employing GC-ECD (Gas Chromatograph Electron capture detector), and Liquid Chromatograph Tandem Mass Spectrometer (LC-MS/MS). Compared to all the treatments, soaking in 5% acetic acid for one min was found to be most effective in the removal of quinalphos (23.68%), profenophos (19.47%), ethion (23.33%), and cyhalothrin (25.00%). The next best treatment was found to be soaking for one min in lukewarm water, which removed 20-30% of quinalphos, ethion, cyhalothrin, and acetamiprid residues.

Detection of organochlorine pesticides in estuarine sediments of protected wetlands in Taiwan using high‐resolution gas chromatography/high‐resolution mass spectrometry and gas chromatography‐electron capture detector

AbstractTrace residues of organochlorine pesticides (OCPs) in estuarine surface sediments were investigated at three protected wetlands in southern Taiwan using high‐resolution gas chromatography/high‐resolution mass spectrometry (HRGC/HRMS) and gas chromatography‐electron capture detector (GC‐ECD). This study facilitates the development of new strategies for investigating OCPs, particularly at background levels. Linear relationships were obtained between total OCP concentrations (∑OCP), as analyzed by HRGC/HRMS, and the sediment's total organic carbon (TOC) and water content. It contrasted with the results acquired by GC‐ECD, where no significant relationship was found. GC‐ECD is a rugged option for daily routine practice, particularly in cases of patterns yielded by GC‐ECD is clear; the HRGC/HRMS method provides more reliable qualitative and quantitative capabilities and is highly recommended for studying the fate of OCPs and carrying out risk assessments. The average ∑OCP of these three wetlands by HRGC/HRMS was found in a range of 0.214 to 1.049 ng/g dry weight. The highest OCP level might be attributed to associated irrigation systems receiving massive discharges of domestic sewage from an urban area upstream of the wetland. The ratio of dichlorodiphenyltrichloroethane (DDT) to its metabolites indicated that the DDT residue in these areas was from aged input. According to sediment quality guidelines, adverse ecotoxicological effects of OCPs upon sediments were not expected in these protected wetlands.

Dissipation kinetics, risk assessment, and waiting period of spiromesifen on chili fruits using gas chromatography-electron capture detector.

A supervised field trial was designed in Rajasthan Agricultural Research Institute, Durgapura, Jaipur, Rajasthan, to assess the dissipation and persistence of spiromesifen in chili fruits. Spiromesifen (22.9% suspension concentrate) was sprayed two times at an interval of 10 days at the recommended dose (96 g. a.i. ha-1 ) and double the recommended dose (192 g. a.i. ha-1 ) with four replications. Sampling was done according to the planned interval of days after the second spray. Extraction and cleanup were performed using the modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and the spiromesifen residue was analyzed by GC-electron capture detector and confirmation performed using GC-MS. The average initial deposit of spiromesifen was 1.207 mg kg-1 and 1.948 mg kg-1 at the recommended and double the recommended dose, respectively. The half-life values of spiromesifen ranged between 2.7 and 3.2 days at the recommended and double the recommended dose. The safe waiting period was calculated for the respective doses and it was concluded that an average of 7 days is safe for picking. The FSSAI (Food Safety and Standards Authority of India) have set the maximum residue limit of 0.1 mg kg-1 for spiromesifen in green chili. The theoretical maximum residue contribution value of spiromesifen was lower than the maximum permissible intake at both the applications on the 0th day. Hence, there will be no adverse effects on human health after consumption of green chilies.

Persistence and dissipation kinetics of novaluron 9.45% + lambda-cyhalothrin 1.9% ZC insecticides in tomato crop under semi-arid region.

In recent decades, fate studies of pesticides have been a topic of interest worldwide due to human health concerns tomato, contain abundant nutritional phytochemicals and lycopene which is known for antioxidant. Tomato is susceptible to many pest, so to overcome from these pests many insecticides are used, leaving residual effects on the crop. So to find out the persistence, the present study was carried out to investigate the residual levels and dissipation behaviour of novaluron 9.45% + lambda-cyhalothrin 1.9% ZC in tomato crop during Rabi session of 2017-18 in randomized block design. The first spray of insecticide was done at fruit formation stage and second spray at 10-day interval at recommended dose @43.31ga.i.ha-1 and double of recommended dose @86.62ga.i.ha-1. The residue of novaluron determined by HPLC (high-performance liquid chromatography) on 0day (two hours after spraying) was 0.154ppm at lower dose and 0.234ppm at higher dose. The residue of lambda-cyhalothrin determined by GC ECD (gas chromatography electron capture detector) at 0day (two hours after spraying) was 0.451ppm at lower dose and 0.849ppm at higher dose. The deposition of novaluron 9.45% + lambda-cyhalothrin 1.9% ZC was gradually decreased with increasing days after spraying (DAS). The mean initial deposition of the pesticide novaluron and lambda-cyhalothrin was recorded as 0.154mg/kg, 0.451mg/kg, respectively, at the recommended dose @43.31ga.i.ha-1 while at double of recommended dose @86.62ga.i.ha-1 novaluron and lambda-cyhalothrin, the mean initial deposition of 0.234mg/kg and 0.849mg/kg was recorded, respectively. The residue of the novaluron and lambda-cyhalothrin was at BDL (below determination level) (0.01 and 0.05ppm) on 5th and 7th day, respectively, at lower dose (x), whereas at higher dose (2x) it was below determination level on 7th and 10th day, respectively. In soil samples, the residue levels were at below the determination level (0.01mg/kg) for novaluron and (0.05mg/kg) for lambda-cyhalothrin at both doses. The half-life DT50 of novaluron and lambda-cyhalothrin in the tomato fruit was found to be 2days at recommended dose (X) @43.31ga.i.ha-1 for both the pesticide and at double of the recommended dose @86.62g a.i. ha-1 it was 3 and 2days, respectively.

Quantitative determination of bromochloroacetamide in mice urine by gas chromatography combined with salting-out assisted dispersive liquid-liquid microextraction.

Bromochloroacetamide (BCAcAm) is the main haloacetamide (HAcAm) detected in drinking water in different regions and exhibits strong cytotoxicity and genotoxicity. However, there is no appropriate method for detecting BCAcAm in urine or other biological samples, and thus, the internal exposure level in the population cannot be accurately assessed. In this study, a gas chromatography-electron capture detector (GC-ECD) was combined with salting-out assisted dispersive liquid-liquid microextraction (SA-DLLME) to develop a rapid and robust method for BCAcAm detection in urine of mice continuously exposed to BCAcAm. The factors influencing the pre-treatment procedure, including the type and volume of extraction and disperser solvents, extraction and standing time, and the amount of salt, were evaluated systematically. Under the optimised conditions, the analyte achieved good linearity in the spiked concentration range of 1.00-400.00 μg L-1, and the correlation coefficient was higher than 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.17 μg L-1 and 0.50 μg L-1, respectively. The recoveries ranged from 84.20% to 92.17%. The detection of BCAcAm at three different calibration levels using this method afforded an intra-day precision of 1.95-4.29%, while the inter-day precision range was 5.54-9.82% (n = 6). This method has been successfully applied to monitor the concentration of BCAcAm in mouse urine in toxicity experiments and can provide technical support for assessing human internal exposure levels and health risks in later studies.

Magnetic cork composites as biosorbents in dispersive solid-phase extraction of pesticides in water samples.

This study assessed the use of magnetic biosorbents in dispersive solid-phase extraction with a gas chromatograph-electron capture detector for the determination of trifluralin, chlorothalonil, transfluthrin, bromopropylate, and bifenthrin in water samples. To our knowledge, this is the first time that magnetic cork composites are used as an adsorbent in dispersive solid-phase extraction. The advantages of magnetic cork composites include their density regulation and high surface areas. The magnetic composites can be recovered using a magnetic field for desorption purposes, which can improve the operation process and reduce the extraction time. Moreover, the parameters affecting the extraction performances were optimized. The method has a limit of detection between 0.30 and 2.02 μg L-1. Good linearities (R2 > 0.99) were obtained in the linear range of 1.00 to 2000 μg L-1. The relative recoveries of the analytes in tap water, river, and lake water samples spiked at different concentrations ranged between 90% and 104%, and the relative standard deviations were less than 7.1%. Therefore, this study showed that Fe3O4/cork magnetic composites can be used as efficient and eco-friendly biosorbents in dispersive solid-phase extraction for the determination of pesticides in water samples. The use of these composites contributes to the current trend of green chemistry.

Groundwater recharge and dating in crystalline basement aquifers of Vea catchment: An integrated environmental tracers’ approach

The crystalline basement aquifers host significant groundwater resources for the communities in Vea catchment for public and irrigational water supply. As part of measures to understand the hydrogeological processes of the area, multi-tracers (SF6, CFC-12, CFC-11, 3H, δ18O and δ2H) were employed to elucidate the groundwater residence time, recharge mechanism and mixing process of the shallow groundwater. Ambient concentrations of these tracers were taken from 10 sampling locations in the Vea catchment of Upper East Region of Ghana. A purge and trap method was used to take the samples and electron capture detector gas chromatography (GC-ECD) was used to analytically measure the SF6 and CFCs gases in the groundwater. The SF6, CFC-11 and CFC-12 dating complimented with 3H revealed that the groundwater age in the catchment was relatively young ranging from 5 to 42 years with a mean age of 23 years. This corroborates well with the stable isotopes data , which showed that the catchment receives modern recharge from meteoric origin. The results also indicated that the estimated SF6 ages were younger compared to the CFCs ages, suggesting additional inputs of SF6 from terrigenous sources. Similarly, a comparison of 3H and CFCs showed little variations in ages in some wells, a possible indication of CFCs degradation. The conceptual groundwater flow model developed showed three groundwater flow regimes along the topographical line. Despite some uncertainties in age interpretations, the multi-environmental tracers have been successfully used to date shallow groundwater in the Vea catchment. To reduce the uncertainties in the age determination, the use multi tracer approach is highly recommended.

Toxicokinetics and edible tissues-specific bioaccumulation of decabrominated diphenyl ethers (BDE-209) after exposure to the broilers

Decabromodiphenyl ether (BDE-209), the primary constituent of a widely used flame retardant formulation, is often present in high levels in avian derived products and could be transferred to humans through consumption. The purpose of this study was to investigate the toxicokinetics and bioaccumulation patterns of BDE-209 in different tissues of broilers, which would benefit the evaluation of chicken product safety. Male broilers received a single oral administration of BDE-209 at 25 mg/kg.BW and then BDE-209 concentrations in the plasma, liver, leg muscle, breast muscle, and other tissues were measured using gas chromatography-electron capture detection (GC-ECD). The changes of BDE-209 concentrations in the plasma were fitted to a non-compartmental model for kinetic analysis. Peak values were observed at 24 h (t1/2 =168.28 h), and trace levels remained for four weeks. Additionally, Cmax in the liver was much higher than that in leg and breast muscles, and Tmax from the liver and muscle were 12 and 24 h, respectively. Residual BDE-209 was detected in all broiler tissues after 2 weeks, and concentrations were ranked as follows: fat > liver > thymus gland > heart > testis > thigh muscle > skin > lung > kidney > breast muscles > spleen (wet weight (ww)). Our results suggested that BDE-209 was widely distributed in different tissues after intestinal absorption, and preferentially accumulated in adipose and liver tissues. Observations of bioaccumulation and slow elimination in the liver and muscles provide critical insight into the toxicity of BDE-209 and risk assessment of edible tissues from broilers.

Development of a polyurethane-coated thin film solid phase microextraction device for multi-residue monitoring of pesticides in fruit and tea beverages.

A novel solid-phase microextraction device coated with an efficient and cheap thin film of polyurethane was developed for trace determination of 13 widely used pesticides in fruit and tea beverages. A round-shaped polyurethane film covering the bottom of a glass vial was fabricated as the sorbent to exhibit a superior capacity for preconcentrating target compounds and reducing matrix interferences. After optimization of the key parameters including the film type, extraction time, solution pH, ionic strength, desorption solvent, and conditions, this device allowed an efficient adsorption-desorption cycle for the pesticides accomplished in one vial. Coupled with gas chromatography-electron capture detection, the polyurethane-coated thin film microextraction method was successfully established and applied for the analysis of real fruit and tea drinks, showing low limits of detection (0.001-0.015μg/L), wide linear ranges (1.0-500.0μg/L, r2 >0.9931), good relative recoveries (77.2%-106.3%) and negligible matrix effects (86.1%-107.5%) for the target pesticides. The proposed approach revealed strong potential of extending its application by flexibly modifying the type or size of the coating film. This study provides insights into the enrichment of contaminants from complex samples using inexpensive and reusable microextraction devices that can limit the environmental and health impact of the sample preparation protocol.

Construction of a ringent multi-shelled hollow MIL-88B as the solid-phase microextraction fiber coating for the extraction of organochlorine pesticides

In this work, a ringent multi-shelled hollow MIL-88B (RMH-MIL-88B) was prepared from the original MIL-88B via etching by citric acid, and was used as the fiber (SPME) coating material for the direct-immersion solid-phase microextraction of eleven organochlorine pesticides (OCPs) from fish samples prior to gas chromatography-electron capture detection. The unique multi-shelled structure with void space between shells enables the RMH-MIL-88B to provide more adsorption sites and to have larger adsorption capacities for the OCPs than the original MIL-88B. Under the optimized experimental conditions, a wide linear range (from 3.3 to 600.0 ng g−1) with the coefficients of determination (r2) varying from 0.9960 to 0.9997 was obtained. The limits of detection (S/N of 3) for the analytes were in the range of 1.0–3.0 ng g−1. In the determination of the analytes, the single fiber repeatability (n = 5) by single RMH-MIL-88B-coated fiber ranged from 4.1 % to 7.6 %, while the fiber-to-fiber reproducibility by five parallel RMH-MIL-88B-coated fibers were in the range of 8.0 %–12 %. The established method was successfully applied for the sensitive determination of the eleven OCPs in four fish samples (grass carp, crucian carp, tilapia, and mandarin fish). The relative recoveries of the analytes for spiked fish samples at three concentration levels (15.0, 80.0 and 300.0 ng g−1) were in the range of 82.11 %–115.7 % with the relative standard deviations of 4.4 %–12 %.

Miniaturized kapok fiber-supported liquid extraction for convenient extraction of pesticide residues in vegetable oils: Determination of organochlorine pesticides as a proof-of-concept study

In this paper, a miniaturized kapok fiber-supported liquid extraction (mini-KF-SLE) method was proposed for selective extraction of pesticide residues in vegetable oils. The natural kapok fiber was used as an inert oil support material based on its hydrophobic and lipophilic properties, and the extraction device was conveniently constructed by loading 15 mg of kapok fiber at the lower middle part of a 1-mL pipette tip. The vegetable oil sample (150 mg) without any pretreatment was directly loaded, followed by the addition of 150 μL of acetonitrile (ACN) as the extractant. After static extraction for 30 min, the extractant was pipetted out with a pipettor. As the proof of concept, it was applied for extracting eight organochlorine pesticides (OCPs) from vegetable oils and the eluate was analyzed by gas chromatography-electron capture detector (GC-ECD). Under optimized conditions, the extraction recoveries of OCPs were calculated to be in ranges of 35.8–79.5%. The satisfied quantitation ability was verified by the established method with coefficients of determination (R2) being greater than 0.99. The limits of detection (LODs) were in ranges of 2.0–50.0 ng/g. The relative recoveries were in ranges of 78.3–117.0% with the inter-/intra-day relative standard deviation (RSD) both being less than 13.3%. The potential of mini-KF-SLE to extract other kinds of pesticides was further verified by the successful extracting three triazole pesticides in vegetable oils with good extraction recoveries (>41.4%). The proposed mini-KF-SLE in combination with instrument detection techniques has the great potential in the low-cost and high-throughput determination of various pesticide residues in vegetable oils.

Adverse Effects of Organochlorine Pesticide Residues on Biochemical Parameters and Oxidative Stress in Libyan Agricultural Workers

Agricultural workers are in danger of being exposed to toxic substances such as pesticides. To estimate the individual danger of handling pesticides, the bio-monitoring of effects on agricultural workers is required. There has been no such research previously conducted among Libyan agricultural workers. This research was designed to study the biochemical parameters impacts of the pesticide contamination among Libyan agricultural workers at Aljebal Alakhtar, Libya. 45 blood samples were taken from male agriculture workers at Aljebal Alakhtar who had been exposed to pesticides in crop fields for a long time, while 25 blood samples were taken from a group of people who had not been exposed to pesticides (control). Kits were used to assess plasma ALT, AST, ALP, GST, SOD, total protein, albumin, globulin, total bilirubin, total cholesterol, triglycerides, HDL-C, LDL-C, VLDL-C, urea, and creatinine. The thiobarbituric acid reactive substances (TBARS) assay was used to evaluate lipid peroxidation in serum. Using a gas chromatography-electron capture detector, the blood samples were tested for organochlorine pesticide residues (GC-ECD). In comparison to controls, workers had significantly higher SOD, GST, ALP, AST, and ALT activities, as well as higher levels of lipid profile, total bilirubin, creatinine, and urea, as well as significantly higher TBARS concentrations. Furthermore, long-term pesticide exposure was also related to reduceing total protein, albumin, and globulin, as well as reduced HDL-C levels. Pesticide exposure seems to influence various biochemical markers in general. These biomarkers appear to be indicative of pesticide-related deleterious effects in agricultural workers, indicating that they should be used for routine monitoring of impacts.

Determination of fipronil and its metabolites in environmental water samples by meltblown nonwoven fabric-based solid-phase extraction combined with gas chromatography-electron capture detection.

In this study, a new method for the determination of fipronil and its three metabolites in environmental water samples was developed based on meltblown nonwoven fabric solid-phase extraction combined with gas chromatography-electron capture detection. As the core material of medical masks, meltblown nonwoven fabric is made of polypropylene superfine fibers which are randomly distributed and bonded together with a relatively large specific surface area and good permeability. Polypropylene as a high molecular hydrocarbon-based polymer has the characteristics of good hydrophobicity and lipophilicity, which can be applied for the separation and enrichment of hydrophobic substances in food, environment, and biological samples. The meltblown nonwoven fabric is soft and can fill the solid-phase extraction cartridge tightly. This aspect also makes it suitable to be used as an ideal solid-phase extraction sorbent. A series of parameters influencing the extraction efficiency were investigated, and under the optimized conditions, fipronil and its three metabolites had a good linear relationship in the range of 0.2-100 μg/L with a correlation coefficient R2 of more than 0.999. The recoveries at three spiked concentrations were in the range of 99.2-107.3% with the relative standard deviations less than 9.8% (intra-day) and 8.1% (inter-day). The limit of detection for the four target analytes was in the range of 0.02-0.06μg/L. Finally, this method was successfully applied in the analysis of fipronil and its three metabolites in various types of environmental water samples.

Dispersive liquid–liquid microextraction-assisted by deep eutectic solvent for the extraction of different chlorophenols from water samples followed by analysis using gas chromatography-electron capture detection

A deep eutectic solvent (DES) was prepared using o-cresol and acetic acid as hydrogen bond acceptor and hydrogen bond donor, respectively, and used for the simultaneous extraction of different chlorophenols from water samples. With dispersive liquid–liquid microextraction based on the solidification of DES (DLLME-DES), different key parameters including the type of dispersing solvent, the effect of pH, volume of DES, and dispersing solvent, as well as the volume of the derivatization reagent were investigated to reach the maximum extraction efficiency. The limits of detection and quantification were in the range of 0.015–1.0 µg/L and 0.05–3.0 µg/L, respectively. Chlorophenols recoveries from water samples spiked at different concentration levels were 32–91% (RSD ≤ 5.8%). Satisfactory repeatability values were 1.7–5.8% through analyzing seven replicates of chlorophenols standards at concentration levels of monochlorophenols 200 µg/L, dichlorophenols 100 µg/L, trichlorophenols 4.0 µg/L, tetrachlorophenols, and pentachlorophenols 2.0 µg/L.

On-site sample pretreatment: Natural deep eutectic solvent-based multiple air-assisted liquid–liquid microextraction

Chemical protection is one of the most important methods to control forest pests. Since pesticides used in chemical protection might have significant adverse effects on aquatic organisms, it is essential to monitor and detect trace pesticides in environmental water. In this study, an on-site natural deep eutectic solvent-based multiple air-assisted liquid–liquid microextraction coupled with gas chromatography-electron capture detection was developed for determining triadimefon, bifenthrin, bromopropylate, and permethrin in water samples in the forest. A series of menthol-based deep eutectic solvents were synthesized for the first time to find green and efficient extractants. Moreover, a deep eutectic solvent with a 1:2 molar ratio of DL-menthol to citric acid was selected as the extractant due to its high stability and extraction performance. A portable modular array device based on air-assisted liquid–liquid microextraction was designed and manufactured to enable the simultaneous pretreatment of several samples. Although no electric equipment is required throughout the process, up to six samples were pretreated on-site within 20 min. Moreover, the average sample pretreatment time was less than 3.5 min, and the process was substantially simplified and enhanced. In addition, the parameters affecting the extraction performance were optimized. The extraction recoveries were in the range of 92–95% by using the optimized conditions, and the relative standard deviations of the intra-device, inter-device, intra-day, and inter-day factors were all less than 4.9%. The detection limits of the method ranged from 0.34 to 3.3 µg L−1. Good linearities (R2>0.999) were shown in the linear range of 1.13 to 2500 µg L−1 for the studied pesticides. Moreover, the proposed method was proved to be highly environmentally friendly by the Analytical Eco-Scale and Green Analytical Procedure Index. In summary, the proposed method is green, efficient, and flexible for on-site water sample pretreatment. The fact that tedious operations can be converted into standard operations provides a new perspective for on-site sample processing.

Organochlorine and Organophosphorus Pesticides Residues in Commercial Poultry Feed Samples in Lagos State, Nigeria

Pesticides are among Persistent Organic Pollutants (POP) used in agricultural practices to increase production efficiency. They enter the food chain, bioaccumulate and are toxic to human, animals and the environment. The presence of pesticide residues in animal feeds has been rarely monitored and reported in Nigeria. This study evaluated the levels of pesticide residues in different brands and types of poultry feeds that are produced, marketed and used in Lagos, Nigeria. Five types of five commonly used commercial brands (25 samples) of poultry feeds were purchased from animal feed markets in Lagos, Nigeria. Simultaneous detection and quantitation of selected thirteen (13) OCPs and eight (8) OPs residues in the feeds was carried out using Gas Chromatography-Electron Capture Detector (GC-ECD) and Gas Chromatography-Flame Ionization Detector (GC-FID) respectively. Results revealed that all the feed samples had multiple pesticide residues levels which ranged from 0.10 - 1.83 mg/kg for OCPs and 0.25 - 6.04 mg/kg for OPs. These values were above the Maximum Residual Limit (MRL). The detected pesticide residues order of violation of the MRL was Methoxychlor > Dieldrin >Endrin ketone for OCPs, and Trichlorfon > Malathion > Diazinon for OPs. There was no significant (p>0.05) differences in the pesticide residues levels among the brands and types of the samples. Present study indicates extensive and unwholesome use of pesticides in the agro industry in Nigeria suggesting need to enforce Good Agricultural Practices (GAP), Good Storage Practices (GSP), Good Manufacturing Practices (GMP) and constant monitoring of pesticide residues thereby implementing the Good health and Wellbeing (Goal 3) of the 2030 Sustainable Development Goal.

Impact of pesticide residues (chlorpyrifos, cypermethrin, profenophos) on health and liver marker values alkaline phosphate (ALP), alanine amino transferase (ALT) and (AST) among workers of pesticide formulation & packing plants in Pakistan

Objective: To evaluate the impact of pesticide residues (chlorpyrifos, cypermethrin, profenophos) on health and liver marker values alkaline phosphate (ALP), aspartate amino transferase (AST) and alanine amino transferase (ALT) among workers of pesticide formulation & packaging plants in Pakistan Materials and Methods: A hundred workers of the age group between 20-50 years working, for at least a year, at various pesticide formulation & packaging units were included in the present study. One hundred workers, apparently healthy, with no history of pesticide exposure - after matching age, sex and social status - were taken as control. Biochemical tests ALP, AST and ALT, were carried out using chemistry autoanalyzer, Dimension RXL (Dade Behring). Pesticide residues (chlorpyrifos, cypermethrin, profenophos) were carried out employing gas chromatograph electron capture detector GCECD 2010, Shimadzu Japan. Results: In current study 100 workers of pesticide industry were taken and ALP, AST and ALT of 80 workers out of 100 were found to be within the normal limits. However, 20 workers had unusually raised levels of ALP ALT and AST. These twenty workers showed pesticide residues of chlorpyrifos, cypermethrin, profenopos in their blood. Conclusions: the pesticide residual level of all the workers were very low (below the no observable adverse affect level NOAEL) and were not too significant to create health problems. Key Words: Pesticide industrial workers; Residue; Serum; Enzymes

Novel N-riched covalent organic framework for solid-phase microextraction of organochlorine pesticides in vegetable and fruit samples

A covalent organic framework named N-COF was successfully constructed by the aldehyde-amine condensation reaction between 2,4,6-tris (4-formyl phenoxy)-1,3,5-triazine and 1,3-bis(4-aminophenyl) urea for the first time. The prepared N-COF exhibited good stability and high affinity to organochlorine pesticides (OCPs). Thus, the N-COF was served as solid phase microextraction fiber coating for extraction of six OCPs from vegetables and fruits including romaine lettuce, cabbage, Chinese cabbage, apple, pear and peach, followed by quantitation with gas chromatography-electron capture detector (GC-ECD). Under the optimal conditions, good linearities for the OCPs existed in the ranges from 0.1 to 1.0 ng g−1 to 100.0 ng g−1 for the samples. The low limits of detection for analytes were obtained in the range of 0.03–0.3 ng g−1. The present work can offer new alternative for sensitive analysis of trace level of OCPs in vegetables and fruits.

An environmental friendly and stable analytical method for the determination of indicator polychlorinated biphenyls (PCBs) in solid and waste oil samples by gas chromatography-electron capture detector (GC-ECD)

This study presents the optimization and comprehensive verification studies of a stable analytical method for the determination of seven indicator polychlorinated biphenyls (PCBs) in solid and waste oil samples by using gas chromatography-electron capture detector (GC-ECD). In extraction method optimization, the maximum efficient and environmentally compatible extraction conditions were obtained at 30 mL hexane:acetone (3:1) use and 1.25 min solvent hold time. In validation studies, this method indicated an excellent linearity from 50 μg/L to 500 μg/L since the correlation coefficients higher than 0.9975 for all PCBs. The LOD values varied from 10.1 μg/L to 10.3 μg/L and the LOQ values ranged from 33.7 μg/L to 45.5 μg/L. The mean recoveries in soil, sewage sludge and waste oil varied as 85.6–97.7 %, 82.8–91.2 %, and 96.2–108.8 %, respectively. The intra-day precision (RSD, (%) in soil, sewage sludge and waste oil varied as 3.73–6.33 %, 3.72–8.91 %, and 1.37–5.44 %, respectively, whereas the inter-day precision (RSD, (%)) in sewage sludge changed from 2.35 to 9.74 %. In trueness, both results from CRMs (the recovery of PCBs varied 84.3 % to 114.4 %) and PTs (z-scores for indicator PCBs varied from (−0.5 to 1.65) demonstrate that this method possesses well enough and sufficient capability for the rapid, selective, and correct determination of indicator PCBs in soil and waste oil samples. There was no critical ME (recovery varied from 82.6 to 99.5 % in all matrices) and the RSD (%) values for each matrices was below 6 %. In the measurement uncertainty, the expanded uncertainties (µg/kg) of seven indicator PCBs changed from 3.50 to 4.38. The contributions from the sample preparation (45.19–53.83 %), the calibration curve (20.34–27.04 %) and the repeatability (11.80–18.02 %) were the major sources to the expanded uncertainty. In real samples, eleven sewage sludge, two soil, and twenty-seven waste oil samples had results above the LOQ for at least one indicator PCB.

Efficient solid-phase microextraction of twelve halogens-containing environmental hormones from fruits and vegetables by triazine-based conjugated microporous polymer coating

A triazine-based conjugated microporous polymer (TCMP) was generated by introduced 1, 3, 5-triazine into conjugated microporous polymer network via Friedel-Crafts reaction. Under the optimum synthesis conditions, the obtained TCMP has a loose and porous structure. It was then used as a fiber coating material for solid-phase microextraction (SPME) of halogens-containing environmental hormones. It showed a strong adsorption capability due to the halogen bond, electrostatic, π-π stacking and hydrophobicity interactions. An analytical method combining the TCMP coated fiber-based SPME with gas chromatography-electron capture detection was developed to determine twelve halogens-containing environmental hormones in vegetable and fruit samples. A wide linear range (0.07–100.0 ng g−1) with the determination coefficients in the range of 0.9907–0.9996 and low limits of detection (0.02–0.04 ng g−1, S/N = 3) were achieved under optimized experimental conditions. The applicability of the established method was evaluated by the determination of the environmental hormones from three different fruit samples (apple, nectarine and pear) and five vegetable samples (Chinese cabbage, pakchoi, baby cabbage, rape and round lettuce). The resulting relative recoveries ranged from 76.6% to 123% with the relative standard deviations less than 10%. This research demonstrates the application potential of the TCMP coated fiber in the analysis of the halogens-containing environmental hormones in real vegetable and fruit samples.