Analysis Of Organochlorine Pesticides Research Articles

Development of deep eutectic solvent-based ultrasonic assisted liquid–liquid microextraction coupled with GC–MS; application in analysis of organochlorine pesticides from cheese samples

A deep eutectic solvent-based ultrasonic assisted liquid–liquid microextraction method was developed to extract organochlorine pesticides from cheese samples before their quantification with gas chromatography–mass spectrometry. A mixture of deionized water, potassium hydroxide solution, and thymol: decanoic acid deep eutectic solvent was used in the method development. Under the optimum method conditions, acceptable precision was achieved, with intra– and inter-day precisions falling within the ranges of 2.9–4.3 % and 3.5–4.7 %, respectively). A good coefficient of determination (r2 ≥ 0.993) was obtained over a wide concentration range (107–250,000 ng kg−1), with low limits of detection (32–58 ng kg−1) and quantification (107–193 ng kg−1). Additionally, acceptable extraction recoveries (57–79 %) were achieved. Method validation was conducted and the method was successfully applied to several cheese samples. Based on the results, all of the investigated samples were found to be free of investigated organochlorine residues.

Post-synthetic modification of covalent organic framework for efficient adsorption of organochlorine pesticides from cattle's milk

Analysis of organochlorine pesticides (OCPs) residues in milk faces a significant challenge. Herein, a sea urchin structured covalent organic framework bearing boric acid groups named COF-B(OH)2 was synthesized and applied as a coating material for solid-phase microextraction (SPME) of the OCPs in cattle’s milk. Its performance was superior to that of three commonly used commercial SPME fibers, which could be due to the coexistence of hydrogen bonding, halogen bonding, π-stacking and electrostatic interactions. Besides, the fiber coating displayed good stability and reusability. After optimization, a COF-B(OH)2 based SPME coupled with gas chromatography-electron capture detection was established for the sensitive detection of the OCPs from milk samples. The limits of detection (S/N = 3) were between 0.04 and 1.0 μg kg−1. Satisfactory accuracy was achieved with the method recoveries in the range of 87.5 % to 112.5 %. These results manifest the feasibility of the COF-B(OH)2 coated fiber for the enrichment of the trace OCPs from milk samples.

Analysis of Organochlorine Pesticides using Gas Chromatography and Mass Spectrophotometer show an elevated pollution rate in Albanian soils

Analysis of Organochlorine Pesticides using Gas Chromatography and Mass Spectrophotometer show an elevated pollution rate in Albanian soils

Compatibility of cloud point extraction with gas chromatography: Matrix effects of Triton X-100 on GC-MS and GC-MS/MS analysis of organochlorine and organophosphorus pesticides

Cloud point extraction is an environmentally benign and simple separation/concentration procedure that can be regarded as an alternative to classical liquid-liquid extraction. In the current work, it was studied the compatibility of cloud point extraction followed by back-extraction in low volume of organic solvent with gas chromatography-mass spectrometry (GC-MS and GC-MS/MS). Triton X-100 was preferred than Triton X-114 as a surfactant to produce the clouding phenomenon and hexane or isooctane was found to be appropriate organic solvents which can be used at the back-extraction step. It was observed that ca. 0.09 % w/w Triton X-100 was co-extracted in the organic phase (hexane or isooctane) so further study was carried out to find out its effect on the GC-MS (GC-MS/MS) measurement when liquid samples are injected without any pre-cleaning to remove the surfactant. The chromatographic separation and the mass detection were not deteriorated by the concomitant Triton X-100 for analysis of several Organochlorine and Organophosphorus pesticides (alpha-HCH, beta-HCH, gamma-HCH, Pentachlorobenzene, Hexachlorobenzene, Chlorpyrifos, Chlorpyrifos-methyl, Aldrin, Endrin, Dieldrin, alpha-Endosulfan, Heptachlor, Heptachlor-endo-epoxide-A, o,p-DDD, p,p-DDD, o,p-DDE, p,p-DDE, o,p-DDT and p,p-DDT). The stability of the GC system when introducing surfactant was assessed as acceptable (typically the peak area RSD% for 20 consecutive injections were below 5 %). Under the developed vaporization conditions using PTV or PSS injectors it can be deduced that Triton X-100 is deposited on the inner surface of the liner. This effect is beneficial since the resulting surfactant layer makes a surface which facilitates the pesticides transfer to the GC column. As a consequence, for some analytes, a substantial enhancement (up to 2.3 times) in the sensitivity was observed when the matrix-matched medium (0.09 % w/w Triton X-100 in organic solvent) is used compared to calibration in solely hexane or isooctane. Meanwhile, the measurement precision in the presence of Triton X-100 remains unchanged. The GC-MS/MS analysis was alternatively accomplished by the use of glass or metal liner and it was found that the glass one should be preferable. Finally, it can be concluded that cloud point extraction with Triton X-100 can be combined with GC-MS or GC-MS/MS analysis by applying liquid injection of the target analytes transferred in organic solvents such as hexane or isooctane. We have established a positive effect of Triton X-100 on the instrumental performance which is on opposite to the generally accepted concern of the negative influence of the surfactants on the gas chromatographic analysis.

Analysis of organochlorine pesticides in contaminated soil by GC-MS/MS using accelerated solvent extraction as a green sample preparation

ABSTRACT Organochlorine pesticides (OCPs), persistent organic pollutants, in the contaminated soil have been analysed by a gas chromatography-tandem mass spectrometry (MS) in this work. OCPs were extracted with a mixture of dichloromethane and n-hexane by using accelerated solvent extraction at elevated temperature and high pressure. The extractant was concentrated by a rotary vacuum evaporator and cleaned up by silica gel solid phase extraction. OCPs were then separated by a gas chromatography in combination with an electron impact ionisation MS in MS/MS mode. The limit of detection, limit of quantification and other important parameters of the GC-EI-MS/MS analytical method, such as repeatability, recovery and so on, have been investigated and presented. Limit of detection and limit of quantification have been achieved from 0.005 ng g−1 (p,p’-DDE) to 0.405 ng g−1 (dieldrin) and 0.016 ng g−1 to 1.216 ng g−1, respectively. The repeatability of this method was achieved below 8.3% and 13.7% for short- and long-term stability. Recovery of all OCPs ranged from 78.1% ± 1.5% to 117.5% ± 3.2%. The developed analytical method was validated by spiking experiments in the real samples. The validated method has been then used for the analysis of OCPs in the soil samples that were collected from the contaminated areas in Vietnam. Results showed the presence of hexachlorocyclohexane isomers and p-p’-DDT in all analysed samples at elevated levels.

Multi residue analysis of persistent organochlorine pesticides in fish from Baro River, Gambella, Southwest Ethiopia

In this study, the concentrations of organochlorine pesticides in thirty (30) randomly collected Tilapia Zilli fish samples from the Baro River, Ethiopia were determined. The pesticide residues were extracted by soxhlet extraction technique using a mixture of n-hexane and acetone. The extracts were cleaned with silica gel and analyzed using a GC-MS. Concentrations of organochlorine pesticides were calculated from linear calibration curves of nine mixtures of standards with a concentration range of 5-200 μg/kg in the fish sample and had correlation coefficients of 0.999 for all concentrations. The ranges of the limit of detections (LODs) and limit of quantifications ( LOQs) were 0.008–0.017 μg/kg and 0.025–0.052 μg/kg respectively. Recovery was determined from spiked samples at concentrations of 5 μg/kg, 60 μg/kg, and 200 μg/kg. Recoveries of 90.87–102.6% were obtained and the method precision calculated from relative standard deviation (RSD) was found to be 1.00–8.62%. Of the thirteen studied organochlorine pesticides five of them were detected in collected fish samples with concentrations of 67.08 μg/kg, 15.35 μg/kg, 16.6 μg/kg, 3.87 μg/kg, and 17.1 μg/kg for Endosulfan II, Endrin, Endosulfan I, 4,4’-DDD, and Chlordane, respectively. The occurrence of organochlorine pesticide residues in fish samples shows that these compounds have been used in the study areas. The levels of chlordane and Endosulfan II detected in fish samples were above the maximum residual limits (MRLs) set by the Codex Alimentarius Commission. Therefore public awareness of pesticide use and management needs to be worked on by concerned bodies.

Effervescence-assisted dispersive liquid-liquid microextraction for extraction and preconcentration of organochlorine pesticides in water samples

ABSTRACT. In this paper, effervescence-assisted dispersive liquid-liquid microextraction method has been developed for the extraction and preconcentration of organochlorine pesticides in water samples before their determination by gas chromatography-mass spectrometry. The method involves in-situ generation of CO2 bubbles to induce dispersion of the extraction solvent in the aqueous sample. Different parameters affecting the extraction efficiency of the method including the type and concentration of the effervescent agents as well as the type and volume of extraction solvent were optimized. Under optimum conditions, matrix matched calibration curves were constructed at eight concentrations ranging from 0.6–4.0 ng/mL showed good linearity with coefficient of determinations of ≥ 0.9961. The limits of detections and quantifications ranged from 0.2–0.4 and 0.6–1.0 ng/mL, respectively. The intra- and inter-day precisions studied at two concentration levels had below 5% relative standard deviation values. Similarly, recoveries investigated at two concentration levels ranged from 80.7–117.4%. The findings demonstrated that proposed method is simple, rapid, and efficient to be used as alternative method for analysis of organochlorine pesticides from environmental water and other similar matrices.
 
 KEY WORDS: Effervescence agents, CO2 bubbles, Organochlorine pesticides, Water samples, gas chromatography-mass spectroscopy
 
 Bull. Chem. Soc. Ethiop. 2023, 37(5), 1109-1122. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i5.4

Target and non-target analysis of organochlorine pesticides and their transformation products in an agrochemical-contaminated area

Organochlorine pesticides show biological toxicity and their degradation typically takes many years. Previous studies of agrochemical-contaminated areas have mainly focused on limited target compounds, and emerging pollutants in soil have been overlooked. In this study, we collected soil samples from an abandoned agrochemical-contaminated area. Target analysis and non-target suspect screening by gas chromatography coupled with time-of-flight mass spectrometry were combined for qualitative and quantitative analysis of organochlorine pollutants. Target analysis showed that dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) were the main pollutants. With concentrations between 3.96 × 106 and 1.38 × 107 ng/g, these compounds posed significant health risks at the contaminated site. Non-target suspect screening identified 126 organochlorine compounds, most of which were chlorinated hydrocarbons and 90% of the compounds contained a benzene ring structure. The possible transformation pathways of DDT were inferred from proven pathways and the compounds identified by non-target suspect screening that had similar structures to DDT. This study will be useful for studies of the degradation mechanism of DDT. Semi-quantitative and hierarchical cluster analysis of compounds in soil showed that the distribution of contaminants in soil was influenced by the types of pollution sources and distance to them. Twenty-two contaminants were found in the soil at relatively high concentrations. The toxicities of 17 of these compounds are currently not known. These results improve our understanding of the environmental behavior of organochlorine contaminants in soil and are useful for further risk assessments of agrochemical-contaminated areas.

Analysis of Organochlorine Pesticides in a Soil Sample by a Modified QuEChERS Approach Using Ammonium Formate

Currently, the QuEChERS method represents the most widely used sample preparation protocol worldwide for analyzing pesticide residues in a broad variety of matrices both in official and non-official laboratories. The QuEChERS method using ammonium formate has previously proven to be advantageous compared to the original and the two official versions. On the one hand, the simple addition of 0.5 g of ammonium formate per gram of sample is sufficient to induce phase separation and achieve good analytical performance. On the other hand, ammonium formate reduces the need for maintenance in routine analyses. Here, a modified QuEChERS method using ammonium formate was applied for the simultaneous analysis of organochlorine pesticide (OCP) residues in agricultural soil. Specifically, 10 g of the sample was hydrated with 10 mL of water and then extracted with 10 mL of acetonitrile. Next, phase separation was carried out using 5 g of ammonium formate. After centrifugation, the supernatant was subjected to a dispersive solid-phase extraction clean-up step with anhydrous magnesium sulfate, primary-secondary amine, and octadecylsilane. Gas chromatography-mass spectrometry was used as the analytical technique. The QuEChERS method using ammonium formate is demonstrated as a successful alternative for extracting OCP residues from a soil sample.

Effervescent powder-assisted floating organic solvent-based dispersive liquid-liquid microextraction for determination of organochlorine pesticides in water by GC–MS

An effervescent powder-assisted floating organic solvent-based dispersive liquid-liquid microextraction was introduced for determination of 13 organochlorine pesticides in water samples. In this method, a less toxic low-density organic solvent was used as extraction solvent. The extraction solvent was dispersed in to the aqueous sample via CO2 bubbles, in-situ generated up on addition of water to a falcon tube containing the mixture of effervescent powder precursors as well as the extraction solvent. Various experimental parameters such as effervescent and its weight fractions, extraction solvent type and its volume, the total mass of effervescent precursors, and the effect of salt were investigated and the optimal conditions were established. Under the optimum conditions, the proposed method exhibited good linearity for all target pesticides with the coefficient of determinations varying from 0.9981 to 0.9997. The limits of detection and quantification were within the range of 0.03–0.24 and 0.26–0.75 μg/L, respectively. The intra- and inter-day precisions which were expressed in terms of the relative standard deviation ranged from 0.33 to 4.47 and 0.51–5.52%, respectively. The enrichment factors and recoveries ranged from 24 to 293 and 76–116%, respectively. The proposed method could be used simple, cheap, fast, and environmentally friendly alternative for analysis of organochlorine pesticides from environmental water and other similar matrices.

Distribution characteristics, source analysis and risk assessment of organochlorine pesticides in Ny-Ålesund, Arctic

The distribution characteristics, sources, and risk levels of organochlorine pesticides (OCPs) in Ny-Ålesund of the Arctic region during China's 10th Arctic expedition were studied in this paper. Results showed that the concentration of OCPs in the surface soil of the Ny-Ålesund region ranged from 0.59 ng·g−1 to 3.87 ng·g−1, with an average concentration of 2.22 ng·g−1. Source analysis showed that the OCPs in the study area mainly originated from historical residues, and a certain degree of conversion between congeners of hexachlorocyclohexanes and dichlorodiphenyltrichloroethanes in the soil occurred due to environmental factors. Ecological risk assessment indicated that the study area was at a low ecological risk level, but the potential environmental impact of OCPs could not be neglected due to the specificity and sensitivity of the Arctic environment.

Determination of Organochlorine Pesticide Residues and Trace Metal Concentration in Well and Stream Waters from Agricultural Farm Settlement in Ile-Oluji, Ondo State

Pollutants is constantly introduced into the aquatic environment primarily due to amplified industrial activity, technical development, growing human population and mistreatment of natural resources, agriculture and domestic wastes run-off. Among these pollutants, Organochlorine Pesticides and some trace metals such as Lead (Pb)Mercury(Hg)and Cadmium (Cd) are found as one of the most hazardous because of their toxicity to organisms This study investigate the levels of organochlorine pesticide (OCP) residues and Trace Metal concentration in Well and Stream waters from Agricultural Farm Settlement in Ile-Oluji Ondo State. Ten (10) samples each of 1 Liter Well and Stream waters were collected randomly for trace metal analysis and another Ten (10) samples each of 2.5 Liter Well and Stream waters were collected for Organochlorine Pesticide analysis within the Farm Settlement and its vicinity. Quantitative determination of the OCPs was determined using Gas Chromatography-Mass Spectrometer after liquid-liquid extraction with (v/v) ethyl acetate/dichloromethane mixture and the Trace Metal was determined using Atomic Absorption Spectrophotometer. The results show that organochlorine pesticide residues were not detected in all the well water samples except for AKN where Heptachlor was detected in the concentration of 0.11 mg/L while all samples from the stream were contaminated with the Organochrorine pesticides at appreciably higher concentration than WHO standards. The results also shows that all the trace metals analyzed for are present except for some well samples where Lead concentration is below the detection limit. The mean concentration of some of the sampling sites were below the permissible limit for WHO while some are higher than the permissible limit.

Application of the NU-1000 coated SPME fiber on analysis of trace organochlorine pesticides in water

Herein, a novel solid-phase microextraction (SPME) fiber based on the NU-1000 sorbent was developed for direct immersion extraction of organochlorine pesticides (OCPs) in water samples. As a kind of metal-organic framework, the NU-1000 possessed the mesoporous channels which were beneficial for the mass transfer of target analytes. Extraction equilibrium was achieved rapidly with the optimal extraction time of 30 min. The NU-1000 coated fiber with a high specific surface area showed better extraction efficiencies than commercial fibers (65 μm PDMS/DVB or 85 μm PA) towards OCPs, with the enrichment factors of the NU-1000 coated fiber 2–20 times higher than the latter. NU-1000 coated fiber showed higher extraction efficiencies toward polycyclic aromatic hydrocarbons (PAHs) than OCPs and nitrobenzenes. This indicated that π-π interaction and CH-π interaction between pollutants and aromatic groups of the NU-1000 contributed to the high extraction efficiencies. Under the optimal conditions (extraction at 40 °C for 30 min and desorption at 260 °C for 6 min), the NU-1000 coated fiber coupled with gas chromatography-mass spectrometry (GC-MS) exhibited satisfied analytical performance on analysis of OCPs, with a wide linear range (0.1–2000 ng L−1), low limits of detections (LODs, 0.011–0.058 ng L−1), and good reproducibility and repeatability. The established method has been successfully applied to the determination of OCPs in surface water with good sensitivity and recoveries, which proved the great promise of the NU-1000 on the extraction of organic pollutants with conjugated groups.

Multi residue analysis of organochlorine pesticides in fish, milk, egg and their feed by GC-MS/MS and their impact assessment on consumers health in Bangladesh

The present study determined the concentration of organochlorine pesticides (OCPs) in fish feed, cattle feed, poultry feed, fish, Poultry chicken meat, egg, Cow milk and beef and assessed the potential human health risks due to consumption of foods from animal sources. Gas Chromatography coupled with Mass Spectrometry (GC–MS/MS) was used to detect the presence of OCPs residues. Several OCPs residues including Aldrin, p’,p’-DDD, p’,p’-DDT and Endosulfan sulfate were detected in fish; Aldrin, p’,p’-DDE, Heptachlor, p’,p’-DDT and HCH were detected in poultry chicken meat; Aldrin, p’,p’-DDE and DDD were detected in egg; Aldrin, p’,p'DDE and p’,p’-DDT were detected in cow milk and Aldrin, p’,p’-DDE, p’,p’-DDT, Endrin and HCH were detected in beef. OCPs residues were detected within the range of EU/FAO's recommended maximum residue limits (MRLs). The Health risk index (HI) values of detected OCPs were ranged from 0.295914 to 0.834996; 0.00059628 to 0.09085834; 0.087882 to 0.090889; 0.05462 to 0.312114 and 0.008468 to 0.179828 for fish, Poultry chicken meat, egg, cow milk and beef respectively. The HI values of simultaneous exposure to different OCPs from the total food of animal origin (cow milk, beef, fish, chicken meat and egg) were 0.829889954, 0.825673025, 0.035987457, 0.0557969 and 0.179828343 for aldrin, Σ p,p-DDE, DDD and DDT, Heptachlor, HCH and Endrin respectively which are also below than 1. HI value of lower than 1 indicates no potential health risks while more than 1 HI value indicates potential health hazardous. This work provided information about the occurrence of OCPs traces in animal feed and animal derived food items and their impact on public health.

Assessment and chemical analysis of macro elements, heavy metals, proximate compositions and pesticides contamination on rice cultivated from Kura LGA, Kano, Nigeria

Six rice brands BG-213, Notore, Das, Kwandala, Jeep and Jamila brands were collected from various locations in Kura local government area of Kano, Nigeria. Rice brands were analyzed for proximate compositions, macro elements, heavy metals and pesticides using standard analytical techniques. Results of proximate compositions analyses indicate that the average mean value of moisture content, crude protein, crude fat, ash content and crude fiber in rice brands were; 10.27, 9.17 3.82, 1.93 and 0.34 % respectively. The average mean concentrations of macro elements (Calcium (Ca) and Magnesium (Mg)) are; 53.5 mg/kg and 46 mg/kg, while mean levels of Heavy Metals: Zinc (Zn), Copper (Cu), Nickel (Ni), Chromium (Cr), Cadmium (Cd) and lead (Pb) were; 11.87, 4.04, 0.06, 0.00, 0.044 and 0.00 mg/kg respectively. Pearson Correlation Coefficient analysis performed on rice brands using MATLAB student version VI software shows results of macro elements and heavy metals were at a significant level of p≥0.05. The GC/MS analysis of organochlorine pesticides in rice brands revealed that the level of pesticides was below the detection limit (BDL) this indicates that brands of rice obtained from the Kura local government area were safe and free from heavy metals and pesticides contamination could be attributed to restriction or regulation for compliance on the application and economy because most of these pesticides are very costly.

Needle-trap device packed with the MIL-100(Fe) metal–organic framework for the extraction of the airborne organochlorine pesticides

This study was presented the development of the needle trap device (NTD) packed with the MIL-100(Fe) metal–organic framework (MOF) for extraction of organochlorine pesticides (Hexachlorobenzene, Aldrin, Alpha-Chlordane, Dildrin and DDT isomers) from the air environment for the first time. Specifications of synthesized MIL-100(Fe) were identified by Fourier-transfer infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS) and elemental mapping techniques. The optimization of sampling and desorption parameters such as humidity, time, and temperature were performed by response surface methodology (RSM). Sampling and analysis of organochlorine pesticides were accomplished under different conditions in the laboratory scale and then was employed in the field study for the real air samples. The highest response was obtained at desorption temperature of 280 °C and desorption time of 5 min. The temperature and humidity of the sampling site were set to 30 °C and 25%. Furthermore, the Limit of Detection (LOD) and Limit of Quantification (LOQ) for the targeted analytes were determined in the range of 0.04–0.41 µg/m3 and 0.21–1.82 µg/m3, respectively. Moreover, from the recovery standpoint, any significant change was not detected on the analytes after 6 days of storage at 4 °C. Also, the results of this study showed a high correlation (R2 = 0.9882) between the results of the proposed method with the standard NIOSH method. This study exhibited that the proposed MIL-100(Fe)@NTD method can be employed as an eco-friendly, reliable, sensitive, and efficient procedure for sampling and determination of the organochlorine pesticides compared to the standard NIOSH method.

Analysis of persistent organochlorine pesticides in shellfish and their risk assessment from aquafarms in Taiwan

In Taiwan, freshwater clams (Corbicula fluminea) and hard clams (Meretrix lusoria) are the most frequently raised shellfish in land-based pond aquaculture, but research on the accumulation of organochlorine pesticides (OCPs) in these shellfish is limited. We detected the levels of 14 OCPs in 62 shellfish from Taiwanese aquafarms by performing gas chromatography–tandem mass spectrometry. OCP residues were detected in 4.84% of the samples including readings of 0.04 mg/kg chlordane (in a freshwater clam), 0.03 mg/g p,p′-DDE (in a freshwater clam), and 0.02 mg/g p,p′-DDE (in a hard clam). However, the associated estimated daily intake values were less than the acceptable daily intake levels of chlordane and p,p′-DDE Therefore, the consumption of these shellfish presents no immediate health risks. Our findings contribute to food safety and serve as a reference for OCP screenings for aquatic shellfish.

Magnetic Solid-Phase Extraction Based on Amino-functionalized Magnetic Starch for Analysis of Organochlorine Pesticides.

A magnetic starch modified with 3,5-diaminobenzoic acid and 3-aminopropyltriethoxysilane (Fe-starch@DABA-APTES) was synthesized and applied as adsorbent for the extraction of organochlorine pesticides (OCPs). Magnetic solid-phase extraction was developed using 75 mg of the sorbent and 15 mL of a sample solution. Extraction was conducted on a vortex mixer for 40 s. The adsorbent was collected using an external magnet before eluting the analytes using 0.5 mL of methanol. Quantification of the analytes was performed using gas chromatography with a micro-electron capture detector. The linearity was obtained for the studied OCPs in the range between 0.01 - 2.00 μg L-1. The detection and quantification limits were obtained in ranges of 0.5 - 4.0 and 1.5 - 15.0 ng L-1, respectively, with enrichment factors of up to 39. The precision in terms of the intra- and inter-day relative standard deviations (RSDs) were below 4.75, and 9.25%, respectively. The developed method has been applied in natural water and agricultural product samples. The recoveries ranged between 59.83 - 132.67% (RSDs < 10.73%).

Dynamic microwave-assisted extraction combined with liquid phase microextraction based on the solidification of a floating drop for the analysis of organochlorine pesticides in grains followed by GC

A convenient, cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides in grains including rice, maize and millet. Twelve samples can be processed simultaneously in the method. During the extraction process, 10% acetonitrile-water solutions containing 110μL of n-hexadecane were used to extract organochlorine pesticides. Subsequently, 1.0g sodium chloride was placed in the extract, and then centrifuged and cooled. The n-hexadecane drops containing the analytes were solidified and transferred for determination by gas chromatography-electron capture detector without any further filtration or cleaning process. Limits of detection for organochlorine pesticides were 0.97–1.01μg/kg and the RSDs were in the range of 2.6%–8.5%. The developed technology has succeeded in analyzing six real grains samples and the recoveries of the organochlorine pesticides were 72.2%–94.3%. Compared with the published extraction methods, the developed method was used to analyze organochlorine pesticides in grains, being more environmentally friendly, which is suitable for the daily determination of organochlorine pesticides.

Variation analysis of organochlorine pesticides in waters and sediments from a tropical river

In this paper, it is analyzed the temporal variation of organochlorine pesticides (OCPs) in water and sediments from a river influenced by the activity in an agricultural field in a tropical country during the period 2013-2016. The novelty consists of increasing the studies of concentrations of OCPs in water and sediments of rivers for contributing to establish thresholds of concentrations that allow to protect the biota in soils and waters. The mean values of the OCPs dissolved in water and sorbed on sediments varied as follows: p.p'-DDT (0.001 – 0.022 μg.L-1), (0.1 – 8.24 μg.kg-1), o.p'-DDT (0.001-0.021 μg.L-1), (0.51 – 5.76 μg.kg-1), p.p'-DDD (0.001-0.01 μg.L-1), (0.14 – 1.96 μg.kg-1), p.p'-DDE (0.001-0.027 μg.L-1), (0.52 – 7.32 μg.kg-1), o.p'-DDE (0.001-0.041 μg.L-1), (0.2 – 5.52 μg.kg-1), Aldrin (0.004-0.053 μg.L-1), (0.23 – 8.22 μg.kg-1), Dieldrin (0.001-0.032 μg.L-1), (1.13 – 6.82 μg.kg-1) and Endrin (0.001-0.008 μg.L-1), (1.16 – 7.60 μg.kg-1). The management of OCPs by the activity in the agricultural field is being controlled.