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

Trace 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.     

Occurrence of organochlorine pesticides and polychlorinated biphenyls in soils and sediments from Eastern Romania

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), such as DDT and analogues, hexachlorocyclohexane (HCH) isomers and hexachlorobenzene (HCB), were measured in surface soils and sediments from Eastern Romania. Thirty-nine soil samples from the forested zone, eight soil samples from a municipal waste-disposal site, and 10 sediment samples from the Bahlui River along the Iassy city were analysed using accelerated solvent extraction (ASE) and gas chromatography coupled to electron capture detection or mass spectrometry. The low mean concentrations of OCPs (11–31 and 22–84?ng?g^?1 for HCHs and DDTs, respectively) and PCBs (8–43?ng?g^?1) in soil samples from the forested zone suggest that contamination at most of these sites occurred predominantly through atmospheric transport from zones where these compounds were used and subsequently through atmospheric deposition. Contrarily, soil samples collected in the vicinity of a waste-disposal site near Iassy contained higher mean levels of PCBs (278?ng?g^?1, range 34–1132?ng?g^?1) than OCPs (6 and 101?ng?g^?1 of soil for HCHs and DDTs, respectively). The sediment samples collected along the Bahlui river throughout the Iassy city revealed higher mean levels of PCBs (59?ng?g^?1, range 24–158?ng?g^?1) compared with OCP levels (2 and 37?ng?g^?1 of soil for HCHs and DDTs, respectively). Furthermore, PCB profiles and concentrations in the sediment samples varied considerably along the river due to a wide variety of sources, such as different industries and waste sites. Although their sources are difficult to evaluate, the presence of POPs at most sites (especially at the waste-disposal site) may constitute a potential health hazard.     

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78?% to 121?%. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145?ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2?ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045?±?0.023?ng/g. Mean concentrations of PFOA were not significantly different (p?>?0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032?ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.     

An expeditious method for the determination of organochlorine pesticides residues in estuarine sediments using microwave assisted pre-extraction and automated headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry

Determination of organochlorine pesticides (OCPs) in sediments implicates extraction of these compounds from the matrix, which is difficult owing to strong interaction among OCPs and different constituents of the sediments, particularly organic content. The method here described is a combination of microwave assisted extraction (MAE), headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS), acting in selected-ion storage mode, or GC-electron capture detector (ECD, for routine analysis). Methanol was used as extracting solvent and aliquots of the MAE extracts (after inclusion of a step for sulfur elimination when required) were used to prepare aqueous solutions for HS-SPME. A complete automation of the SPME procedure increases the sample throughput, including standard addition for calibration purpose. The procedure has the advantage of exclude additional clean-up steps and pre-concentration before SPME. Application to reference sediments of different characteristics revealed absence of significant interferences from the matrix for alpha-lindane, gamma-lindane, aldrin, dieldrin, endrin, 4,4'-DDT, 4,4'-DDD, 4,4'-DDE, heptachlor, heptachlor epoxide and good sensitivity. Detection limits ranged from 0.005 to 0.11 ng of OCP per gram of dried sediment using GC-MS and from 0.01 to 0.26 ngg(-1) using GC-ECD. The linear response ranges embraced 5-6 orders of magnitude (up to 1000 ngg(-1)) in GC-MS, being narrower for GC-ECD. The method was successfully applied to sandy and muddy sediments from Portuguese rivers estuaries, enabling quantification of seven OCPs. The method resulted effective, relatively simple and fast, being suitable for routine monitoring of residues of OCPs from sediments of different grain size and organic matter content, which influence concentration, mobility and availability of contaminants.     

Multiresidue-matrix solid-phase dispersion method for determining 16 organochlorine pesticides and polychlorinated biphenyls in fish

Summary An effective, multiresidue-matrix, solid-phase dispersion — extraction (MSPD) and GC-MS method for the determination of 16 organochlorine pesticides (OCPs), as well as polychlorinated biphenyls (PCBs) from the level chlorination in fish is described. The method uses an octadecylsilyl-derivatized silica and Florisil-based MSPD co-column for direct, on-line clean-up. Recoveries calculated from five different fortification levels are >85% in all cases for OCPs, except for heptachlor and 4,4-DDT where recoveries of 78% and 81% are ob-tained, and >95% for PCBs. Detection limits determined for the OCPs vary from 19.6–91.1 ng g^–1, and from 71.4–111.2 ng g^–1 for the two to five chlorine-containing PCBs. The method has been applied to the analysis of fish grown in Er-Jen river (Taiwan) and method may serve as a screening protocol for the determination of OCPs and PCBs in fish.     

New method based on combining ultrasonic assisted miniaturized matrix solid-phase dispersion and homogeneous liquid-liquid extraction for the determination of some organochlorinated pesticides in fish

In this study, ultrasonic assisted miniaturized matrix solid-phase dispersion (US-MMSPD) combined with homogeneous liquid–liquid extraction (HLLE) has been developed as a new method for the extraction of organochlorinated pesticides (OCPs) in fish prior to gas chromatography with electron capture detector (GC-ECD). In the proposed method, OCPs (heptachlor, aldrin, DDE, DDD, lindane and endrin) were first extracted from fish sample into acetonitrile by US-MMSPD procedure, and the extract was then used as consolute solvent in HLLE process. Optimal condition for US-MMSPD step was as follows: volume of acetonitrile, 1.5 mL; temperature of ultrasound, 40 °C; time of ultrasound, 10 min. For HLLE step, optimal results were obtained at the following conditions: volume of chloroform, 35 μL; volume of aqueous phase, 1.5 mL; volume of double distilled water, 0.5 mL; time of centrifuge, 10 min. Under the optimum conditions, the enrichment factors for the studied compounds were obtained in the range of 185–240, and the overall recoveries were ranged from 39.1% to 81.5%. The limits of detection were 0.4–1.2 ng g⁻¹ and the relative standard deviations for 20 ng g⁻¹ of the OCPs, varied from 3.2% to 8% (n = 4). Finally, the proposed method has been successfully applied to the analysis of the OCPs in real fish sample, and satisfactory results were obtained.     

Biomonitoring and risk assessment of organochlorine pesticides among Saudi adults

The present study aimed to determine the serum organochlorine pesticides (OCPs) levels and risk of exposure among Saudi adults. Most OCPs are considered as endocrine-disrupting chemicals, and exposure can induce adverse health effects in both humans and wildlife. Serum OCP levels have not been documented in the Saudi population. Serum OCP concentrations were quantified using gas chromatography mass spectrometry (GC-MS/MS) in 302 serum samples collected from adult Saudis. All studied OCPs were detected in all participants. High concentrations of DDT and its metabolites (DDE and DDD) were detected in both males and females, with concentrations being significantly higher in males. High concentrations of 2,4-DDE, 4,4-DDE, and gamma-HCH were detected (18.31, 16.12, and 15.15 ng g⁻¹ lipid and 5.9, 7.1, and 8.6 ng g⁻¹ lipid for males and females, respectively). Alpha-HCH, Beta-HCH, 2,4-DDT, and 4,4-DDT were detected at concentrations lower than 2 ng g⁻¹. Levels of OCPs varied according to age and body mass index (BMI). Serum concentrations of OCPs significantly differed between Saudi males and females and were influenced by age and BMI. This study is the first to document serum OCP concentrations in Saudi adults from Riyadh, KSA. Monitoring programs are suggested for evaluating serum OCP concentrations in the general population to track toxicity levels and serve as an indicator of possible adverse health effects.     

Methods for selective determination of persistent organochlorine pesticide residues in water and sediments by capillary gas chromatography and electron-capture detection

Different extraction methods were evaluated for the determination of fifteen organochlorine pesticides (OCPs) in water and sediments. Liquid-liquid extraction (LLE) was evaluated for the pesticides analyses in water while Soxhlet extraction (SE) and microwave assisted extraction (MAE) methods were compared in sediment. Of all the extracting solvents used, dichloromethane gave the best results. Percentage recoveries ranged from 71.03 +/- 8.15 (dieldrin) to 101.25 +/- 2.17% [a-benzenehexachloride (alpha-BHC)] in water with LLE. In sediments the percentage recoveries with Soxhlet extraction method varied between 88.22 +/- 7.85 (endrin) and 109.63 +/- 5.10% (beta-BHC) and ranged from 74.11 +/- 9.82 (2,4 DDT) to 97.50 +/- 4.56% (alpha-BHC) with MAE. The limits of detection for the OCPs ranged from 5.5 to 20.6 ng/l and between 0.6 and 2.1 ng/g. respectively. The LLE and the SE methods were applied to water and sediments samples, respectively, from marine and freshwater sources in the Eastern Cape Province of South Africa that receive runoffs from agricultural lands and effluents from industries. The levels of OCPs ranged from 5.5 (2,4-DDD) to 450 +/- 0.10 ng/l (beta-BHC) in water samples and from 0.6 (aldrin and 2,4-DDD) to 184 +/- 0.12 ng/g (beta-BHC) in sediments for triplicate analyses. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulphan and the chlordanes were detected.     

Polycyclic aromatic hydrocarbons in citrus fruit irrigated with fresh water under arid conditions: Concentrations,sources, and risk assessment

In Jordan, as well as in all the world countries, consumption of citrus fruits is an essential part of the daily diet, so it is important to assess the potential risk of the persistent organic pollutants such as polyaromatic hydrocarbons (PAHs) in these fruits to the human health and identify their sources in order to eliminate or reduce them. This study reports 16 priority PAHs content in four types of peeled citrus fruits grown in Jordan valley. PAHs were detected in all the studied samples in variable quantities depending on the type of citrus fruits. The results showed that the highest PAH level corresponded to acenaphthene (35.018 µg/kg) in grapefruit. Among the carcinogenic PAHs, benzo[a]anthracene (BaA) and benzo(a)pyrene (BaP) were the most representative and found in all the analyzed fruit, soil, and water samples, whereas anthracene (ANT) was not detected at all. The mean ∑16 PAHs for the different fruits were found to be 62.593 µg kg^?1 in grapefruit, 24.840 µg kg^?1 in lemon, 22.901 µg kg^?1 in mandarin, and 5.082 µg kg^?1 in orange. The dominance of naphthalene (NAP) and acenaphthene (ACE) in soil under hot climatic conditions indicates the recent and continuous input of these types in the investigated area. The bioconcentration factor (BCF) for ∑16 PAHs was observed in the order of grapefruit > lemon > mandarin > orange. Based on the results of the principal component analysis (PCA), the primary sources of PAHs in agricultural soils mainly originated from biomass burning and vehicular emissions. The incremental lifetime cancer risk (ILCR) indicated that consumption of these four citrus fruits may expose human health to potential cancer risk. The findings of this study call the policymakers and public administrations to the formulation of stringent policies and actions to control biomass burning and vehicular emissions.     

Persistent organochlorines in human breast milk from Al-Sharkia Governorate,Egypt

In the present study, 23 human breast milk samples were collected in January 2009 from Fakous city, Al-Sharkia Governorate, Egypt. The samples were analysed for organochlorine pesticides such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, α, β, and γ-hexachlorocyclohexane (HCH) isomers. The average concentrations of ΣHCHs and ΣDDTs were 225 and 1315?ng?g^?1 lipid respectively. There was no significant difference between the levels of OCP and mother age, while there was a significant difference and correlation between the levels of OCP and the number of times the mother had breast fed (primiparae and multiparae) (p?<?0.05). The results suggested that DDT is still entering the environment depending on the observed ratio of DDE/DDT. The levels of OCP in human milk elucidated that we need to do more regular pollutant monitoring programs.     

Solid-phase microextraction for organochlorine pesticide residues analysis in Chinese herbal formulations

Solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used to determine pesticide residues in Chinese herbal formulations. Fibers coated with a 100-microm film thickness of poly(dimethylsiloxane) was used to extract 19 organochlorine pesticides (OCPs). The pesticides in the study consisted of alpha-, beta-, gamma-and delta-hexachlorocyclohexane, p,p'-DDD, p,p'-DDE, p,p'-DDT, o,p'-DDT, aldrin, dieldrin, endrin, endrin aldehyde, endrin ketone, endosulfan (I, II and sulfate), heptachlor, heptachlor epoxide, and methoxychlor. The optimal experimental procedures for the adsorption and desorption of pesticides were evaluated. The linearity was obtained with a precision below 11% RSD for the studied pesticides expect endosulfan sulfate (21%) in a wide range from 1 to 200 ng/g. Detection limits were reached at below ng/g levels. Heptachlor epoxide was determined at a calculated limit of 0.03 ng/g. Comparison between SPME and Soxhlet extraction showed that SPME has a less than one order detection limit for residue pesticide determination. The proposed method was tested by analyzing herbal formulations from a local market for OCP multiresidues. Some residues studied were detected in the analyzed samples. The results demonstrate the suitability of the SPME-GC-MS approach for the analysis of multi-residue OCPs in Chinese herbal formulations.     

Assessment of the occurrence and distribution of pharmaceuticals in a Mediterranean wetland (L'Albufera, Valencia, Spain) by LC-MS/MS

The distribution of 17 pharmaceuticals between water and the solid phase (sediments and soils) was studied by utilizing solid-phase extraction (SPE) and liquid chromatography?Ctandem mass spectrometry (LC-MS/MS). Two extraction procedures for soils and sediments, prior to the SPE, one based on pressurized liquid extraction (PLE) with hot water and the other on methanol/water ultrasonic extraction, were compared. Absolute recoveries were 71.2?C99.3% [relative standard deviation (RSD) <21.4%)] for water, and the method detection limits (MDLs) ranged from 0.3 to 10?ng?L^?1. Recoveries were 35.4?C105.3% (RSDs <19.1%) and 42.1?C97.8% (RSDs <14%) for soil and sediment samples, respectively, using PLE and 20.2?C86.5% (RSDs <25.1%) and 30.3?C97.4% (RSDs <19.1%) using ultrasonic extraction. Fifteen of the 17 pharmaceuticals were present in the L??Albufera water at concentrations up to 17???g?L^?1. Oxytetracycline and tetracycline were not detected. In sediments, only tetracycline, norfloxacin and diclofenac were not found. The other studied pharmaceuticals were present in the range from less than the method quantification limit (MQL) to 35.83?ng?g^?1. Among the 17 target compounds, ofloxacin, ciprofloxacin, norfloxacin, trimethoprim, clofibric acid and diclofenac were not detected in soil samples. The average concentrations ranged from less than the MQL for ibuprofen to 34.91?ng?g^?1 for tetracycline. These results indicate that pharmaceuticals could survive the wastewater treatment processes, which could lead to their dissemination in water environments.     

Application of QuEChERS method for extraction of selected persistent organic pollutants in fish tissue and analysis by gas chromatography mass spectrometry

The QuEChERS method developed for 22 organochlorine pesticides (OCPs) and 7-polychlorinated biphenyls (PCBs) in fish tissue involves a simple and efficient freezing technique for removal of lipids. The equipment developed consists of disposable syringes and a freezing block constructed from simple materials found in most laboratories. The freezing block keeps the temperature in the extract at -20.5°C up to 10 min after being exposed to room temperature. After the freezing step 69% of the lipids in tilapia and 61% in salmon are removed. Further reduction of co-extractives up to 96% in tilapia and 87% in salmon can be made by treatment with CaCl(2) and primary secondary amino sorbent (PSA) which removes the fatty acids. Spiking experiments in tilapia at 5 and 50 ng/g and extracted with acetonitrile show recovery range from 70 to 115% for all compounds. In salmon the recoveries are in the range 43-118% for the OCPs and 26-65% for the PCBs. Analysis of a standard reference material shows acceptable results for most of the pesticides but low results for the PCBs. The estimated LOQs were in the range 1-5 ng/g for tilapia and 2-10 ng/g for salmon. The method has been applied to analyse fish samples from Lake Koka in Ethiopia. It was investigated if addition of a less polar water miscible solvent than acetonitrile could increase the recovery of OCPs and PCBs. The results show that a mixture of 75% acetonitrile and 25% tetrahydrofurane (ACN/THF 75/25) clearly enhances the recoveries for most OCPs (47-101%) and PCBs (42-79%) from salmon. The recovery of aldrin increases significantly from 55% to over 80%. The method using ACN/THF 75/25 is applicable to the extraction of OCPs and PCBs from fish tissue having a lipid content of up to about 11% (salmon) with recoveries ≥70% for most of the OCPs and ≥42% for the PCBs.     

Organochlorine Pesticides in Water,Sediment and Fish from the Nile River and Manzala Lake in Egypt

Abstract

To assess the risks of organochlorine pesticides discharged into the hydrospheric environment of Egypt, river and lake water, drinking water, suspended solids, sediments and fish were collected during 1993—1994 from the Nile River and Manzala Lake in Egypt and were transported to Japan for chemical analysis. Among different organochlorine pesticides analyzed, p,p′-DDE was the most predominant in fish (7.6 to 67 ng/g wet wt.), sediments (3.2 to 432 ng/g dry wt.) and suspended solids (5.3 tc 138 pg/L). However, in the dissolved phase of water samples HCH compounds predominated (α-HCH, 71 to 2,815 pg/L). Concentrations of organochlorine pesticides, except chlordane, were higher in Manzala Lake than in the River Nile. Concentrations of organochlorine pesticides in fish corresponded with those in sediments from each location. Comparison of organochlorine concentrations in Nile River water with those reported in earlier studies suggested a decrease in concentrations during the last decade. However, concentrations of p,p′-DDE has increased in fish. It appears that the release of this metabolite from contaminated sediment is the major source of p,p′-DDE in fish during recent years.     

Elemental Analysis of Edible Mountain Nettle (Obetia tenax) and the Influence of Soil on Its Chemical Composition

In developing countries, the dietary intake of essential elements is largely dependent on the consumption of edible fruits and leafy vegetables. The distribution of elements in the indigenous edible plant, Obetia tenax (mountain nettle), was investigated as a function of soil quality from eight sites in KwaZulu-Natal, South Africa. The results show concentrations of elements in the leaves to be in decreasing order of Ca?>?Mg?>?Fe?>?Mn?>?Zn?>?Cr?>?Cu?>?Ni?>?Pb?>?Co?>?As?>?Cd?>?Se, and in the stems and roots to be in decreasing order of Ca?>?Mg?>?Fe?>?Mn?>?Zn?>?Cu?>?Ni?>?As?>?Pb?>?Co?>?Cd?>?Cr?>?Se. The quality and pollution status of soil was evaluated by geoaccumulation indices and enrichment factors, which indicated moderate cadmium contamination at the Msinga location that was confirmed by the pollution index and ecological risk levels of single-factor pollution. An assessment of overall contamination of soil using Nemerow pollution index showed moderate pollution by cadmium, while the potential toxicity index indicated low-grade risk for all elements at all sites. Principal component and cluster analysis revealed two groups of elements with similarities, As, Cd, Co, Cr, Cu, Mn, Ni, and Fe, suggesting a lithogenic source and an anthropogenic source for Pb and Zn. Correlation analysis showed significantly positive correlations between As, Co, Cr, Cu, Fe, and Ni/Cd in the soil, confirming the elements’ common origin.     

Occurrence of synthetic hormones in sewage effluents and Langat River and its tributaries,Malaysia

This study investigated for the first time the occurrence of selected synthetic hormones including 17α-ethinylestradiol, levonorgestrel, norethindrone and cyproterone acetate in Malaysian tropical waters. Samples were collected from the effluents of five sewage treatment plants (STPs) and at seven stations along the Langat River in Selangor, Malaysia, and its main tributaries. Samples were extracted by solid phase extraction (SPE) and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). In Langat river samples, only levonorgestrel and cyproterone acetate were found at 50% and 3.3% frequency. The concentrations detected for levonorgestrel ranged from less than the method detection limit (<MDL) to 213?ng?L^?1 and from?<?MDL to 76?ng?L^?1 for cyproterone acetate. For the STP effluent samples, levonorgestrel was <MDL in all samples and the concentrations detected were in the range?<?MDL – 262?ng?L^?1 for cyproterone acetate,?<?MDL ?11336?ng?L^?1 for norethindrone and?<?MDL – 1898?ng?L^?1 for 17α-ethinylestradiol.     

Metals in water and surface sediments from Henan reaches of the Yellow River, China

The concentrations of Cd, Cr, Cu, Ni, Pb and Zn were determined in the water and surface sediments from the Henan reaches of the Yellow River. Twenty-three sampling sites along the Yellow River and its tributaries were selected. Generally, metal concentrations were found to decrease in sequences of Zn > Cu > Pb > Cr > Ni > Cd in water and Zn > Cr > Pb > Ni > Cu > Cd in sediments. High levels of metal concentration were determined at a few stations of the river and its tributaries, such as Yiluo River, Si River and Qin River. The pollution of the Yellow River by Cd, Cr, Cu, Ni, Pb and Zn can be regarded as much higher compared to the background values, US EPA criteria (1999) and China water quality criteria (2002). For sediments, metal levels except Pb did not significantly exceed the average shale levels and backgrounds in several countries including China. Data analysis manifests that positive correlations were found between Cu, Ni and Zn in water, and Pb, Ni, Zn and Cr in sediments. The Pearson correlation coefficient analysis and Cluster analysis were provided to assess the possible contamination sources. The results indicate a general appearance of serious pollution along the banks of the Yellow River. The wastewaters discharged by the mine plants, smelter plants, power plants, battery plants, tannery plants, etc., and sewage inputs from the cities along the river banks may be the sources of metals.     

Adaptation and validation of QuEChERS method for the simultaneous analysis of priority and emerging pollutants in sediments by gas chromatography—mass spectrometry

A Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method has been adapted and validated for the simultaneous determination of priority (16 PAHs, 12 PCBs and 7 organochlorine pesticides (OCPs)) and emerging (carbamazepine, 9 musks and 6 sunscreens) pollutants in sediments by Gas Chromatography-Mass Spectrometry (GC-MS). The sample preparation was adapted by modifying the nature of the extraction solvent and optimising clean-up and evaporation steps. The method was validated by the analysis of spiked estuarine and marine sediments. Analytical performances were evaluated in terms of linearity, accuracy, precision and detection limits. The method shows good linearity (coefficients of determination > 0.998) and repeatability (RSD < 10%). Obtained recoveries are acceptable, ranging from 62% to 131% for all the compounds. Detection limits are estimated to range from 0.01 ng/g to 3.18 ng/g. This developed method offers the ability to detect and quantify several priority and emerging pollutants at low concentration levels in sediments.     

Ultrasonication followed by single-drop microextraction combined with GC/MS for rapid determination of organochlorine pesticides from fish

A novel, rapid and simple sample pretreatment technique termed ultrasonication followed by single-drop micro-extraction (U-SDME) has been developed and combined with GC/MS for the determination of organochlorine pesticides (OCPs) in fish. In the present work, the lengthy procedures generally used in the conventional methods like, Soxhlet extraction, supercritical fluid extraction, pressurized liquid extraction and microwave assisted solvent extraction for extraction of OCPs from fish tissues are minimized by the use of two simple extraction procedures. Firstly, OCPs from fish were extracted in organic solvent with ultrasonication and then subsequently preconcentrated by single-drop micro-extraction (SDME). Extraction parameters of ultrasonication and SDME were optimized in spiked sample solution in order to obtain efficient extraction of OCPs from fish tissues. The calibration curves for OCPs were found to be linear between 10-1000 ng/g with correlation of estimations in the range 0.990-0.994. The recoveries obtained in blank fish tissues were ranged from 82.1 to 95.3%. The LOD and RSD for determination of OCPs in fish were 0.5 ng/g and 9.4-10.0%, respectively. The proposed method was applied for the determination of bioconcentration factor in fish after exposure to different concentrations of OCPs in cultured water. The present method avoids the co-extraction of lipids, long extraction steps (>12 h) and large amount of organic solvent for the separation of OCPs. The main advantages of the present method are rapid, selective, sensitive and low cost for the determination of OCPs in fish.     

The development and optimization of a modified single-drop microextraction method for organochlorine pesticides determination by gas chromatography-tandem mass spectrometry

We have developed a new method for single-drop microextraction (SDME) for the preconcentration of organochlorine pesticides (OCP) from complex matrices. It is based on the use of a silicone ring at the tip of the syringe. A 5 μL drop of n-hexane is applied to an aqueous extract containing the OCP and found to be adequate to preconcentrate the OCPs prior to analysis by GC in combination with tandem mass spectrometry. Fourteen OCP were determined using this technique in combination with programmable temperature vaporization. It is shown to have many advantages over traditional split/splitless injection. The effects of kind of organic solvent, exposure time, agitation and organic drop volume were optimized. Relative recoveries range from 59 to 117 %, with repeatabilities of <15 % (coefficient of variation) were achieved. The limits of detection range from 0.002 to 0.150 μg kg^?1. The method was applied to the preconcentration of OCPs in fresh strawberry, strawberry jam, and soil.