Matrix Solid-Phase Dispersion Combined with GC–MS/MS for the Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Marketed Seafood

An analysis method based on matrix solid-phase dispersion (MSPD) and gas chromatography tandem mass spectrometry was developed and applied for the analysis for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the marketed seafood such as fish, shrimp and shellfish. The parameters of the method including the type and amount of the absorbent, as well as the type and volume of the elution solution were optimized. The recoveries were between 70 and 120% with RSDs less than 20%, and the LODs and LOQs were 0.011–0.046 and 0.037–0.153 ng g^?1 under optimized conditions. The results showed that most of the OCPs and PCBs were detectable in the marketed samples with the average concentration range of 0.722–14.206 and 0.034–1.184 ng g^?1, respectively. Among the 21 OCPs detected, DDTs had a relatively higher concentration level. And in the PCBs, the concentration of PCB28 was over 45% of the total PCBs determined in all the samples. The developed method was simple, fast and effective, and could successfully be applied for trace amount of OCPs and PCBs determination in seafood matrixes.     

A Novel Fiber with Phenyl-Functionalized MSU (Michigan State University) Coating for Solid-Phase Microextraction Combined with High Performance Liquid Chromatography for Preconcentration and Determination of Trace Polychlorinated Biphenyls in Environmental Water Samples

A novel and robust phenyl-functionalized MSU-1 (Ph-MSU) coated fiber for solid-phase microextraction (SPME) coupled to high performance liquid chromatography (HPLC) was developed for the preconcentration and the determination of 2,4,4′-trichlorobiphenyl (PCB 28), 2,4′,5-trichlorobiphenyl (PCB 31), 2,2′,5,5′-tetrachlorobiphenyl (PCB 52), 2,2′,4,5,5′-pentachlorobiphenyl (PCB 101), 2,3′,4,4′,5-pentachlorobiphenyl (PCB 118), 2,2′,3,4,4′,5′-hexachlorobiphenyl (PCB 138), 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153), and 2,2′,3,4,4′,5,5′-heptachlorobiphenyl (PCB 180) in environmental water samples. Experimental conditions affecting SPME were examined in detail. The Ph-MSU coating provided large porosity and short-range mesostructures necessary for high extraction capacity and rapid mass transfer of PCBs. The Ph-MSU coated fiber exhibited selectivity for PCB 28, PCB 31, PCB 118, and PCB 138 in a limited extraction time. Good linearity for all PCBs was obtained with correlation coefficients from 0.9987 to 0.9994. The recoveries were within 94.3% to 103% for the spiked water with 300 ng · L^?1 per PCB. The relative standard deviations (RSDs) ranged from 3.10% to 6.23% and the limits of detection (LODs) were between 8.73 ng · L^?1 and 13.8 ng · L^?1. The proposed method was applied for the determination of PCBs in real river water and rainwater samples. The median recoveries ranged from 85.6% to 118% with RSDs between 4.23% and 8.78%. The experimental results demonstrated that the Ph-MSU fiber coating could be reused for over 250 times without loss of the extraction efficiency. These results clearly indicate that the Ph-MSU coated fiber was rapid, sensitive, and suitable for the preconcentration and determination of trace PCBs in environmental water samples.     

Level of Polychlorinated Biphenyls in Marine Environment of Algiers Bay,Algeria

Polychlorinated Biphenyls (PCBs) are persistent organic pollutants with significant bioaccumulation in the global environment. Owing to their high toxicity and lipophilic property, PCBs are potential threat to the human and ecological system.

The objective of this work was to investigate the polychlorinated biphenyls in seawater and blue mussels Mytilus galloprovincialis collected in the eastern coastal side of the Algiers bay. Surface and bottom water samples were collected at six different periods from July to October 2002 in the port of Tamentfoust and four locations around the port. Mussel samples were collected from Tamentfoust port and Surcouf beach. After extraction, the PCBs levels were determined in marine water and biological samples by gas chromatography with electron capture detector. Total polychlorinated biphenyls concentrations varied from 4.0 to 18.8 ng · L^?1 in surface and from 4.4 to 16.6 ng · L^?1 in bottom seawater and were relatively high in August (30th and 45th days).

In mussels that concentrate the organochlorinated compounds in their tissues, the sum of ICES 7 PCBs concentrations was relatively high. It ranged from 64.2 to 185.8 ng · g^?1 dw (average 125.8 ng · g^?1 dw) in samples collected from Surcouf. The level of contamination in Tamentfoust port mussels was about twice higher (225.2 ng · g^?1 dw).

The observed PCBs distribution was close to that of common commercial mixture and suggests an industrial origin of this pollution emitted from a continental source in addition to the port activities. Although the use of target compounds has been banned for more than three decades, they are still persistent in Algiers Bay.     

A Screening Method for Polycyclic Aromatic Hydrocarbons Determination in Sediments by Headspace SPME with GC–FID

A screening method for polycyclic aromatic hydrocarbons (PAHs) determination in sediment using headspace solid phase microextraction (HS-SPME) with gas chromatography–flame ionization detection was developed. In order to obtain the convenient experimental conditions for HS-SPME extraction an experimental design with two steps was done. 0.2 g of sediment and 85 µm polyacrylate fibre, 80 °C and 120 min were the chosen extractions conditions. The limit of detection (LOD) was from 0.8 ng g⁻¹ (fluoranthene) to 8 ng g⁻¹ (chrysene). The relative standard deviation (RSD) was less than 7.0%. Determination of PAHs in NRC–CNRC–HS–3B reference marine sediment showed good agreement with the certified values. The method was applied in the analysis of ten river and estuary surface sediments from Gipuzkoa (North Spain). PAHs total concentration ranged from 400 to 5,500 ng g⁻¹.

     

Determination of Atmospheric Polycyclic Aromatic Hydrocarbons Using Accelerated Solvent Extraction

Abstract

An accelerated solvent extraction (ASE) method has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) present in both atmospheric particulate and gaseous phases in this study. Extraction parameters such as the combination of solvents, extraction temperature, and static extraction time were investigated and optimized. Effective extraction was achieved using a 3:1 mixture of n-hexane and acetone as extraction solvents at 100°C in 30 min for all the compounds studied. The optimized extraction method was compared with conventional extraction methods and validated using National Institute of Standards and Technology (NIST)–certified standard reference material (SRM) 1649a. The recoveries obtained for certified 12 PAHs were in the range of 82–126% with relative standard deviation (RSD) between 6 and 28%. The validated ASE technique was used followed by gas chromatography–mass spectrometry (GC-MS) for the determination of PAHs distributed between gaseous and particulate phases in the atmosphere of Singapore. Total average concentrations of PAHs in air samples were 33.54 ± 19.32 ng m^?3, with 4.72 ± 2.80 ng m^?3 in particulate phase and 28.82 ± 16.92 ng m^?3 in gaseous phase, respectively. The results obtained from this study are compared to those reported from other areas of the world.     

Development of Immunoaffinity Sample-Purification for GC–MS Analysis of Ractopamine in Swine Tissue

A method combining immunoaffinity chromatography with gas chromatography–mass spectrometry (GC–MS) has been established for determination of ractopamine residues in swine liver and urine. After clean-up on an immunoaffinity chromatography column, GC–MS analysis revealed recovery from blank swine liver and urine fortified at 2.5–20 ng g^?1 (ng mL^?1 for urine), respectively, was 68.2–78.6 and 76.2–83.1%. The limits of detection and quantification were 0.5 ng g^?1 (or ng mL^?1) and 2.0 ng g^?1 (or ng mL^?1), respectively. The procedure was used for analysis of ractopamine residues in samples of swine liver and urine in which the levels were unknown. The amounts detected were 9–216 ng g^?1 (ng mL^?1).     

Sensitive GC/MS determination of 15 isomers of chlorobenzoic acids in accelerated solvent extracts of soils historically contaminated with PCBs and validation of the entire method

Chlorobenzoic acids (CBAs) are the major metabolite of aerobic bacterial degradation of polychlorinated biphenyls (PCBs). A rapid and simple simultaneous derivatisation method has been developed for gas chromatography-mass spectrometry determination in historically PCB-contaminated soils for 15 isomers of mono-, di-, tri-, tetra-, and pentachlorobenzoic acids in CBA mixtures. Two derivatisation agents (diazomethane and methyl chloroformate) and various conditions were evaluated (temperature, time, solvents, catalysts) in terms of efficiency. The optimised derivatisation method with diazomethane and 1% methanol running 1 hour at 5°C was used for derivatisation of extracts of soils and river sediment from historically PCB-contaminated sites; the extracts were prepared using accelerated solvent extraction by a previously described method. Methylated CBAs were separated by gas chromatography using a system with two different common columns, DB-5 and DB-200, in series-coupled (tandem) arrangement and detected by EI-MS. A clean-up with a gel permeation chromatography was carried out to remove soil interfering matrix compounds as well as major portion of PCBs. The limits of quantification ranged between 1 and 10 ng g^?1 of individual CBA in the soil. The procedure was applied to various soil samples from Lhenice (Czech Republic) highly contaminated with PCBs. CBAs were found in all tested soils and also in the river sediment. The most contaminated soil contained all CBAs representatives under the study with a total concentration of 3.1 µg g^?1 of dry soil.     

Pressurised fluid extraction of polycyclic aromatic hydrocarbons and their polar oxidation products from atmospheric particles

An effective method utilising pressurised fluid extraction (PFE) to simultaneously extract polycyclic aromatic hydrocarbons (PAHs) and their polar oxidation products from atmospheric particulate matter (PM) is presented. The PFE method is advantageous over the traditional Soxhlet extraction due to its lower solvent consumption (9 mL compared to 90 mL) and shorter extraction time (15 min versus 18 h). Seventy compounds including PAHs and polar PAH oxidation products containing carbonyl (oxy-PAHs), hydroxyl (hydroxy-PAHs), and carboxylic acid (carboxy-PAHs) groups were targeted in the extraction of two different PM matrices: wood smoke (WS) and diesel exhaust (DE) PM. The PFE method was optimised and then compared to Soxhlet extraction for both PM matrices. The overall amounts of PAHs and their derivatives extracted from WS PM were slightly higher for the optimised PFE method (1849 ± 21 and 1863 ± 25 µg g^?1 with dichloromethane (DCM) and methanol (MeOH), respectively) than those obtained with Soxhlet extraction (1726 ± 33 and 1769 ± 22 µg g^?1 with DCM and MeOH, respectively). For DE PM (standard reference material (SRM) 2975) the overall amounts extracted by both methods were similar (average of 165 ± 6 µg g^?1), agreeing with previously published values. The detailed evaluation of extraction efficiencies for WS PM showed similar amounts for unfunctionalised PAHs (1100 µg g^?1) for both methods and solvents. For DE PM the mass yields for PAHs using PFE with DCM (62 ± 1 µg g^?1) were the highest and nearly 20% higher than those obtained with MeOH (53 ± 2 µg g^?1). The total mass yields of carboxy and hydroxy-PAHs from WS PM were also similar (412 ± 18 and 407 ± 11 µg g^?1) for PFE and Soxhlet with MeOH, and higher than when DCM was used (371 ± 5 and 379 ± 12 µg g^?1 for PFE and Soxhlet, respectively). For both matrices, the PFE yields for oxy-PAHs were higher than those obtained with Soxhlet.     

Three new mussel tissue standard reference materials (SRMs) for the determination of organic contaminants

Three new mussel tissue standard reference materials (SRMs) have been developed by the National Institute of Standards and Technology (NIST) for the determination of the concentrations of organic contaminants. The most recently prepared material, SRM 1974b, is a fresh frozen tissue homogenate prepared from mussels (Mytilus edulis) collected in Boston Harbor, Massachusetts. The other two materials, SRMs 2977 and 2978, are freeze-dried tissue homogenates prepared from mussels collected in Guanabara Bay, Brazil and Raritan Bay, New Jersey, respectively. All three new mussel tissue SRMs complement the current suite of marine natural-matrix SRMs available from NIST that are characterized for a wide range of contaminants (organic and inorganic). SRM 1974b has been developed to replace its predecessor SRM 1974a, Organics in Mussel Tissue, for which the supply is depleted. Similarly, SRMs 2977 and 2978 were developed to replace a previously available (supply depleted) freeze-dried version of SRM 1974a, SRM 2974, Organics in Freeze-Dried Mussel Tissue. SRM 1974b is the third in a series of fresh frozen mussel tissue homogenate SRMs prepared from mussels collected in Boston Harbor starting in 1988. SRM 1974b has certified concentration values for 22 polycyclic aromatic hydrocarbons (PAHs), 31 polychlorinated biphenyl congeners (PCBs), and 7 chlorinated pesticides. Reference values are provided for additional constituents: 16 PAHs, 8 PCBs plus total PCBs, 6 pesticides, total extractable organics, methylmercury, and 11 trace elements. PAH concentrations range from about 2 ng g^–1 dry mass (cyclopenta[cd]pyrene) to 180 ng g^–1 dry mass (pyrene). PCB concentrations range from about 2 ng g^–1 dry mass (PCB 157) to 120 ng g^–1 dry mass (PCB 153). The reference value for total PCBs in SRM 1974b is (2020 ± 420) ng g^–1 dry mass. Pesticide concentrations range from about 4 ng g^–1 dry mass (4,4-DDT) to 40 ng g^–1 dry mass (4,4-DDE). SRM 2977 has certified values for 14 PAHs, 25 PCB congeners, 7 pesticides, 6 trace elements, and methylmercury. Reference values for 16 additional PAHs and 9 inorganic constituents are provided, and information values are given for 23 additional trace elements. SRM 2978 has certified and reference concentrations for 41 and 22 organic compounds, respectively, and contains contaminant levels similar to those of SRM 1974b. Organic contaminant levels in SRM 2977 (mussels from Guanabara Bay, Brazil) are typically a factor of 2 to 4 lower than those in SRM 1974b and SRM 2978. The organic contaminant concentrations in each new mussel tissue SRM are presented and compared in this paper. In addition, a chronological review of contaminant concentrations associated with mussels collected in Boston Harbor is discussed as well as a stability assessment of SRM 1974a.Electronic Supplementary Material Supplementary material is available in the online version of this article at . A link in the frame on the left on that page takes you directly to the supplementary material.     

Polychlorinated naphthalene concentrations and profiles in cheese and butter,and comparisons with polychlorinated dibenzo-p-dioxin,polychlorinated dibenzofuran and polychlorinated biphenyl concentrations

Polychlorinated naphthalenes (PCNs) are candidates for inclusion in the Stockholm Convention on persistent organic pollutants. PCNs are structurally and toxicologically similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and its analogues. Intake in food is considered to be an important human exposure pathway for PCNs. In this preliminary study, cheese and butter samples were analysed for PCNs, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) using an isotope dilution gas chromatography high-resolution mass spectrometry method. The aim of this study was to evaluate the PCN concentrations in the cheese and butter samples and to compare them with the PCDD, PCDF and PCB concentrations. The PCN concentrations were 5.6–103 pg g^?1 of wet weight in the seven cheese samples tested and 5.0–199 pg g^?1 of wet weight in the seven butter samples tested. The mass concentrations of lower chlorinated congeners were greater than those of the higher chlorinated congeners. Congeners of CN45/36, CN27/30 and CN33/34/37 were much more abundant than other congeners found in tetrachlorinated PCNs. Congeners of CN51, CN66/67 and CN73 were determined to be the predominant congeners in penta-, hexa- and heptachlorinated homologs, respectively. The PCNs contributed around 5% of the total PCN, PCDD, PCDF and PCB toxic equivalence (TEQ) values. CN73 was found to be the dominant PCN congener and contributed more than 40% to the PCN TEQ value. Congeners CN66/67, CN69 and CN63 were also found at relatively high levels. The PCB congener CB118 was the predominant congener (by mass-based concentration) of the 12 dioxin-like PCBs (dl-PCBs). The PCBs contributed 53.8% of the total TEQ, and congener CB126 contributed more than any other compound that was analysed to the total TEQ. The PCDDs and PCDFs contributed 11.6% and 29.7% of the total TEQ values, respectively.     

Trace analysis of benzophenone-derived compounds in surface waters and sediments using solid-phase extraction and microwave-assisted extraction followed by gas chromatography–mass spectrometry

This study describes a procedure for determining eight benzophenone-derived compounds in surface waters and sediments. These include the pharmaceutical ketoprofen, its phototransformation products 3-ethylbenzophenone and 3-acetylbenzophenone, and five benzophenone-type ultraviolet (UV) filters. The proposed analytical method involves the pre-concentration of water samples by solid-phase extraction (SPE) and microwave-assisted extraction (MAE) of sediment samples followed by derivatization and analysis by gas chromatography–mass spectrometry. Different parameters were investigated to achieve optimal method performance. Recoveries of 91 to 96 % from water samples were obtained using HLB Oasis SPE cartridges, whereas MAE of sediments (30 min at 150 °C) gave recoveries of 80 to 99 %. Limits of detection were between 0.1 and 1.9 ng L^?1 for water samples and from 0.1 to 1.4 ng g^?1 for sediment samples. The developed method was applied to environmental samples and revealed the presence of UV filters in the majority of the surface waters with up to 690 ng L^?1 of 2-hydroxy-4-methoxybenzophenone. By contrast, ketoprofen (≤2,900 ng L^?1) and its degradation products (≤320 ng L^?1) were found in only two rivers, both receiving wastewater treatment plant effluents. Sediment analysis revealed benzophenone to be present in concentrations up to 650 ng g^?1, whereas concentrations of other compounds were considerably lower (≤32 ng L^?1). For the first time, quantifiable amounts of two ketoprofen transformation products in the aqueous environment are reported.     

Determination of Organochlorine Pesticide Residues in Sesame Seeds by GC-ECD

A method for the multiresidue analysis of 12 organochlorine pesticides in sesame seeds has been developed. The organochlorine residues in the seeds were first extracted by accelerated solvent extraction and the extract subjected to gel permeation chromatography to remove larger molecular weight materials such as proteins and waxes. The purified extract after gel permeation chromatography was analyzed by GC-ECD. Recoveries were higher than 75% for all compounds with relative standard deviations <20%. The limit of detection and limit of quantification were 1.6–3.3 and 5–10 ng g^?1, respectively.     

Chitosan-poly(m-phenylenediamine)@Fe3O4 nanocomposite for magnetic solid-phase extraction of polychlorinated biphenyls from water samples

A extraction medium based on chitosan-poly(m-phenylenediamine) (CS-PPD) @Fe₃O₄ nanocomposite was synthesized by chemical polymerization of m-phenylenediamine in the presence of chitosan coated magnetic nanocomposite, and for the first time, used as the sorbent for the magnetic solid-phase extraction (MSPE) of seven polychlorinated biphenyls (PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) at trace levels in water samples. Gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) was used for PCBs quantification and detection. Several factors related to MSPE efficiencies, such as type and amount of sorbent, extraction time, sample pH, and desorption conditions were investigated. Under the optimized conditions, an excellent linearity was observed in the range of 1.0–200 ng L^–1 for PCB180, 0.5–200 ng L^–1 for the other six PCBs with the correlation coefficients ranging from 0.9954 to 0.9993. The good recoveries at spiked levels of 10.0, 20.0, and 50.0 ng L^–1 were obtained in the range of 94 %–108 %, and the coefficients of variations were less than 6 %. The proposed method was feasible, rapid, and easy to operate for the trace analysis of the PCBs in local aquaculture water, livestock breeding water, and sewage water samples. Graphical Abstract

Fig. 1 Schematic diagram for the preparation of chitosan–poly(m-phenylenediamine) @Fe₃O₄ nanocomposite.     

Determination of Organochlorine Pesticide Residues in Sesame Seeds by GC-ECD

A method for the multiresidue analysis of 12 organochlorine pesticides in sesame seeds has been developed. The organochlorine residues in the seeds were first extracted by accelerated solvent extraction and the extract subjected to gel permeation chromatography to remove larger molecular weight materials such as proteins and waxes. The purified extract after gel permeation chromatography was analyzed by GC-ECD. Recoveries were higher than 75% for all compounds with relative standard deviations <20%. The limit of detection and limit of quantification were 1.6–3.3 and 5–10 ng g⁻¹, respectively.

     

Measuring mercury in wood: challenging but important

Mercury (Hg) in tree wood has been overlooked, in part because concentrations are so low as to be below detection limits of some analytical methods, but it is potentially important to forest ecosystem processes and budgets. We tested methods for the preparation and determination of Hg in tree wood by analysing samples of four tree species at the Hubbard Brook Experimental Forest, New Hampshire, USA, using thermal decomposition, catalytic conversion, amalgamation and atomic absorption spectrophotometry (USEPA Method 7473). Samples that were freeze-dried or oven-dried at 65°C were suitable for determination of Hg, whereas oven-drying at 103°C resulted in Hg losses, and air-drying resulted in Hg gains, presumably due to sorption from indoor air. Mean (±SE) concentrations of Hg tree bole wood were 1.75 ± 0.14 ng g^?1 for American beech, 1.48 ± 0.23 ng g^?1 for sugar maple, 3.96 ± 0.19 ng g^?1 for red spruce and 4.59 ± 0.06 ng g^?1 for balsam fir. Based on these concentrations and estimates of wood biomass by species based on stand inventory, we estimated the Hg content of wood in the reference watershed at Hubbard Brook to be 0.32 g ha^?1, twice the size of the foliar Hg pool (0.15 g ha^?1). Mercury in wood deserves more attention and is feasible to measure using appropriate techniques.     

Determining PAHs and PCBs in aqueous samples: finding and evaluating sources of error

This work describes the problems that occur during routine multi-step determinations of polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), which can be present at trace levels in water, and identifies sources of analyte losses at particular steps during the analytical procedure. PAH and PCB adsorption onto the walls of the container ranged from 0 to 70%. PAH and PCB recoveries of >70% were achieved during the LLE and SPE extraction steps. During the process of enriching the dichloromethane extract with PAHs and PCBs, based on the gentle evaporation of solvent, losses were <24% and <19%, respectively. Model experiments show that neither isolation of PAHs and PCBs (performed using either LLE or SPE) nor extract enrichment reduce the reliability of PAH and PCB determination. The steps that lead to the greatest loss of analyte are the ones that involve sampling, transport and storage of the water samples.     

Feasibility of hydrofluoric acid etched sand particles for enrichment and determination of polychlorinated biphenyls at trace levels in environmental water samples

This study aims to investigate the feasibility of etched sand particles being used as solid-phase extraction adsorbents to enrich polychlorinated biphenyls (PCBs), which are typical persistent organic pollutants in the environment, at trace levels. Gas chromatography–tandem mass spectrometry was selected to detect the compounds. Etched sand particles exhibited excellent merits on the enrichment of PCBs. Related important factors affecting extraction efficiencies were investigated and optimized in detail. Under optimized conditions, low limits of detection (0.42 to 3.69 ng L^?1), wide linear range (10 to 1,000 ng L^?1), and high repeatability (1.9 to 8.2 %) were achieved. The developed method was validated with several real water samples, and satisfactory results were obtained. All of these findings indicate that etched sand particles would be useful for the enrichment and determination of organic pollutants at trace levels in water samples.     

Temporal variation of atmospheric polycyclic aromatic hydrocarbon concentrations in PM10 from the Kathmandu Valley and their gas-particle concentrations in winter

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM) with a diameter <10 µm (PM₁₀, 50% cut off) were investigated in the Kathmandu Valley, Nepal, during 2003. In order to understand the dynamics of atmospheric PAHs in winter, the PAH concentrations in total PM and in the gaseous phase were investigated in the valley in December 2005. Total of 45 PAH compounds (∑45PAHs) were analysed by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). In 2003, the ∑45PAH concentrations in PM₁₀ ranged between 4.3 and 89 ng m^?3 (annual average; 27 ± 24 ng m^?3). The average concentrations of ∑45PAHs in December 2005 were 210 ± 33 ng m^?3 in total PM and 430 ± 90 ng m^?3 in the gaseous phase. The ∑45PAH concentration in PM accounted for more than 30% of the sum of their particulate and gaseous forms. Phenanthrene (Ph) was the most predominant compound in the gaseous phase, whereas four- to seven-ring PAHs were predominant in total PM. The highest values of ∑45PAHs occurred in the winter and spring. Estimates of emission sources based on diagnostic molecular ratios showed that atmospheric PAHs in the Kathmandu Valley mainly originated from the exhaust gas of diesel engine. In the winter and spring, PAH pollution would be accelerated by the operations of brick kilns and the frequent formation of an atmospherically stable layer in the valley.     

Determination of pharmaceutical compounds in sewage sludge using a standard addition method approach

An analytical method for the simultaneous determination of eight pharmaceutical compounds in biosolids from urban wastewater treatment plants (WWTPs) was developed and validated. The compounds evaluated were non-steroidal anti-inflammatory drugs (naproxen, diclofenac, and ibuprofen), lipid regulators (clofibric acid), and antibiotics (sulfathiazole, sulfapyridine, sulfamethazine, and sulfamethoxazole). Ultrasound assisted extraction with a water–methanol solvent mixture (1:1, v:v) was performed and the compounds were then determined by liquid chromatography coupled with tandem mass spectrometry. The design of the method was based on the application of the standard addition calibration methodology to reduce matrix interferences. Validation procedures were conducted with rabbit excrements as blank samples. Recoveries of the target analytes ranged from 76 to 131% in spiked samples at 50, 200 or 1000 ng g^?1 dry weight (dw). The relative standard deviations were in the range of 5–15% and the method detection limits ranged from 2 to 12 ng g^?1dw. The method was applied to monitor pharmaceutical concentrations in biosolids from different WWTPs over an eight-month period (May to December 2011). Diclofenac, sulfapyridine and ibuprofen were detected in most of the samples whereas sulfamethazine and ibuprofen were the pharmaceuticals found in the highest concentrations (>200 ng g^?1 dw on average).     

Analysis of Dried Blood Spots for Polychlorinated Biphenyls and Organochlorine Pesticides by Gas Chromatography Coupled with Tandem Mass Spectrometry

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) are anthropogenic pollutants highly resistant to chemical degradation and readily absorbed by organic tissue. Their persistence in the environment and toxicological threat to mammals prompts swift, reliable methods of analysis. This study outlines a rapid, efficient and sensitive, validated methodology utilizing a simple liquid extraction technique, and subsequent analysis by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) for the determination of PCBs and OCs from dried blood spots. The PCBs and OCs were quantified in whole marine mammal blood spotted on Whatman Protein Saver cards (PSCs) by extracting the analytes into acetonitrile acidified with formic acid, followed by GC-MS/MS analysis. The samples were analyzed in positive electron impact (EI+) ionization mode with the electron energy set to 40?eV to preserve analyte integrity. Fortified blood with the analytes of interest was used for method validation and subsequent sample screening. The recoveries of targeted analytes ranged from 62.5% to 107.8%, with relative standard deviations ranging from 0.09% to 4.6% at a 100?ng·mL^?1 concentration level. The method detection limits were from 40.4?ng·g^?1 to 179.2?ng·g^?1 for the PCBs and 37.6?ng·g^?1 to 145.1?ng·g^?1 for the OCs. The use of dried blood spots provided for numerous advantages compared to whole blood samples while demonstrating reduced matrix effects and enhanced sample lifespan while retaining analyte sensitivity.