New method for the analysis of lipophilic marine biotoxins in fresh and canned bivalves by liquid chromatography coupled to high resolution mass spectrometry: a quick, easy, cheap, efficient, rugged, safe approach.

A new method for the analysis of lipophilic marine biotoxins (okadaic acid, dinophysistoxins, azaspiracids, pectenotoxins, yessotoxins, spirolids) in fresh and canned bivalves has been developed. A QuEChERS methodology is applied; i.e. the analytes are extracted with acetonitrile and clean-up of the extracts is performed by dispersive solid phase extraction with C18. The extracts are analyzed by ultra-high performance liquid chromatography coupled to a hybrid quadrupole-Orbitrap mass spectrometer, operating in tandem mass spectrometry mode, with resolution set at 70,000 (m/z 200, FWHM). Separation of the analytes, which takes about 10min, is carried out in gradient elution mode with a BEH C18 column and mobile phases based on 6.7mM ammonia aqueous solution and acetonitrile mixtures. For each analyte the molecular ion and 1 or 2 product ions are acquired, with a mass accuracy better than 5ppm. The quantification is performed using surrogate matrix matched standards, with eprinomectin as internal standard. The high-throughput method, which has been successfully validated, fulfills the requirements of European Union legislation, and has been implemented as a routine method in a public health laboratory.

Comparison of triple quadrupole mass spectrometry and Orbitrap high-resolution mass spectrometry in ultrahigh performance liquid chromatography for the determination of veterinary drugs in sewage: benefits and drawbacks.

This paper presents a comparison of triple quadrupole tandem mass spectrometry (MS/MS) and Orbitrap high-resolution mass spectrometry (HRMS) combined to ultrahigh performance liquid chromatography for the determination of glucocorticoids and polyether ionophores in sewage, in order to show the major benefits and drawbacks for each mass spectrometry analyser. Overall, HRMS measurements have enhanced performance in terms of confirmatory capabilities than MS/MS measurements. Moreover, similar limits of quantification, limits of detection, linear range and repeatability for glucocorticoids with both the MS/MS and HRMS methods were compared, but in the case of polyether ionophores, slightly better limits of detection and limits of quantification were obtained with the HRMS method because of the high sensitivity obtained when diagnostic ions are used for quantification instead of selected reaction monitoring transitions for these compounds. The two methods have been applied to the analysis of several influent and effluent sewage samples from sewage treatment plants located in the Tarragona region (Catalonia, Spain), showing an excellent correlation between the two methods.

Evaluation of antibiotic mobility in soil associated with swine-slurry soil amendment under cropping conditions.

Interest in identifying pools of antibacterial-resistance genes has grown over the last decade, with veterinary antibiotics (VAs) receiving particular attention. In this paper, a mesoscale study aimed at evaluating the vertical transport of common VAs-namely, fluoroquinolones, tetracyclines, sulfonamides, and lincosamides in agricultural soil subjected to drip irrigation-was performed under greenhouse conditions. Accordingly, leachates of cropped and uncropped soil, amended with swine-slurry leading to 19-38 µg kg(-1) (dry mass) antibiotics in the soil, were analyzed over the course of the productive cycle of a lettuce (42 days) with three sampling campaigns (N = 24). High lincomycin (LCM) concentrations (30-39 µg L(-1)) were detected in the leachates collected from the swine-slurry-amended soil. The highest LCM mass recovered in the leachates (30.1 ± 1.63 %) was obtained from cropped experimental units. In addition, the LCM leaching constant and its leaching potential as obtained from the first-order model were higher in the leachates from the cropped experimental units. Lower concentrations of sulfadimethoxine were also detected in leachates and in soil. Enrofloxacin and oxytetracycline occurred only in soil, which is consistent with high soil interaction.

Persistent organic pollutants (POPs) in sediments from fishing grounds in the NW Mediterranean: ecotoxicological implications for the benthic fish Solea sp.

Sediment polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorinated pesticides (OCls) and polybrominated diphenyl ethers (PBDEs) were measured during winter 2011 at seven sites on the Catalan coast (NW Mediterranean). Also at these sites, the benthic fish Solea solea and Solea senegalensis were fished for biomarker analysis. Chemical concentrations did not exceed the values considered safe by sediment quality guidelines (SQGs) for PAHs. However, levels of DDT (94.5 ng/g d.w.) and PCBs (15.1 ng/g d.w.) were significant in the Ebre Delta. Nonspecific immune parameters in S. solea showed a positive correlation between lysozyme activity in plasma and PAH content in sediment (r=0.982, p<0.01) and the opposite trend occurred with the complement test (ACH50) (r=-0.837; p<0.05). Cell counts (monocytes, lymphocytes and granulocytes) were elevated at most PAH-affected sites. A high concentration of bile FACs (fluorescent aromatic compounds) occurred at the northern station.

Assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans in sludges according to the European environmental policy.

The amount of sewage sludge generated in Europe is expected to surpass the 10 million tons/year in 2006 as a result of the waste water treatment process according to the Water Policy in European Union. Sewage sludge is what is left behind after water is cleaned in waste treatment plants and is characterized for this high content in nitrogen and phosphorous that could be of great importance in agriculture as fertilizer or soil conditioner. On the other hand, pollutants like metals and organic contaminants are usually removed from water and are accumulated in the sewage sludge, reaching the food chain if their concentrations are not below the safe limits established by the European legislation. The latter issue is of great concern nowadays and in this sense, different works alert against the use of the sewage sludge in agriculture arguing that serious illnesses, even resulting in death as well as adverse environmental impacts are associated to the application of sewage sludge. This work is a continuation of a former comprehensive survey on of priority organic pollutant in sludges for agricultural purposes carried out by our group in Catalonia and this time is focused on the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), one of the most toxic group of organic compounds listed in the Work Document on Sludge which is the reference tool in this field in Europe and is also included in the Stockholm Convention. Eighty eight samples were collected from the end of 2003 to April 2006 and the concentrations detected were lower than the 100 ng/kg I-TEQ limit recommended by the European legislation (EC, 2000). Thus, sewage sludges generated in Catalonia do not represent a threat to human health if they are used as fertilizers in agriculture.

Organic compounds temporal trends at some invertebrate species from the Balearics, Western Mediterranean.

Concentrations of persistent organic pollutants (POPs) such as hexachlorobenzene (HCB), dichlore diphenyl trichloretane (DDT), polychlorinated biphenyls (PCBs), and gamma-hexachlorocyclohexane (gamma-HCH or lindane) were determined in tissue of marine benthic invertebrates such as Mytilus galloprovincialis, Chamelea gallina, Venus verrucosa, Lithophaga lithophaga and Paracentrotus lividus. Species were selected due to their habitat, trophic level, feeding behaviour and their consumption. Invertebrate species were systematically sampled from December 1996 to December 2005 from several sites along the Balearic Islands. The highest concentrations of PCBs (785ng/g lipid) were found in M. galloprovincialis while the lowest concentrations were found in the sea-urchin P. lividus (193ng/g lipid). Among the 7 PCB quantified congeners the higher values are mainly obtained for CB138 and CB153. All bivalves presented higher PCBs contents than the sea-urchin P. lividus are possibly linked with the bioaccumulation process of POPs throughout the food web and to differential detoxifying mechanisms. The concentration of SigmaDDT exceeds that of HCB and gamma-HCH at all species and sampling stations. DDT concentrations ranged from 0.4ng/g ww at the bivalve C. gallina in 2002, to values of 15.8ng/g ww at the bivalve L. lithophaga in 1998. The values obtained for the organic compounds (HCH, HCB, PCBs, DDT) depend upon the place and year of sampling and are compared to values found by other authors for the mussel M. galloprovincialis in other Mediterranean areas. gamma-HCH and HCB were found in lower concentrations than the other POPs.

Polychlorinated dibenzo-p-dioxins, dibenzofurans and 'dioxin-like' PCBs in flue gas emissions from municipal waste management plants.

The aim of this work is to give representative data on polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyl (PCBs) from stack gas emissions of an urban solid waste management plant which has to comply with the limit of 0.1 ng I-TEQ/Nm3. In particular, the study is focused on 29 target compounds, the seventeen 2,3,7,8-PCDDs/Fs, four non-ortho PCBs and eight mono-ortho PCBs which configure so-called 'dioxin-like' PCBs (DL-PCBs). To this end, emission measurements were performed during one year over the three operating combustion lines in a selected waste management plant. In general, accurate methodology allowed characterizing all target compounds in almost all the samples analyzed. In addition, a typical pattern for DL-PCBs is reported. The pattern presented PCB #118 to be the highest, nevertheless the figures demonstrated DL-PCBs contribution to the total TEQ around 3% being PCB #126 the most important congener due to its TEF of 0.1. Finally, remarkable differences were achieved in comparison with both environmental and biological samples such as soils, sediments, human milk or fish since these matrices may present DL-PCB contribution to the total TEQ up to 77%.

Priority organic pollutant assessment of sludges for agricultural purposes.

A comprehensive characterization of five of the seven priority organic pollutants listed in the draft of the "Working document on sludge" [EU, 2000. Working Document on Sludge 3rd Draft. Unpublished, 19 p] has been carried out during 2001-2003 in sludge samples from Catalonia (NE Spain). One hundred and thirty-nine samples belonging to 20 Waste Water Treatment Plants (WWTPs), seven sludge treatment (thermal drying) and three composting sludge plants were taken in order to determine the concentration of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs), di-2-(ethyl-hexyl)-phthalate (DEHP), nonylphenol and nonylphenol ethoxylates with one or two ethoxy groups (NPE), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). PCDD/F concentrations were in general lower than the 100 ng I-TEQ/kg limit suggested in the above-mentioned document. In the same way, 98.5% for PCBs, 97% for PAH and 92.8% for DEHP of the samples presented concentrations lower than 0.8 mg/kg dm, 6 mg/kg dm and 100 mg/kg dm, respectively. In contrast, the vast majority of samples contained NPE concentrations much higher than 50mg/kg dm limit. The values ranged from 14.3 to 3150 mg/kg dm (median value=286.6 mg/kg) being composted sludge samples the less contaminated ones (17.9-363.4 mg/kg dm; median value=89.3 mg/kg). Special attention should be paid to the Catalan sludge NPE contamination owing to the high levels detected.

Temporal trends of PCDDs/PCDFs in ambient air in Catalonia (Spain).

This paper reports the results of an assessment of dioxin levels in ambient air in samples collected in the four provinces of Catalonia (Spain) performed by the Environment Department of the Autonomous Government of Catalonia and the Spanish Council for Scientific Research (CSIC). The study includes compiled data of more than 133 samples collected in 28 different sites (rural, urban, suburban and industrial) between 1994 and 2002. The levels revealed a variable content of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) depending both on the area and the contamination source. Thus, concentrations from 16 to 954 fg I-TEQ/Nm(3), with a mean value of 180 fg I-TEQ/Nm(3), were determined in industrial areas. The levels found in urban and suburban sites varied from 10 to 357 fg I-TEQ/Nm(3), with a mean value of 80 fg I-TEQ/Nm(3). The lowest concentrations were found in rural areas, ranging from 5 to 125 fg I-TEQ/Nm(3), with a mean value of 42 fg I-TEQ/Nm(3). As part of the project, levels of samples collected in parallel using two different samplers, a total suspended particulate (TSP) sampler and PM10 sampler, were compared. The results of 11 different campaigns indicated that both methods are comparable and no significant differences were determined.

An episode of dioxin contamination in feedingstuff: the choline chloride case.

In 2000, as part of a survey programme, the German authorities detected high levels of dioxins in a choline chloride (CC) premix used as animal food component. The contaminated additive consisted of different products of mineral and vegetable origin acting as a carrier. The CC was manufactured in Belgium. The final product was produced in and distributed from a plant in Spain. The German authorities informed all European Community members of the incident. The Spanish Ministry of Agriculture, Fisheries and Food and the Regional Authorities immediately conducted a survey in collaboration with the Spanish Council for Scientific Research (CSIC) to determine and isolate the source of the contamination. Analysis of a large number of samples of pure CC, pine sawdust, almond shell and other substances currently used in the preparation of the premix confirmed the presence of a significant amount of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans in mixtures in which pine sawdust was present. An analysis of the congener profiles revealed similarities with those found in technical pentachlorophenol (PCP) formulations. The conclusion was that PCP-contaminated sawdust as carrier for CC was source of dioxin contamination in feedingstuff.

Time and space patterns of volatile organic compounds in a sewage treatment plant.

47 regulated and non-regulated volatile organic compounds (VOCs) were characterised by closed-loop stripping analysis (CLSA) and high resolution gas chromatography coupled to mass spectrometry (HRGC/MS) in 28 aqueous samples from 4 sampling points along a sewage treatment plant in Manresa, Catalonia, Spain. A 4 x 2(2) factorial design (16 samples) was first prepared for the sampling, and reinforced with 12 additional samples at the plant influent. The total analyte weighted mean concentration was 232 microg x l(-1) at the plant influent, with a mass flow of 2231 kg x yr(-1). Petroleum solvents and terpenic compounds accounted for 79% of the influent analyte concentration. VOC concentration in influent was clearly higher for most VOCs from 12 to 22 h (high organic load hours), and lower from 24 to 10 h (lower organic load). Differences between time bands were confirmed through t tests. Differences between weekdays and the weekend were not so clear, and could not be confirmed through t tests. VOC concentrations along the plant are discussed. Overall analyte removal in the plant was 89%.

Estimating DOC regime in a wastewater treatment plant by UV deconvolution.

A UV-deconvolution method was modified, and applied to estimation of dissolved organic carbon (DOC) along a municipal wastewater treatment plant (WWTP) in Catalonia, Spain. One grab sample was taken every 2h at four sampling points, for 1 week (336 samples), in order to characterise day/night and weekday/weekend DOC regimes along the plant. Samples were centrifuged before DOC determination or estimation. Four components were selected for describing wastewater composition and spectra. Reference spectra for these components were taken from the literature and proved to correctly explain the sample spectra. A two-step deconvolution method was developed, which avoided negative nitrate coefficients while keeping deconvolution error low. The calibration file for DOC estimation was determined by analysing DOC and acquiring UV spectra from 48 samples. DOC values were correlated to UV spectra by multiple linear regression. Determination coefficient and standard error were comparable to the values found in the literature. In raw or diluted samples with an absorbance between 2.0 and 2.5, DOC was probably underestimated by the method. This points to some nonlinearity for absorbances above 2.0, rather than the 2.5 limit suggested by the original method. DOC calculation through UV deconvolution allowed for the estimation of DOC regime along the WWTP. Time bands for higher and lower DOC concentrations were determined and characterised at each sampling point, for weekdays and the weekend. Except for the plant effluent, clear time bands were found. In effluent, DOC was always low, and very small oscillations were detected, due to DOC removal and intense mixing in the biological process. DOC profiles at each point are discussed in this paper. The modified deconvolution method has proved to be an accurate and efficient technique for estimating DOC of a large number of raw and diluted samples.

A comparison of TEQ contributions from PCDDs, PCDFs and dioxin-like PCBs in sewage sludges from Catalonia, Spain.

Eight sewage sludges from rural, urban and industrial wastewater treatment plants (WWTPs) in Catalonia (Spain) were analysed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) to determine the present levels of contamination. A method based on an automated cleanup system followed by an isotope-dilution high-resolution mass spectrometric analysis was employed. Total toxicity equivalent (WHO-TEQ) values were calculated using the toxicity equivalent factors (WHO-TEFs) proposed by WHO for dioxin-like PCBs, PCDDs and PCDFs. The WHO-TEQ(PCDD/F) values for these samples ranged from 4.9 to 20.8 pg/g dry weight (d.w.), with a mean value of 9.3 pg/g d.w., whereas WHO-TEQ(PCB) levels ranged between 1.9 and 6.6 pg/g d.w., with a mean value of 4.2 pg/g d.w. The WHO-TEQ(PCB) contribution varied from 13% to 50%, suggesting that PCB contribution on the toxicity of the samples must be taken into account. Moreover, these contemporary PCDD, PCDF and PCB concentrations were compared with previous data obtained from sewage sludge samples collected during the 80s. Our findings show that contemporary PCDD, PCDF and PCB levels have declined since the 80s.

Determination of PCDDs and PCDFs in different animal feed ingredients.

As result of a study to control feedstuff, analyses were carried out to evaluate the contamination caused by PCDDs and PCDFs in different animal feed ingredients. Thirty two samples were selected, including ingredients of animal and mineral origin. For samples of mineral origin, some additives widely employed as binder and anticaking agents, such as bentonite, damoline, kaolin, magnesite, sepiolite and zeolite were selected. And, for ingredients of animal origin, samples of hemoglobin, animal fat, fish oil, fish meal and meat and bone meal were analyzed. The levels ranged from 0.52 to 9.08 pg WHO-TEQ/g fat for samples of animal origin, and from 0.05 to 460.59 pg WHO-TEQ/g for samples of mineral origin. The higher concentrations were observed for the kaolin samples that presented high levels of dioxin contamination.

Toxic potency of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in food samples from Catalonia (Spain).

A surveillance program on polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in 29 foodstuff samples produced all over the four provinces in Catalonia (Spain) is presented. The study included the analyses of milk, egg, meat (beef, chicken, and pork), mussel, and olive oil samples. A previously developed method for the simultaneous analysis of the 2,3,7,8-substituted PCDDs/PCDFs and the dioxin-like PCBs, as well as the indicator PCBs, was employed. Total toxicity equivalent (TEQ) values were calculated using the toxicity equivalent factors (TEFs) proposed by the World Health Organization (WHO) for dioxin-like PCBs, PCDDs, and PCDFs. The TEQ(PCDD/F) levels were below the limits proposed in the draft of the EC regulation for food commercialization in the European countries. These limits are the following: 2 pg WHO-TEQ/g fat for pork, 3 pg WHO-TEQ/g fat for milk and chicken, 5 pg WHO-TEQ/g fat for egg and beef, and 3 pg WHO-TEQ/g whole product for fish. The contributions of PCDDs/Fs and dioxin-like PCBs in the total toxicity of the samples were calculated for each matrix. The results showed that the TEQ(PCB) contribution varied from 27% in olive oil samples to 81% in mussel samples. These findings suggest that the regulation of TEQ contents in food should include not only the TEQ(PCDD/F), but also the TEQ(PCB).

Degradation of polyethoxylated nonylphenols in a sewage treatment plant. Quantitative analysis by isotopic dilution-HRGC/MS.

Polyethoxylated alkylphenols (APnEO, where n is the number of ethylene oxide molecules), are non-ionic surfactants widely used for domestic and industrial purposes. Most of APnEO are polyethoxylated nonylphenols (NPnEO). NPnEO are widespread environmental pollutants with relatively low toxicity for mammals and higher toxicity for aquatic organisms. In addition, they have been described as endocrine disrupters in recent publications. One of the main problems related to these surfactants is their uncomplete degradation, even in the most effective sewage treatment plants. Usually, the final products, more toxic and resistant to biological degradation than NPnEO, are nonylphenol (NP), monoethoxylated nonylphenol (NP1EO), diethoxylated nonylphenol (NP2EO), nonylphenoxy acetic acid (NP1EC), and nonylphenoxyethoxy acetic acid (NP2EC). In this paper, the degradation of NPnEO was studied in the different processes of a sewage treatment plant. For this purpose, NP, NP1EO and NP2EO were analysed in composite samples collected at different points along the plant (influent, pre-treatment effluent, primary effluent, plant effluent). Analyses were carried out by isotopic dilution-HRGC/MS, using available labelled nonylphenols (13C6-NP, 13C6-NP1EO, 13C6-NP2EO) as internal standards. Extraction of NPnEO from aqueous samples, previous to analysis, was performed by the Likens-Nickerson method (simultaneous steam distillation/solvent extraction, SDE).

Dioxin abatement strategies and mass balance at a municipal waste management plant.

Since the thermal management of municipal solid waste (MSW) is considered to be one of the major sources of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), the purpose of this study was to show the results of a dioxin abatement program performed in the municipal waste incineration (MWI) plant of Tarragona (NE Spain). Previously, stack gas emission levels of PCDDs/PCDFs around 3.26 ng I-TEQ/Nm3 were determined when the gas-cleaning system consisted only of an electrostatic precipitator (ESP). Decreased levels, below 0.1 ng I-TEQ/ Nm3, were observed when a new air pollution control system was installed. This new system was improved by the injection of activated carbon, which helped to lower the levels of PCDDs/PCDFs to around 0.01 ng I-TEQ/Nm3. Considering the absence of a particular impact on herbages, soils, and ambient air around the plant, as reported in previous works, and the hypothesis that a modern installation could become a sink for dioxins instead of a source, a dioxin mass balance was evaluated. The study compared in a large-scale MWI plant the levels of PCDDs/PCDFs of all input and output contributors (MSW, ambient air, stack gas emission, fly ash, and slag) forming part of the inventory collected in various monitoring campaigns. The findings revealed a remarkable homogeneity in output values (between 1.19 and 2.62 ng I-TEQ/yr) in contrast to the large variability observed in input values. In the first sampling campaign, the dioxin content in MSW was around 64.15 ng I-TEQ/kg, and a negative balance of 7.68 g I-TEQ/yr was calculated. However, in the latest campaign, levels were about 2.36 ng I-TEQ/kg MSW, resulting in a positive balance of 2.28 g I-TEQ/yr.

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in soil samples from Spain.

Soil analyses were carried out to evaluate the contamination caused by PCDDs and PCDFs in different soil samples. Monitoring was undertaken at different locations throughout Spain, from 1993 to 1999. A total of 230 samples were analysed. The levels ranged from 0.10 pg I-TEQ/g to 1.08 ng I-TEQ/g. Differences in dioxin levels were observed as a function of the sampling site, with levels at the industrial sites exceeding those at the control sites.

Evaluation of dioxin contamination in sewage sludge discharges on coastal sediments from Catalonia, Spain.

The fate of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in sewage sludges after discharge into the sea was investigated. Sediment samples were analysed at a sewage sludge disposal site as well as in the surrounding areas. Moreover, eight sediment samples from two rivers in Catalonia and three sediment samples from Catalonian Coast were analysed to determine the background levels of contamination. Total international toxicity equivalent (I-TEQ) values for these sediments ranged from 0.42 to 8.01 pg g, with a mean value of 4.15 pg/g and a median value of 3.69 pg/g. However, the I-TEQ values of sludge-treated areas were higher: 57.04 pg/g at the dumping site, and within a range of 13.42-47.76 pg/g near this site. Thus, European sediment quality objectives were exceeded. The higher concentrations coincided with changes in the ratio between PCDD and PCDF levels, suggesting the influence of the sewage sludge on coastal sediments.

Evaluation of an automated clean-up system for the isotope-dilution high-resolution mass spectrometric analysis of PCB, PCDD, and PCDF in food.

An automated clean-up system was evaluated for the simultaneous analysis of polychiorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF), and biphenyls (PCB) in different foods. In addition to the seventeen 2,3,7,8-substituted PCDDIPCDF and four non-ortho PCB, by use of the clean-up system studied, it was possible to collect the eight mono-ortho and two di-ortho PCB and the seven indicator PCB in two separate fractions during the same clean-up run. The study was first performed using standard mixtures containing PCDD, PCDF and PCB, and a certified reference material. The recoveries of the 13C-labeled compounds ranged from 51 to 90%, indicating that the PCDD, PCDF, and PCB clean-up worked satisfactorily. Next, the automated system for PCDD, PCDF, and PCB analysis was evaluated for foods such as milk, egg, meat (beef, chicken, and pork), mussel, and olive oil. The recoveries of the 13C-labeled compounds ranged from 40 to 120% for PCB and from 57 to 113% for PCDD/ PCDF, meeting the requirements of well accepted methods. Thus, the automated clean-up system studied is a suitable alternative to conventional clean-up methods.