Investigation of Galaxolide degradation products generated under oxidative and irradiation processes by liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry and comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry.

RATIONALE: Polycyclic musks have become a concern due to their bioaccumulation potential and ecotoxicological effects. The HHCB transformation product (TP) (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta[γ]-2-benzopyran; HHCB-lactone) is the most stable intermediate generated and it is frequently detected in river waters. The aim of this work was the identification of relevant TPs generated from UV irradiation and ozone treatments. METHODS: Identification of HHCB TPs was carried out by liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry (LC/ESI-QTOF-MS) and two-dimensional gas chromatography/electron impact time-of-flight mass spectrometry (GC×GC-EI-TOF-MS). With LC/ESI-QTOF-MS, TPs were characterized by means of mass accuracy in both full-scan and MS/MS modes through information-dependent acquisition (IDA) and direct injection on-column. With stir bar sorptive extraction (SBSE)-GC×GC-EI-TOF-MS, identification was based on the enhanced separation capacity and screening of unknowns through the acquisition of full-range mass spectra. RESULTS: The effectiveness of these complementary techniques allowed a detailed evaluation of the main TPs. Eighteen TPs were elucidated based on mass accuracy, in both full-scan and MS/MS modes using LC/ESI-QTOF-MS with mass errors below 5 ppm and 10 ppm (mostly), respectively. Most of the TPs had not been analytically identified in previous studies. Separation of the enantiomeric species (R) and (S) of HHCB-lactone, and the identification of other relevant TPs, was performed using SBSE-GC×GC-EI-TOF-MS. CONCLUSIONS: LC/ESI-QTOF-MS and GC×GC-EI-TOF-MS analysis provides the best alternative for TP identification of chemicals of concern, which have a wide range of polarities and isobaric compounds. A prediction of PBT (persistence, bioaccumulation and toxicity) using the PBT Profiler program suggested a classification of 'very persistent' and 'very toxic' for most of the TPs identified.

Qualitative and quantitative analysis of poly(amidoamine) dendrimers in an aqueous matrix by liquid chromatography-electrospray ionization-hybrid quadrupole/time-of-flight mass spectrometry (LC-ESI-QTOF-MS).

This work introduces a liquid chromatography-electrospray ionization-hybrid quadrupole/time-of-flight mass spectrometry (LC-ESI-QTOF-MS)-based method for qualitative and quantitative analysis of poly(amidoamine) (PAMAM) dendrimers of generations 0 to 3 in an aqueous matrix. The multiple charging of PAMAM dendrimers generated by means of ESI has provided key advantages in dendrimer identification by assignation of charge state through high resolution of isotopic clusters. Isotopic distribution in function of abundance of isotopes (12)C and (13)C yielded valuable and complementarity data for confident characterization. A mass accuracy below 3.8 ppm for the most abundant isotopes (diagnostic ions) provided unambiguous identification of PAMAM dendrimers. Validation of the LC-ESI-QTOF-MS method and matrix effect evaluation enabled reliable and reproducible quantification. The validation parameters, limits of quantification in the range of 0.012 to 1.73 µM, depending on the generation, good linear range (R > 0.996), repeatability (RSD < 13.4%), and reproducibility (RSD < 10.9%) demonstrated the suitability of the method for the quantification of dendrimers in aqueous matrices (water and wastewater). The added selectivity, achieved by multicharge phenomena, represents a clear advantage in screening aqueous mixtures due to the fact that the matrix had no significant effect on ionization, with what is evidenced by an absence of sensitivity loss in most generations of PAMAM dendrimers. Fig Liquid chromatography-electrospray ionization-hybrid quadrupole/time of flight mass spectrometry (LC-ESI-QTOF-MS) based method for qualitative and quantitative analysis of PAMAM dendrimers in aqueous matrix.

In vitro dose-response effects of poly(amidoamine) dendrimers [amino-terminated and surface-modified with N-(2-hydroxydodecyl) groups] and quantitative determination by a liquid chromatography-hybrid quadrupole/time-of-flight mass spectrometry based method.

This article presents a dose-response study of the effects of two types of third-generation (G3) and fourth-generation poly(amidoamine) (PAMAM) dendrimers on two cell lines (RTG-2 and H4IIE) by in vitro cytotoxicity assays with 3-(4,5-dimethylthizol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), neutral red uptake (NRU), and lactate dehydrogenase (LDH) assays. We particularly investigated the potential cytotoxic effect of positive surface charge, which a cationic amino-terminated PAMAM dendrimer can display, on the marked ability of PAMAM dendrimers to cross the cell membrane compared with PAMAM dendrimers functionalized with chains of N-(2-hydroxydodecyl). Quantification of dose-response effects was performed by use of mass spectrometry analysis. The analytical method using liquid chromatography-hybrid quadrupole/time-of-flight mass spectrometry that we developed allowed characterization of defective dendrimers instead of "ideal structures." Identification was based on accurate mass measurement, assignment of elemental composition, and the fully resolved (13)C/(12)C isotopic clusters of the multiply charged ions of PAMAM dendrimers. Validation of the liquid chromatography-mass spectrometry method made possible reliable and reproducible quantification of the extracellular and intracellular concentration of dendrimers at a micromolar level (limits of detection from 0.14 to 1.34 µM and from 0.43 to 1.82 µM in standard and culture medium, respectively). A higher cytotoxicity was found with the H4IIE cell line for surface-modified PAMAM dendrimers. The LDH assay was significantly more sensitive than the MTT and NRU assays, with half-maximal inhibitory concentrations (IC(50)) of 12.96 and 38.31 µg mL(-1) for surface-modified G3 and G4 dendrimers, respectively. No cytotoxic effects, in terms of IC(50), of amino-terminated PAMAM dendrimers were observed on both H4IIE and RTG-2 cells when the concentration was below 500 µg mL(-1) for G3 and G4 dendrimers.

Identification and measurement of veterinary drug residues in beehive products.

There is an increasing concern about the negative impacts of veterinary drugs in beehive compartments. This study evaluates the presence and distribution of chemical residues in beeswax, bee bread and honey and determinates in what extension honeybees are exposed to them. Samples were analyzed by LC-MS/MS and GC-MS/MS with a wide scope of 322 chemical residues. Samples were collected from apiaries located in rural and forest areas, showing no difference in contamination of phytosanitary applications. Residues of acaricides used for sanitary treatments, coumaphos and two transformation products of amitraz (DMF and DMPF), were quantified at higher levels in wax and bee bread than in honey in most cases. Coumaphos, DMF and DMPF were detected in honey in the range 6-36 µg.kg-1; 45-541 µg.kg-1; 15-107 µg.kg-1, respectively. All, except one sample, were below the EU MRLs, 396/2005 Regulation. Other pesticide residues were detected in beeswax and bee bread at various levels.

Exploration of environmental contaminants in honeybees using GC-TOF-MS and GC-Orbitrap-MS.

This study reports an analytical approach by gas chromatography and high-resolution mass spectrometry (HRMS) intended to be used for investigation of non-targeted environmental contaminants in honeybees. The approach involves a generic extraction and analysis with two GC-HRMS systems: time-of-flight and Orbitrap analyzers, GC-TOF-MS, and GC-Orbitrap-MS operated in electron-impact ionization (EI) mode. The workflow for screening of non-targeted contaminants consisted of initial peak detection by deconvolution and matching the first-stage mass spectra EI-MS with a nominal mass spectral library. To gain further confidence in the structural characterization of the contaminants under investigation, molecular formula of representative ions (molecular and fragment ions) was provided for those with an accurate mass scoring (error < 5 ppm). This methology was applied for screening environmental contaminants in 75 samples of adult honeybee. This approach has provided the tentative identification of environmental contaminants belonging to different chemical groups, among them, PAHs, phthalates and synthetic musks. Residues of veterinary treatments used in apiculture were also detected in the honeybee samples.

Identification of photocatalytic degradation products of bezafibrate in TiO(2) aqueous suspensions by liquid and gas chromatography.

In the present study the photocatalytic degradation of bezafibrate (BZF), a lipid regulator agent, has been investigated using TiO(2) suspensions and simulated solar light. The study focus on the identification of degradation products (DPs) using powerful analytical techniques such as liquid chromatography time of flight mass spectrometry (LC-TOF-MS), gas chromatography mass spectrometry (GC-MS), and high-performance liquid chromatography with diode-array detection (HPLC-DAD). Each technique provided complementary information that enabled the identification of 21 DPs. Accurate mass measurements obtained by LC-TOF-MS provided the elucidation of 17 DPs. Mass errors lower than 2mDa, allowed the assignment of empirical formula for the mayor DPs to be determined confidently. Three DPs were identified by GC-MS through the structural information provided by full scan mass spectra obtained by electron impact (EI) ionization and two more by HPLC-DAD by comparing the retention times (t(R)) and the UV spectra of the unknown DPs with those of commercial standards. Based on this by-product identification a possible multi-step degradation scheme was proposed. The pathways include single or multiple hydroxylation of BZF with subsequent phenoxy ring opening and the cleavage of the amide and ether bonds.

Removal of pharmaceuticals and kinetics of mineralization by O(3)/H(2)O(2) in a biotreated municipal wastewater.

The ozonation of an effluent from the secondary clarifier of two Municipal Wastewater Treatment Plants was performed by using alkaline ozone and a combination of ozone and hydrogen peroxide. Alkaline ozonation achieved only a moderate degree of mineralization, essentially concentrated during the first few minutes; but the addition of hydrogen peroxide eventually led to a complete mineralization. The evolution of total organic carbon (TOC) as a measure of the extent of mineralization and the concentration of dissolved ozone were analyzed and linked in a kinetic model whose parameter represented the product of the exposure to hydroxyl radicals and the kinetic constant of indirect ozonation. This rate parameter yielded the highest values during the first part of O(3)/H(2)O(2) runs. The kinetic constant for the decomposition of ozone at the end of the run was also measured and computed for the non-oxidizable water matrix and yielded essentially the same values regardless of whether or not hydrogen peroxide was used. A group of 33 organic compounds, mainly pharmaceuticals and some relevant metabolites present in the wastewater effluents, were evaluated before and after the ozonation process using a liquid chromatography-hybrid triple-quadrupole linear ion trap system (LC-QqLIT-MS). The results demonstrate that the ozonation degrades these compounds with efficiencies of over 99% in most cases, even under low mineralization conditions in alkaline ozonation.

Photodegradation of malachite green under natural sunlight irradiation: kinetic and toxicity of the transformation products.

This article describes the photolytic degradation of malachite green (MG), a cationic triphenylmethane dye used worldwide as a fungicide and antiseptic in the aquaculture industry. Photolysis experiments were performed by direct exposure of a solution of MG in water to natural sunlight. The main transformation products (TPs) generated during the process were identified by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) and gas chromatography mass spectrometry (GC-MS). The 28 TPs identified with this strategy indicate that MG undergoes three main reactions, N-demethylation, hydroxylation and cleavage of the conjugated structure forming benzophenone derivatives. These processes involve hydroxyl radical attack on the phenyl ring, the N,N-dimethylamine group and the central carbon atom. The Vibrio fischeri acute toxicity test showed that the solution remains toxic after MG has completely disappeared. This toxicity could be assigned, at least in part, to the formation of 4-(dimethylamine)benzophenone, which has an EC(50,30 min) of 0.061 mg l(-1), and is considered "very toxic to aquatic organisms" by current EU legislation.

Evaluation of ozone-based treatment processes for wastewater containing microcontaminants using LC-QTRAP-MS and LC-TOF/MS.

This article describes the development of an enhanced liquid chromatography-mass spectrometry (LC-MS) method for the analysis of a selected group of 57 organic contaminants in wastewater. This group comprises 39 pharmaceuticals belonging to different therapeutical classes and 10 of their most frequent metabolites. Six pesticides and two disinfectants were also included. The LC-MS method was developed using a hybrid quadrupole/linear ion trap (Q TRAP) analyzer operating in selected reaction monitoring (SRM) mode (in both positive and negative electrospray ionization) in combination with a time-of flight (TOF) mass analyser. The application of both techniques provided very good results in terms of accurate quantification and unequivocal identification. Quantification was based on the use of a linearly accelerating (LINAC) high-pressure collision cell, which enable the analysis of a high number of compounds with enough acquisition data points for an optimal peak definition in SRM. Unequivocal identification was provided by the acquisition of at least two SRM transitions and by obtaining accurate mass measurements of the identified compounds with errors lower than 2 ppm. As an alternative for compounds where a second transition cannot be detected by Q-Trap-MS, the application of survey scans in enhanced product ion (EPI) was evaluated. The analytical performance of the method was evaluated in effluent wastewater samples. Linearity of response over three orders of magnitude was demonstrated (R2>0.99 for most compounds). Matrix effects resulting in suppression of the response were frequently observed, between 2-50% for most of compounds, except 4-DAA and 4-AA, which exhibit higher values (68%). Signal enhancement was also detected in 16 compounds. Method limits of detection (LOD) were between 0.1-50 ng L(-1). Finally, the methodology was successfully applied to the evaluation of the efficiency of two ozone-based treatments applied to the effluent from the secondary clarifier of a municipal wastewater treatment facility. Preliminary results are presented demonstrating that ozonation of wastewaters degrade pharmaceuticals with a high efficiency. Removals higher than 90% were reached for most of target analytes.

Fast separation liquid chromatography-tandem mass spectrometry for the confirmation and quantitative analysis of avermectin residues in food.

A new residue analytical method for the confirmation and quantification of avermectin residues in food is described in this article. This method allows a fast analysis for the determination of avermectin residues, abamectin (ABM), ivermectin (IVM), emamectin benzoate (EMA) and doramectin (DOR) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Separation was performed using a short column of 1.8 microm particle size. The hybrid quadrupole/linear ion trap (QqQ(LIT)) system via the linearly accelerating (LINAC) high-pressure collision cell, allows the MS detection in multiple reaction monitoring (MRM) mode operating in fast scan acquisition times. The effect of reduced dwell times on mass spectral quality and sensitivity is evaluated in this study. For quantitative purposes, the influence of dwell time on S/N ratio and peak area was observed. ABM, IVM, EMA and DOR show an increased trend of peak area and S/N ratio, when dwell times are of 50 ms against 10-20 ms, suited when the number of compounds to be analyzed is higher. The sensitivity achieved by using the LC-MS/MS system is enough for the confirmation of avermectin residues in the selected commodities (salmon muscle and pepper) at trace concentration levels (sub-microg/kg and microg/kg) and therefore a sample pre-concentration step was not necessary. The instrumental limits of quantification (ILQ) are in the range of 0.15-5 ppb. Samples were extracted by solid-liquid extraction (SLE) procedure using acetonitrile, and cleaned-up using alumina. The average recoveries obtained were acceptable (80-95%). The calibration curves were linear over the working range from ILQs to 500 microg/kg. For the quantitative analysis, matrix-matched calibration and dilution of SLE extracts was proven as reliable alternative to compensate matrix-effects and for its feasible application in routine analysis.

Toxicity evaluation with Vibrio fischeri test of organic chemicals used in aquaculture.

The evaluation of acute toxicity by Vibrio fischeri test for different organic chemicals (antibiotics, pesticides, therapeutants, herbicides) commonly applied in aquaculture and a degradation product of surfactants, 4-nonylphenol, is presented in this work. Simazine, atrazine, emamectin benzoate and leucomalachite green have no toxic effects on V. fischeri at the concentration tested (up to 6mgl(-1)) which correspond to the maximum water solubility. Ciprofloxacin, terbutryn and deltamethrin, caused inhibition effects of 28%, 22% and 30% at concentrations up to 5mgl(-1). Toxic effects were not observed in the case of flumequine and oxolinic acid at the maximum concentration tested (0.189mgl(-1)). According to the toxicity categories established in the EU legislation, ciprofloxacin, terbutryn and deltamethrin could be considered non-harmful for V. fischeri. Malachite green and 4-nonylphenol are "very toxic to aquatic organisms" (EC(50,30min)=0.031mgl(-1) and 0.48mgl(-1), respectively). Carbaryl is "toxic to aquatic organisms" (2.4mgl(-1)). and glyphosate is harmful to V. fischeri (EC(50,30min)=44.2mgl(-1)). The matrix effect was evaluated comparing the toxicity measurements of the target compounds solubilized in seawater and distilled water. Malachite green, 4-nonylphenol and glyphosate, showed higher toxicity in distilled water than in seawater. Carbaryl was more toxic in seawater. All the compounds tested in seawater were not harmful at concentrations of ngl(-1) (10 and 50). However, 4-nonlylphenol and malachite green may act as toxic compounds in the environment at a low ppb level, since both may be detected in water at this concentration level.

Identification of non-intentionally added substances in food packaging nano films by gas and liquid chromatography coupled to orbitrap mass spectrometry.

The control of chemical migration from new functionalized food contact materials (FCMs) is a challenge for meeting food safety requirements. The non-intentionally added substances (NIAS) constitute a group of chemicals that are not applied, but may be introduced or formed during the production process of FCMs. This study describes a multi-analytical approach for the evaluation of unknown substances that migrate from FCMs. A case study is presented using a developed polymer consisting of a monolayer film with polylactic acid (PLA), polylimonene (PL) and zinc oxide nanoparticles (ZnO NPs). This approach incorporates the platforms of ICP-MS (inductively coupled plasma mass spectrometry), to determine whether there is transference of ZnO NPs used as antimicrobial agent and, the systems GC-MS and LC-MS (gas / liquid chromatography coupled to a quadrupole orbitrap mass spectrometer) for the characterization of the chemical structure of NIAS using the molecular mass and specific features of mass fragmentation. The screening of unknown compounds comprised retrospective analysis and data processing using both, a mass spectral library and databases, for GC and LC data, respectively. This approach has provided the tentative identification and quantification of seven NIAS, 3 by GC (Tripropylene glycol diacrylate, 10-Heneicosene and α-Tocopherol acetate) and 4 by LC (N,N-Diethyldodecanamide, N-[(9Z)-9-Octadecen-1-yl]acetamide, 1-Palmitoylglycerol and Glycerol stearate). This migration study was carried out according to the standard protocols established by EU regulation for FCMs.

Non-target evaluation of contaminants in honey bees and pollen samples by gas chromatography time-of-flight mass spectrometry.

This work presents a non-targeted screening approach for the detection and quantitation of contaminants in bees and pollen, collected from the same hive, by GC-EI-ToF-MS. It consists of a spectral library datasets search using a compound database followed by a manual investigation and analytical standard confirmation together with semi-quantitation purposes. Over 20% of the compounds found automatically by the library search could not be confirmed manually. This number of false positive detections was mainly a consequence of an inadequate ion ratio criterion (±30%), not considered in the automatic searching procedure. Eight compounds were detected in bees and pollen. They include insecticides/acaricides (chlorpyrifos, coumaphos, fluvalinate-tau, chlorfenvinphos, pyridaben, and propyl cresol) at a concentration range of 1-1207 µg kg-1, herbicides (oxyfluorfen) at a concentration range of 212-1773 µg kg-1 and a growth regulator hormone (methoprene). Some compounds were detected only in pollen; such as herbicides (clomazone), insecticides/acaricides and fungicides used to control Varroa mites as benzylbenzoate, bufencarb, allethrin, permethrin, eugenol and cyprodinil. Additional compounds were detected only in bees: flamprop-methyl, 2-methylphenol (2-49 µg kg-1) and naphthalene (1-23 µg kg-1). The proposed method presents important advantages as it can avoid the use of an unachievable number of analytical standards considered target compounds "a priori" but not present in the analyzed samples.

Determination of selected environmental contaminants in foraging honeybees.

Colony losses of honeybees have been of great concern in the last years. To explain these losses, several studies have been reported, and various factors, such as pathogens and pesticides, have been considered as possible causes. Nevertheless, organic contaminants, rather than pesticides, are continuously released to the environment, and can be intercepted by honeybees during foraging with the possible consequent damage. Azoles and organophosphorus esters have been selected in this work as environmental contaminants to be monitored in honeybees. A fast and robust method has been developed to determine these organic pollutants in honeybees. It is based on matrix solid phase dispersion (MSPD), which performs sample dispersion with extraction and clean up in the same step, followed by LC-ESI-MS/MS determination. Recoveries of the method varied between 73% and 119% and MQLs ranged from 0.8 to 4 ng g(-1). Honeybee samples from ten apiaries located in different regions were analyzed applying the developed method. Azole compounds were found at low levels, but not in all samples, while organophosphorus esters were found in most samples whatever location. Tris-(2-chloroisopropyl) phosphate, TCPP, and tributyl phosphate, TBP, were detected in all honeybees samples at levels higher than the rest of organophosphates analyzed.

Screening of environmental contaminants in honey bee wax comb using gas chromatography-high-resolution time-of-flight mass spectrometry.

This study reports an analytical approach intended to be used for investigation of non-targeted environmental contaminants and to characterize the organic pollution pattern of bee wax comb samples. The method comprises a generic extraction followed by detection with gas chromatography coupled to high-resolution time-of-flight mass spectrometry (GC-TOF-MS), operated in electron impact ionization (EI) mode. The screening approach for the investigation of non-targeted contaminants consisted of initial peak detection by deconvolution and matching the first-stage mass spectra EI-MS(1) with a nominal mass spectral library. To gain further confidence in the structural characterization of the contaminants under investigation, the molecular formula of representative ions (molecular ion when present in the EI spectrum) and, for at least other two fragment ions, was provided for those with an accurate mass scoring (mass error < 5 ppm). This methodology was applied for screening environmental contaminants in 50 samples of bee wax comb. This approach has allowed the tentative identification of some GC-amenable contaminants belonging to different chemical groups, among them, phthalates and polycyclic aromatic hydrocarbons (PAHs), along with residues of veterinary treatments used in apiculture.

Multiresidue method for the analysis of five antifouling agents in marine and coastal waters by gas chromatography-mass spectrometry with large-volume injection.

A simple multiresidue method has been developed for the determination of five pesticides, commonly used as active ingredients in antifouling paints, in seawater samples. The pesticides studied were: chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile), dichlofluanid (N-dimethyl-N-phenylsulphamide), Sea-Nine 211 (4,5-dichloro-2-n-octyl-4-isothazolin-3-one), Irgarol 1051 (2-methylthio-4-tert.-butylamino-6-cyclopropylamino-s-triazine) and TCMTB (2-thiocyanomethylthiobenzothiazole). The analytes were extracted from 200 ml water samples, using solid-phase extraction. A copolymer with hydrophilic-lipophilic balance was used as sorbent yielding good recoveries (82-95%) for most compounds except dichlofluanid and Sea-Nine 211 (<60%). Large volume injection (10 microl) gas chromatography and electron impact ionization MS (selected ion monitoring mode) detection enabled these compounds to be identified and quantified at the 1.2-3.0 ng/l level. Analysis of samples performed in three marinas in Almería (Spain) revealed the presence of Irgarol 1051 in all the cases, at concentration levels between 25 and 450 ng/l.

Analysis by liquid chromatography-electrospray ionization tandem mass spectrometry and acute toxicity evaluation for beta-blockers and lipid-regulating agents in wastewater samples.

This paper describes a multiresidue method for the extraction and determination of two therapeutic groups of pharmaceuticals, lipid-regulating agents (clofibric acid, bezafibrate, gemfibrocil, fenofibrate) and beta-blockers (atenolol, sotalol, metoprolol, betaxolol) in waters by solid-phase extraction followed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS). Recoveries obtained from spiked HPLC water, as well as, from spiked real samples (sewage treatment plants influent and effluents, river and tap water) were all above 60%, with the exception of betaxolol with a 52% recovery. The quantitative MS analysis was performed using a multiple reaction monitoring. The LC-MS-MS method gave detection limits ranging from 0.017 to 1.25 microg/l in spiked effluent. Precision of the method, calculated as relative standard deviation, ranged from 3.7 to 18.5%. Individual and combined effects on Daphnia magna were evaluated for both therapeutic groups. Individual effects in culture medium showed these compounds as not harmful and not toxic, an exception is fenofibrate that was found to be harmful, but at high, in the environment unrealistic concentrations (EC50 of 50 mg/l). Combined effect in wastewater showed synergistic toxic effects at low concentration level (2 microg/l).

Comparative study of analytical methods involving gas chromatography-mass spectrometry after derivatization and gas chromatography-tandem mass spectrometry for the determination of selected endocrine disrupting compounds in wastewaters.

Two GC-MS methods, based on the application of N,O-bis(trimethylsilyl)trifluoroacetamide-derivatization-GC-MS (selected-ion monitoring) and GC-MS-MS without derivatization, respectively, were optimised and applied to the determination of a group of five selected endocrine disrupting compounds (EDCs) in wastewaters. Both methods included solid-phase extraction with Oasis HLB cartridges allowing an enrichment factor for wastewater samples of 100-fold. The investigated EDCs were estrone, 17beta-estradiol, 17alpha-ethynylestradiol, 4-tert-octylphenol and bisphenol A. Results obtained from the validation studies yielded comparable results in both cases. Recoveries in spiked wastewaters at 50 ng/l were higher than 90% for all the compounds, except for 4-tert-octylphenol (75%). Repeatability and reproducibility were adequate, varying from 1.6 to 14%, except for estrone which reproducibility was 28% when the derivatization-GC-MS method was applied. Limits of detection calculated ranged from 2.5 to 27.5 ng/l with differences between both methods from 1.1 (estrone) to 10.4 (bisphenol A) times. Both methods were successfully applied to the analysis of the target compounds in sewage treatment plant influents and effluents. Traces of bisphenol A, 4-tert-octylphenol, estrone and 17beta-estradiol were detected at concentration levels ranging from 13.3 to 1105.2 ng/l.

Determination of traces of five antifouling agents in water by gas chromatography with positive/negative chemical ionisation and tandem mass spectrometric detection.

A highly selective and sensitive gas chromatography-mass spectrometry methodology has been developed for the determination of five antifouling compounds, currently licensed for use in marine antifouling paints. The procedure uses an ion trap mass spectrometer provided with an external ion source that allows the combined use, in the same analysis, of positive (PCI) and negative (NCI) chemical ionisation and tandem mass spectrometric fragmentation (MS-MS). Ionisation and fragmentation processes were optimised individually for each compound, thus, permitting maximum sensitivity and selectivity to be obtained. A complete validation study, including those aspects that affect both correct quantification and unequivocal confirmation, demonstrated the good performance of the proposed method. Detection limits obtained were lower than 0.005 microg l(-1), except for Irgarol 1051 (0.050 microg l(-1)). The method was applied to real seawater samples from different

Combined toxicity effects of MTBE and pesticides measured with Vibrio fischeri and Daphnia magna bioassays.

Methyl-tert-butyl ether (MTBE), a fuel oxygenate that is added to gasoline, commonly contaminates aquatic systems, many of which are already contaminated with pesticides. The toxic effects (EC(50) value) of several pure pesticides (Diuron, Linuron, Dichlofluanid, Sea nine, Irgarol and tributyltin (TBT)) were measured and compared with the EC(50) value of the pesticide mixed with MTBE, using the Vibrio fischeri and Daphnia magna acute toxicity assays. The interaction between chemicals was evaluated in terms of the effects of mixing on the EC(50) value (i.e. the concentration (mg/L) of a compound or mixture that is required to produce a 50% change in a toxic response parameter) and the time required to generate the toxic response. Presence of MTBE enhanced the EC(50) value of several pesticides (Diuron, Dichlofluanid, TBT and Linuron) and/or the toxic response manifested more rapidly than with pure pesticides. Toxicity enhancements were quite substantial in many cases. For example, the presence of MTBE increased the toxicity of Diuron by more than 50% when tested with the V. fischeri assay (5, 15 and 30 min exposure). Also, the toxic response manifested itself within 5 min whereas without the MTBE the same response arose in 30 min. Presence of MTBE increased the toxicity of Dichlofluanid by 30% when measured with the D. magna assay. Toxicities of only two pesticides (Sea nine and Irgarol) were not raised by the presence of MTBE.