Determination of Chlormequat in Fruit Samples by Liquid Chromatography-Electrospray-Mass Spectrometry/Mass Spectrometry

An ion-pair liquid chromatography-mass spectrometry/mass spectrometry method was developed for the determination of chlormequat in fruit samples. A solid-phase extraction cleanup procedure with C18 cartridges was used. Sample preparation was simple and the achieved detection limit (0.03 mg/kg) and quantitation limit (0.08 mg/kg) were below the maximum residue levels legislated by the European Union. The chromatographic separation was performed by using a C8 column and heptafluorobutyric acid as ion pair reagent. The detection was conducted with an electrospray source and an ion trap as a mass analyzer. The reproducibility of the method gave good run-to-run (8–9%) and day-to-day (9–13%) precision values, and its applicability to the determination of chlormequat in pears and grapes, purées, and pear, apple, and grape juices was demonstrated.

Metabolomic analysis of the effects of cadmium and copper treatment in Oryza sativa L. using untargeted liquid chromatography coupled to high resolution mass spectrometry and all-ion fragmentation

While the knowledge of plant metabolomes has increased in the last few years, their response to the presence of toxicants is still poorly understood. Here, we analyse the metabolomic changes in Japanese rice (Oryza sativa var. Japonica) upon exposure to heavy metals (Cd(ii) and Cu(ii)) in concentrations from 10 to 1000 μM. After harvesting, rice metabolites were extracted from aerial parts of the plants and analysed by HPLC (HILIC TSK gel amide-80 column) coupled to a mass spectrometer quadrupole-Orbitrap (Q-Exactive). Full scan and all ion fragmentation (AIF) mass spectrometry modes were used during the analysis. The proposed untargeted metabolomics data analysis strategy is based on the application of the multivariate curve resolution alternating least squares (MCR-ALS) method for feature detection, allowing the simultaneous resolution of pure chromatographic profiles and mass spectra of all metabolites present in the analysed rice extracts. All-ion fragmentation data were used to confirm the identification of MCR-ALS resolved metabolites. A total of 112 metabolites were detected, and 97 of them were subsequently identified and confirmed. Pathway analysis of the observed metabolic changes suggested an underlying similarity of the responses of the plant to Cd(ii) and Cu(ii), although the former treatment appeared to be the more severe of the two. In both cases, secondary metabolism and amino acid-, purine-, carbon- and glycerolipid-metabolism pathways were affected, in a pattern consistent with reduction in plant growth and/or photosynthetic capacity and with induction of defence mechanisms to reduce cell damage.

Transcriptomic and metabolomic profiling of ionic liquid stimuli unveils enhanced secondary metabolism in Aspergillus nidulans

BACKGROUND

The inherent potential of filamentous fungi, especially of Ascomycota, for producing diverse bioactive metabolites remains largely silent under standard laboratory culture conditions. Innumerable strategies have been described to trigger their production, one of the simplest being manipulation of the growth media composition. Supplementing media with ionic liquids surprisingly enhanced the diversity of extracellular metabolites generated by penicillia. This finding led us to evaluate the impact of ionic liquids' stimuli on the fungal metabolism in Aspergillus nidulans and how it reflects on the biosynthesis of secondary metabolites (SMs).

RESULTS

Whole transcriptional profiling showed that exposure to 0.7 M cholinium chloride or 1-ethyl-3-methylimidazolium chloride dramatically affected expression of genes encoding both primary and secondary metabolism. Both ionic liquids apparently induced stress responses and detoxification mechanisms but response profiles to each stimulus were unique. Primary metabolism was up-regulated by choline, but down-regulated by 1-ethyl-3-methylimidazolium chloride; both stimulated production of acetyl-CoA (key precursor to numerous SMs) and non proteinogenic amino acids (building blocks of bioactive classes of SMs). In total, twenty one of the sixty six described backbone genes underwent up-regulation. Accordingly, differential analysis of the fungal metabolome showed that supplementing growth media with ionic liquids resulted in ca. 40 differentially accumulated ion masses compared to control conditions. In particular, it stimulated production of monodictyphenone and orsellinic acid, otherwise cryptic. Expression levels of genes encoding corresponding polyketide biosynthetic enzymes (i.e. backbone genes) increased compared to control conditions. The corresponding metabolite extracts showed increased cell polarity modulation potential in an ex vivo whole tissue assay (The lial Live Targeted Epithelia; theLiTE™).

CONCLUSIONS

Ionic liquids, a diverse class of chemicals composed solely of ions, can provide an unexpected means to further resolve the diversity of natural compounds, guiding discovery of fungal metabolites with clinical potential.

Wide-range screening of psychoactive substances by FIA-HRMS: identification strategies

Recreational drugs (illicit drugs, human and veterinary medicines, legal highs, etc.) often contain lacing agents and adulterants which are not related to the main active ingredient. Serious side effects and even the death of the consumer have been related to the consumption of mixtures of psychoactive substances and/or adulterants, so it is important to know the actual composition of recreational drugs. In this work, a method based on flow injection analysis (FIA) coupled with high-resolution mass spectrometry (HRMS) is proposed for the fast identification of psychoactive substances in recreational drugs and legal highs. The FIA and HRMS working conditions were optimized in order to detect a wide range of psychoactive compounds. As most of the psychoactive substances are acid-base compounds, methanol-0.1 % aqueous formic acid (1:1 v/v) as a carrier solvent and electrospray in both positive ion mode and negative ion mode were used. Two data acquisition modes, full scan at high mass resolution (HRMS) and data-dependent tandem mass spectrometry (ddMS/HRMS) with a quadrupole-Orbitrap mass analyzer were used, resulting in sufficient selectivity for identification of the components of the samples. A custom-made database containing over 450 substances, including psychoactive compounds and common adulterants, was built to perform a high-throughput target and suspect screening. Moreover, online accurate mass databases and mass fragmenter software were used to identify unknowns. Some examples, selected among the analyzed samples of recreational drugs and legal highs using the FIA-HRMS(ddMS/HRMS) method developed, are discussed to illustrate the screening strategy used in this study. The results showed that many of the analyzed samples were adulterated, and in some cases the sample composition did not match that of the supposed marketed substance.

New branches in the degradation pathway of monochlorocatechols by Aspergillus nidulans: a metabolomics analysis

A collective view of the degradation of monochlorocatechols in fungi is yet to be attained, though these compounds are recognised as key degradation intermediates of numerous chlorinated aromatic hydrocarbons, including monochlorophenols. In the present contribution we have analysed the degradation pathways of monochlorophenols in Aspergillus nidulans using essentially metabolomics. Degradation intermediates herein identified included those commonly reported (e.g. 3-chloro-cis,cis-muconate) but also compounds never reported before in fungi revealing for 4-chlorocatechol and for 3-chlorocatechol unknown degradation paths yielding 3-chlorodienelactone and catechol, respectively. A different 3-chlorocatechol degradation path led to accumulation of 2-chloromuconates (a potential dead-end), notwithstanding preliminary evidence of chloromuconolactones and protoanemonin simultaneous formation. In addition, some transformation intermediates, of which sulfate conjugates of mono-chlorophenols/chlorocatechols were the most common, were also identified. This study provides critical information for understanding the role of fungi in the degradation of chlorinated aromatic hydrocarbons; furthering their utility in the development of innovative bioremediation strategies.

Investigating Aspergillus nidulans secretome during colonisation of cork cell walls

Cork, the outer bark of Quercus suber, shows a unique compositional structure, a set of remarkable properties, including high recalcitrance. Cork colonisation by Ascomycota remains largely overlooked. Herein, Aspergillus nidulans secretome on cork was analysed (2DE). Proteomic data were further complemented by microscopic (SEM) and spectroscopic (ATR-FTIR) evaluation of the colonised substrate and by targeted analysis of lignin degradation compounds (UPLC-HRMS). Data showed that the fungus formed an intricate network of hyphae around the cork cell walls, which enabled polysaccharides and lignin superficial degradation, but probably not of suberin. The degradation of polysaccharides was suggested by the identification of few polysaccharide degrading enzymes (β-glucosidases and endo-1,5-α-l-arabinosidase). Lignin degradation, which likely evolved throughout a Fenton-like mechanism relying on the activity of alcohol oxidases, was supported by the identification of small aromatic compounds (e.g. cinnamic acid and veratrylaldehyde) and of several putative high molecular weight lignin degradation products. In addition, cork recalcitrance was corroborated by the identification of several protein species which are associated with autolysis. Finally, stringent comparative proteomics revealed that A. nidulans colonisation of cork and wood share a common set of enzymatic mechanisms. However the higher polysaccharide accessibility in cork might explain the increase of β-glucosidase in cork secretome.

BIOLOGICAL SIGNIFICANCE

Cork degradation by fungi remains largely overlook. Herein we aimed at understanding how A. nidulans colonise cork cell walls and how this relates to wood colonisation. To address this, the protein species consistently present in the secretome were analysed, as well as major alterations occurring in the substrate, including lignin degradation compounds being released. The obtained data demonstrate that this fungus has superficially attacked the cork cell walls apparently by using both enzymatic and Fenton-like reactions. Only a few polysaccharide degrading enzymes could be detected in the secretome which was dominated by protein species associated with autolysis. Lignin degradation was corroborated by the identification of some degradation products, but the suberin barrier in the cell wall remained virtually intact. Comparative proteomics revealed that cork and wood colonisation share a common set of enzymatic mechanisms.

Polychlorinated dibenzo-p-dioxins, dibenzofurans, biphenyls, paraffins and polybrominated diphenyl ethers in marine fish species from Ebro River Delta (Spain)

The results of a surveillance programme on the determination of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and short chain chlorinated paraffins (SCCPs) in marine fish and shellfish species which are fished, commercialised and consumed in the Ebro River Delta area (NE, Spain) are presented. The study included the analysis of five marine fish species (sardine, gilthead sea bream, conger, eel and flounder) and three shellfish species (murex, carpet shell and mussel) collected in 2012 in five fishing harbours near to this area. WHO-TEQ concentrations for PCDD/Fs and dioxin like PCBs (dl-PCBs) ranged from 0.03 to 0.31 pg WHO-TEQ2005PCDD/Fg(-1)wetweight (ww) and from 0.02 to 3.15 pg WHO-TEQ2005PCBg(-1)ww, respectively. All levels were below the maximum concentrations established by the EU Regulation. The PCBs and PCDD/Fs accumulation pattern found in the samples analysed showed a distribution typically reported for marine samples. For marker PCBs and PBDEs, concentration levels ranging from 929 to 57494 pg g(-1)ww and from 36.2 to 827 pg g(-1)ww were obtained, respectively, meanwhile for SCCPs levels were between 3.1 and 141 ng g(-1)ww. Finally, the trends in the levels of PCDD/F and dl-PCBs found from 2006 to 2012 in fish and shellfish species were studied. A slight decrease of PCDD/F and dl-PCB concentrations was found since 2006.

Direct analysis in real time high-resolution mass spectrometry for high-throughput analysis of antiparasitic veterinary drugs in feed and food

RATIONALE

Direct analysis in real time (DART) is a novel ionization technique that has been demonstrated in numerous applications as a useful tool for fast and convenient mass spectrometry (MS)-based analysis of complex samples. In this study, the feasibility of DART ionization coupled to a high-resolution mass spectrometer utilizing an orbitrap mass analyzer (orbitrap MS) for high-throughput analysis of antiparasitic veterinary drugs was explored.

METHODS

To obtain the best DART-orbitrap MS performance, stepwise optimization of instrumental parameter settings, such as ionization gas temperature and mass resolving power, was performed. The optimized method was applied to feed and bovine milk samples previously extracted following a QuEChERS-like strategy.

RESULTS

Most antiparasitic drugs could be analyzed following the described method. Positive DART ionization provided the protonated molecules [M+H](+); in negative DART ion mode, deprotonated molecules [M-H](-) were observed. As an exception, polyether ionophores could be observed as the sodiated adducts [M+Na](+). Samples of milk and feed were extracted using a modified QuEChERS method for the determination of benzimidazoles and coccidiostats respectively and quantification was carried out by matrix-matched calibration curves.

CONCLUSIONS

The combination of an analysis time of less than 1 min per sample and the possibility to acquire accurate masses under high mass resolving power (HR) makes the DART-HRMS technique an effective tool for rapid qualitative screening of antiparasitic veterinary drugs. Additionally, the results obtained in this study demonstrated the feasibility of this approach to quantify target analytes at levels down to 1 µg kg(-1) for benzimidazolic compounds in milk and 0.25 mg kg(-1) for coccidiostats in chicken feed.

New chlorinated amphetamine-type-stimulants disinfection-by-products formed during drinking water treatment

Previous studies have demonstrated high removal rates of amphetamine-type-stimulants (ATSs) through conventional drinking water treatments; however the behaviour of these compounds through disinfection steps and their transformation into disinfection-by-products (DBPs) is still unknown. In this work, for the first time, the reactivity of some ATSs such as amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA) with chlorine has been investigated under simulated and real drinking water treatment conditions in order to evaluate their ability to give rise to transformation products. Two new DBPs from these illicit drugs have been found. A common chlorinated-by-product (3-chlorobenzo)-1,3-dioxole, was identified for both MDA and MDEA while for MDMA, 3-chlorocatechol was found. The presence of these DBPs in water samples collected through drinking water treatment was studied in order to evaluate their formation under real conditions. Both compounds were generated through treatment from raw river water samples containing ATSs at concentration levels ranging from 1 to 15 ng/L for MDA and from 2.3 to 78 ng/L for MDMA. One of them, (3-chlorobenzo)-1,3-dioxole, found after the first chlorination step, was eliminated after ozone and GAC treatment while the MDMA DBP mainly generated after the postchlorination step, showed to be recalcitrant and it was found in final treated waters at concentrations ranging from 0.5 to 5.8 ng/L.

Degradation pathway of pentachlorophenol by Mucor plumbeus involves phase II conjugation and oxidation-reduction reactions

Environmental pollution by pentachlorophenol (PCP) is a critical concern worldwide and fungal bioremediation constitutes an elegant and environment-friendly solution. Mucorales from the Zygomycota phylum are often observed to be competitive in field conditions and Mucor plumbeus, in particular, can efficiently deplete PCP from media. The pathway for PCP degradation used by this fungus has not been investigated. In this study, PCP-derived metabolites were identified by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry, including tetra- and tri-chlorohydroquinones and phase II-conjugated metabolites. Amongst the latter are the previously reported glucose, sulfate and ribose conjugates, and identified for the first time in fungi sulfate-glucose conjugates. A PCP transformation pathway for M. plumbeus is proposed, which excludes the involvement of cytochrome P-450 and extracellular ligninolytic enzymes.

Preventing false negatives with high-resolution mass spectrometry: the benzophenone case

Benzophenone (BP) is one of the many contaminants reported as present in foodstuffs due to its migration from food packaging materials. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is acknowledged in the literature as the method of choice for this analysis. However, cases have been reported where the use of this methodology was insufficient to unambiguously confirm the presence of a contaminant. In previous work performed by the authors, the unequivocal identification of BP in packaged foods was not possible even when monitoring two m/z transitions (precursor ion - product ion), since ion ratio errors higher than 20% were obtained. In order to overcome this analytical problem a fast, sensitive and selective liquid chromatography/high-resolution mass spectrometry (LC/HRMS) methodology has been developed and applied to the analysis of BP in packaged foods. A direct comparison between LC/HRMS and LC/MS/MS data indicated better selectivity when working with LC/HRMS at a resolving power of 50,000 FWHM (full width at half maximum) than when monitoring two m/z transitions by LC/MS/MS. The resolving power used enabled the detection and identification of Harman as the compound impeding the confirmation of BP by LC-MS/MS. Similar quantitative results were obtained by an Orbitrap mass analyser (Exactive™) and a triple quadrupole mass analyser (TSQ Quantum Ultra AM™).

Fast liquid chromatography-tandem mass spectrometry for the analysis of bisphenol A-diglycidyl ether, bisphenol F-diglycidyl ether and their derivatives in canned food and beverages

In this work a fast liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method using a C18 Fused Core™ column, was developed for the simultaneous analysis of bisphenol A diglycidyl ether (BADGE), bisphenol A (2,3-dihydroxypropyl) glycidyl ether (BADGE·H(2)O), bisphenol A bis(2,3-dihydroxypropyl) ether (BADGE·2H(2)O), bisphenol A (3-chloro-2-hydroxypropyl) glycidyl ether (BADGE·HCl), bisphenol A bis(3-chloro-2-hydroxypropyl) ether (BADGE·2HCl) and bisphenol A (3-chloro-2-hydroxypropyl)(2,3-dihydroxypropyl ether) (BADGE·HCl·H(2)O) and bisphenol F diglycidyl ether (BFDGE), bisphenol F bis(2,3-dihydroxypropyl) ether (BFDGE·2H(2)O), bisphenol F bis(3-chloro-2-hydroxypropyl) ether (BFDGE·2HCl). The LC method was coupled with a triple quadrupole mass spectrometer, using an ESI source in positive mode and using the [M+NH(4)](+) adduct as precursor ion for tandem mass spectrometry experiments. The method developed was applied to the determination of these compounds in canned soft drinks and canned food. OASIS HLB solid phase extraction (SPE) cartridges were used for the analysis of soft drinks, while solid canned food was extracted with ethyl acetate. Method limits of quantitation ranged from 0.13 μgL(-1) to 1.6 μgL(-1) in soft drinks and 1.0 μgkg(-1) to 4.0 μgkg(-1) in food samples. BADGE·2H(2)O was detected in all the analyzed samples, while other BADGEs such as BADGE·H(2)O, BADGE·HCl·H(2)O, BADGE·HCl and BADGE·2HCl were also detected in canned foods.

Hydrophilic interaction liquid chromatography/tandem mass spectrometry for the analysis of diallyldimethylammonium chloride in water

We report a selective, sensitive and fast liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of diallyldimethylammonium chloride (DADMAC) in water. Hydrophilic interaction liquid chromatography (HILIC) was used to avoid ion-pairing reagents, which are generally employed to retain cationic compounds. The complementary information obtained in a triple quadrupole mass spectrometer and in an ion trap Orbitrap has been used to study the fragmentation of the DADMAC cation [M](+) and for the correct assignment of the products ions. The HILIC/MS/MS method developed, using electrospray ionization in positive ion mode and selected reaction monitoring (SRM) acquisition mode, led to a reliable determination and confirmation of the DADMAC cation in water samples down to 50 ng L(-1). The low detection limit achieved, in combination with the absence of matrix effects, allowed the direct analysis of samples without any pretreatment, preconcentration or clean-up step. DADMAC was determined in samples collected in a drinking water treatment plant (DWTP) in Barcelona (Spain) and it was found in the influent at the µg L(-1) level.

Occurrence and removal of pharmaceuticals and hormones through drinking water treatment

The occurrence of fifty-five pharmaceuticals, hormones and metabolites in raw waters used for drinking water production and their removal through a drinking water treatment were studied. Thirty-five out of fifty-five drugs were detected in the raw water at the facility intake with concentrations up to 1200 ng/L. The behavior of the compounds was studied at each step: prechlorination, coagulation, sand filtration, ozonation, granular activated carbon filtration and post-chlorination; showing that the complete treatment accounted for the complete removal of all the compounds detected in raw waters except for five of them. Phenytoin, atenolol and hydrochlorothiazide were the three pharmaceuticals most frequently found in finished waters at concentrations about 10 ng/L. Sotalol and carbamazepine epoxide were found in less than a half of the samples at lower concentrations, above 2 ng/L. However despite their persistence, the removals of these five pharmaceuticals were higher than 95%.

Multiple-stage mass spectrometry analysis of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether and their derivatives

The fragmentation of bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE) and their derivatives was studied by electrospray ionization tandem mass spectrometry. Multiple-stage mass spectrometry and accurate mass measurements were combined to establish the fragmentation pathways. BADGEs and BFDGEs tend to form ammonium adducts under electrospray conditions which fragmented easily. The fragmentation of [M+NH(4)](+) for BADGEs started with the cleavage of the phenyl-alkyl bond, which was followed by the α-cleavage of the ether group to generate the characteristic product ions at m/z 135, [C(9)H(11)O](+), and m/z 107, [C(7)H(7)O](+). The fragmentation of the BFDGE isomer mixtures was studied by on-line reversed-phase liquid chromatography coupled to multiple-stage mass spectrometry (LC/MS(n)). Information obtained from product ion spectra for each BFDGE isomer and its comparison with the fragmentation pathway of BADGE allowed each isomer and the chromatographic elution order to be identified.

Occurrence of furan in coffee from Spanish market: Contribution of brewing and roasting

In this work, we evaluated the occurrence of furan in brews obtained from regular, decaffeinated, and instant coffee and commercial packed capsules. For this purpose, a previously developed automated headspace solid-phase microextraction method coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used. Initially, the influence of HS-SPME conditions on furan formation was evaluated. In addition, the effect of roasting conditions (temperature and time) used for coffee beans on furan formation was also studied. We found that low temperature and long roasting time (140°C and 20min) decreases the final furan content. Furan concentrations in regular ground coffee brews from an espresso coffee machine were higher (43-146ng/ml) than those obtained from a home drip coffee maker (20 and 78ng/ml), while decaffeinated coffee brews from a home drip coffee maker (14-65ng/ml) showed a furan concentration similar to that obtained from regular coffee. Relatively low concentrations of this compound (12-35ng/ml) were found in instant coffee brews, while commercial packed coffee capsules showed the highest concentrations (117-244ng/ml). Finally, the daily intake of furan through coffee consumption in Barcelona (Spain) (0.03-0.38μg/kg of body weight) was estimated.

Recent advances in mass spectrometry analysis of phenolic endocrine disruptors and related compounds

This article reviews recent literature on current methodologies based on chromatography coupled to mass spectrometry to analyze phenolic compounds with endocrine-disrupting capabilities. For this review we chose alkylphenol ethoxylates, bisphenol A, bisphenol F, and their degradation products and halogenated derivatives, which are considered important environmental contaminants. Additionally, some related compounds such as bisphenol diglycidylethers were included. Growing attention has been paid to the mass spectrometric characterization of these compounds and the instrumentation and strategies used for their quantification and confirmation. The current use of gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) methodologies with different mass spectrometers and ionization and monitoring modes is discussed. Practical aspects with regards to the use of these analytical techniques, such as derivatizing reagents in GC-MS, ion suppression in LC-MS, and the most problematic aspects of quantification, are included in the discussion.

Biomagnification of anthropogenic and naturally-produced organobrominated compounds in a marine food web from Sydney Harbour, Australia

Polybrominated diphenyl ethers (PBDEs) and naturally-produced organobrominated compounds, such as methoxylated PBDEs (MeO-PBDEs), have been scarcely studied in the Southern Hemisphere. Yet, sources of the latter group of compounds were found in Southern regions, specifically in Australia. The environmental distribution and biomagnification potential of organobrominated compounds were therefore investigated in a representative aquatic food chain (invertebrates and fish) from the Sydney Harbour, Australia. Mean PBDE concentrations ranged from 6.4ng/g lipid weight (lw) in squid to 115 ng/g lw in flounder. BDE 47 was the dominant congener, followed by BDE 100. Mean levels of MeO-PBDEs (sum of congeners 2'-MeO-BDE 68 and 6-MeO-BDE 47) were as high as 110 ng/g lw in tailor, with a slight dominance of 2'-MeO-BDE 68. Polybrominated hexahydroxanthene derivates (PBHDs), another class of naturally-produced compounds, were found at variable concentrations and ranged from 4.7 ng/g lw in fanbelly and 146ng/g lw in tailor. The tribrominated PBHD isomer dominated in the samples, except for luderick and squid. The lower levels of PBDEs found in luderick from the harbour compared to those obtained from the upper Parramatta River indicated a terrestrial (anthropogenic) origin of PBDEs, while the higher levels of MeO-PBDEs and PBHDs in the samples from the harbour confirmed the marine (natural) origin of these compounds. The highest trophic magnification factor (TMF) was found for sum PBDEs (3.9), while TMFs for sum MeO-PBDEs and sum PBHDs were 2.9 and 3.4, respectively. This suggests that biomagnification occurs in the studied aquatic food chain for anthropogenic brominated compounds, but also for the naturally-produced organobromines.

Stimulatory drugs of abuse in surface waters and their removal in a conventional drinking water treatment plant

The presence of psychoactive stimulatory drugs in raw waters used for drinking water production and in finished drinking water was evaluated in a Spanish drinking water treatment plant (DWTP). Contamination of the river basin which provides raw water to this DWTP was also studied. In surface waters, illicit drugs such as cocaine, benzoylecgonine (cocaine metabolite), amphetamine, methamphetamine, MDMA (ecstasy), and MDA were detected at mean concentrations ranging from 4 to 350 ng/L. Nicotine, caffeine, and their metabolites were also found at the microg/L level. The elimination of these compounds during drinking water treatment was investigated in a real waterworks. Amphetamine-type stimulants (except MDMA) were completely removed during prechlorination, flocculation, and sand filtration steps, yielding concentrations lowerthan their limits of detection (LODs). Further, ozone treatment was shown to be effective in partially eliminating caffeine (76%), while subsequent granulated activated carbon (GAC) filtration removed cocaine (100%), MDMA(88%), benzoylecgonine (72%), and cotinine (63%). Postchlorination achieved the complete elimination of cocaine and nicotine and only one parent compound (caffeine) and two metabolites (cotinine and benzoylecgonine) persisted throughout treatment although reductions of 90% for caffeine and benzoylecgonine and 74% for cotinine were obtained.

Determination of Viable Yeast Cells by Gravitational Field-Flow Fractionation with Fluorescence Detection

Vinification processing is largely related to yeast performance and depends on the initial cell viability. To optimize the quality of wine fermentation, control of the yeast quality is mandatory. The present paper describes a new method using gravitational field flow fractionation (GrFFF) with fluorescence detection for the determination of yeast cell viability before the fermentation process. A GrFFF calibration procedure was developed using commercial yeast to prepare standards of viable cells and propidium iodide (PI) as fluorescent probe for nonviable cells. The suitability of the new method was tested with several commercial yeast strains with a g/L content ranging from 1 to 3. The validation of the method was performed by comparing GrFFF viability values with those obtained using Coulter counter and flow cytometry techniques.

Occurrence of psychoactive stimulatory drugs in wastewaters in north-eastern Spain

The occurrence of several psychoactive drugs in water resources from north-eastern Spain (NE-Spain) has been evaluated. The drugs were analyzed using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-ESI-MS/MS) after enrichment by solid-phase extraction (SPE). Most of the studied controlled drugs (8 out of 11) were found in both influent and effluent samples from several wastewater treatment plants. Cocaine and its metabolite were detected in wastewaters at concentrations ranging from 4 ng/L to 4.7 mug/L and from 9 ng/L to 7.5 mug/L respectively while concentrations of amphetamine type stimulatory drugs ranged from 2 to 688 ng/L. Removal percentages were estimated by sampling eight WWTPs (n=4). Cocaine and benzoylecgonine removal percentages were higher than 88% while those of amphetamine type stimulants varied ranging from 40% to more than 99%. Daily variability was also evaluated by performing a sequential survey, which revealed important fluctuations in the concentrations of nicotine, paraxanthine, amphetamine and ecstasy during the week. From the total concentrations found in wastewater influents estimations of the cocaine and ecstasy consumption were performed. For cocaine the results were approximately 14 doses per 1000 inhabitants (15-64 years old) per day and for ecstasy, approximately 4 doses per 1000 young adults (15-34 years old) per day for ecstasy.

Liquid chromatography coupled to tandem mass spectrometry for the analysis of acrylamide in typical Spanish products

This paper describes the use of liquid chromatography coupled to tandem mass spectrometry for the determination of acrylamide in several typical foods produced and consumed in Spain. Christmas sweets, olives, traditionally made potato crisps, pastry products, sweet fritters ("churros") and one of Spain's most famous dishes, Spanish omelette, were selected. Using the mass spectra information provided by an ion trap analyzer in combination with the accurate mass measurements from time-of-flight (TOF) spectrometry a co-extractive interference present in some potato products was identified as valine. A porous graphitic carbon column, which enabled the co-extractive and acrylamide to be separated, and ion trap or triple quadrupole analyzers, depending on the acrylamide concentration, were used to determine this genotoxic compound in foodstuffs. The highest values were found in potato products, sweet fritters, Christmas sweets and pastry products, with values ranging between 70 and 2000 microg/g. Spanish omelette presented relatively low levels, similar to those obtained for dried fruits.

Occurrence of polychlorinated naphthalenes, polychlorinated biphenyls and short-chain chlorinated paraffins in marine sediments from Barcelona (Spain)

Polychlorinated naphthalenes (PCNs), short-chain chlorinated paraffins (SCCPs) and polychlorinated biphenyls (PCBs) were analysed in marine sediment samples collected from the coastal area of Barcelona (Spain) and near of a submarine emissary coming from a waste water treatment plant located at the mouth of the Besòs River (Barcelona). An integrated sample treatment based on Soxhlet extraction followed by a simple clean-up with Florisil and graphitized carbon cartridge was employed. Gas chromatography coupled to ion-trap tandem mass spectrometry (GC-MS/MS) and gas chromatography-mass spectrometry in electron capture negative ionization mode, were used for PCN and SCCP determinations, respectively, while for PCB analysis gas chromatography with electron capture detection (GC-ECD) was used. The method developed provided low limits of detection (0.001-0.003 ng g(-1) dry weight (dw) for PCNs, 1.8 ng g(-1) for SCCPs and 0.006-0.014 ng g(-1)dw for PCBs) and good run-to-run precisions (lower than RSD 8%) for the analysis of sediment samples. Concentration levels ranging from 0.17 to 3.27 ng g(-1)dw for PCNs, between 0.21 and 1.17 microg g(-1)dw for SCCPs, and from 2.33 to 44.00 ng g(-1) (dw) for PCBs, were found in the coastal sediments, while for samples collected near to the submarine emissary higher levels (from 2.02 to 6.56 ng g(-1)dw for PCNs, between 1.25 and 2.09 microg g(-1)dw for SCCPs and from 22.34 to 37.74 ng g(-1)dw for PCBs) were obtained. The results obtained provide new data about the occurrence of PCN and SCCP in the coastal area of Barcelona.

Liquid chromatography-tandem mass spectrometry analysis of 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5-b]pyridine in cooked meats

Several cooked meats such as beef (fried, coated-fried), pork (fried, coated-fried), and chicken (fried, griddled, coated-fried, roasted) were analyzed for the heterocyclic amine 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5- b]pyridine (4'-OH-PhIP) not commonly determined in food and 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP). The highest content of 4'-OH-PhIP was found in fried and griddled chicken breast, the concentration being 43.7 and 13.4 ng/g, respectively, whereas the corresponding PhIP concentrations were 19.2 and 5.8 ng/g. The estimated concentration of both pyridines in fried pork loin, in fried pork sausages, and in coated-fried chicken was below 2.5 ng/g. In the rest of the samples, 4'-OH-PhIP was not detected. The analyses were performed by solid-phase extraction and LC-MS/MS. The fragmentation of 4'-OH-PhIP in an ion trap mass analyzer was studied in order to provide information for the identification of 4'-OH-PhIP. Additionally, the effect of red wine marinades on the formation of 4'-OH-PhIP in fried chicken was examined, finding a notable reduction (69%) in the amine's occurrence.

Field amplified sample injection–capillary electrophoresis–tandem mass spectrometry for the analysis of acrylamide in foodstuffs

This paper shows the applicability of capillary electrophoresis (CE) coupled to mass spectrometry (MS) for the analysis of acrylamide (AA) in foodstuffs. In order to obtain an ionisable compound amenable to be analysed by CE, acrylamide was derivatised with 2-mercaptobenzoic acid. Spectra in positive and negative modes were studied in order to select the best ionisation mode and multistep tandem mass spectrometry was used to obtain structural information. Maximum signal was observed when negative mode was used and MS/MS and MS3 were selected for quantitation and confirmation, respectively. For the separation, a fused-silica capillary of 80 cm and 50 microm I.D. and 35 mM ammonium formate/ammonia solution at pH 10 as running electrolyte were used. The applicability of field amplified sample injection (FASI) in reversed polarity was evaluated in order to decrease detection limits. The developed FASI-CE-MS/MS method provided a detection limit of 8 ng g(-1) and good linearity (r=0.999) and precision (day-to-day lower than 15%). The method has been applied to the analysis of different representative food products and the results were compared with those obtained by LC-MS/MS.

CEC separation of heterocyclic amines using methacrylate monolithic columns

Two methacrylate-based monolithic columns, one with a negatively charged group (sulfonic group) and another with a new monomer N,N-dimethylamino ethyl acrylate (DMAEA), were prepared and tested for the separation of basic compounds by CEC. This new monolithic stationary phase was prepared by the in situ polymerization of DMAEA with butyl methacrylate and ethylene dimethacrylate, using a ternary porogenic solvent consisting of water, 1-propanol and 1,4-butanediol. The performance of this column was evaluated by means of the analysis of a family of heterocyclic amines. Separation conditions such as pH, amount of organic modifier, ionic strength and elution mode (normal or counterdirectional flow) were studied. At the optimal running electrolyte composition, and using the counterdirectional mode, symmetrical electrochromatographic peaks were obtained, with the number of theoretical plates up to 30,000 and a good resolution between closely related peaks. The 2-acrylamido-2-methyl-1-propane-sulfonic acid column was used for CEC-MS, taking advantage of the compatibility of its elution mode (normal flow) with the MS coupling.

Analysis of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in vegetable oil samples by gas chromatography–ion trap tandem mass spectrometry

Gas chromatography coupled to ion trap tandem mass spectrometry (CG-MS-MS) has been evaluated for the analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in vegetable oil samples containing different concentration levels (0.2-6 pg WHO-TEQ g(-1) for both PCDD/Fs and dl-PCBs) of the 29 toxic congeners of PCDD/F and dioxin-like PCBs. The effect of potential interfering compounds such as polychlorinated naphthalenes (PCNs), polychlorinated biphenyls (PCBs) and polychlorinated diphenylethers (PCDEs) on the quantification of mono-ortho PCBs has been investigated. In addition, the influence of the clean-up procedure on the final determination by CG-MS-MS was studied, showing that the quality of the results depends to a great extent on this analytical step. Quality parameters have been established and good precisions (CV: 3-19%) and low limits of detection for PCDD/Fs (0.04-0.20 pg g(-1) oil) and dl-PCBs (0.08-0.64 pg g(-1) oil) were obtained. The method was validated by a comparison of the CG-MS-MS results with those obtained by GC-HRMS.

Ultraperformance Liquid Chromatography−Tandem Mass Spectrometry Analysis of Stimulatory Drugs of Abuse in Wastewater and Surface Waters

Ultraperformance liquid chromatography coupled to electrospray tandem mass spectrometry was used for the rapid and simultaneous analysis of 15 stimulatory drugs in water. Cocaine, amphetamine-related compounds, LSD, ketamine, PCP, fentanyl, and metabolites, among the controlled drugs, and nicotine, caffeine, and their metabolites, among the noncontrolled drugs, were studied. Chromatographic separation was achieved in less than 4.5 min, with improved peak resolution and sensitivity. Identification and quantification of the compounds of interest was performed by selected reaction monitoring, using an electrospray ionization source. Isotope dilution (except for paraxanthine) was used for quantitation. Quality parameters of the method were established, and limits of quantification were obtained for controlled drugs in surface waters from 0.1 to 3.1 ng/L and in wastewaters from 0.2 to 4.0 ng/L. Run-to-run and day-to-day precisions were evaluated in different water matrixes (Milli-Q water, surface water, wastewater). To assess the presence of these drugs in real water samples, the optimized method was applied to the analysis of wastewater and surface river water. The analysis of several samples from wastewater treatment plants in northeast Spain revealed the presence of drugs such as cocaine and amphetamine-related compounds, in both influent and effluent samples. Cocaine metabolite and MDMA (ecstasy) were also found in surface waters while nicotine and caffeine were detected in all the analyzed samples. The results obtained demonstrate that the presence of these drugs in the aquatic media must be considered a matter of environmental concern.

Heterocyclic amines in griddled beef steak analysed using a single extract clean-up procedure

Heterocyclic amines (HAs), which are potent mutagenic and carcinogenic substances, are formed in muscle meats during their cooking under ordinary conditions. In this work, we measured the concentration of 15 HAs in different samples of griddled beef steak, which is one of the most consumed meat items is Spain. Three samples were obtained from different restaurants, and the other sample was cooked under controlled conditions to a well-done degree of doneness. A low-time consuming solid-phase extraction procedure was used to purify the samples, and liquid chromatography-tandem mass spectrometry with an ion trap mass analyzer was used as determination technique. A second well-established purification procedure was used to demonstrate the applicability of the method to the analysis of these kind of samples. 8-MeIQx, 4,8-DiMeIQx, PhIP and the comutagens Harman and Norharman were found in all the samples, at levels ranging from 0.28 to 21.2ngg(-1). AalphaC was found in three samples (0.18-1.41ngg(-1)), whereas Trp-P-1 was detected in two samples (0.35ngg(-1)). MeAalphaC was found in three samples but could only be quantified in one (0.15ngg(-1)). Trp-P-2 and DMIP were also detected in some cases at levels below their limit of quantification. The remaining HAs analyzed were not detected in any of the samples.

Analysis of furan in foods by headspace solid-phase microextraction–gas chromatography–ion trap mass spectrometry

A headspace-solid-phase microextraction (HS-SPME) coupled to gas chromatography-ion trap mass spectrometry (GC-IT-MS) method is proposed for the analysis of furan in different heat-treated carbohydrate-rich food samples. The extraction efficiency of six commercially available fibres was evaluated and it was found that a 75mum carboxen/polydimethylsiloxane coating was the most suitable for the extraction of the furan. Parameters affecting the efficiency of HS-SPME procedure such as extraction temperature and time, ionic strength, headspace and aqueous volume ratio (V(h)/V(w)), desorption temperature and time, were optimized. Quality parameters were established using spiked water and food samples. Linearity ranged between 0.02 and 0.5ngg(-1) and run-to-run and day-to-day precisions for food samples were lower than 6% and 10%, respectively. The limit of detection (LOD) of the method is sample dependent and ranged from 8 to 70pgg(-1), while the limit of quantification is from 30 to 250pgg(-1). Isotope dilution using furan-d(4) is proposed for furan determination providing similar results to those obtained by standard addition with internal standard (US Food and Drug Administration method). The developed HS-SPME-GC-IT-MS method was applied to the analysis of furan in different Spanish food samples from a local market, and concentrations ranging from 0.17 to 2279ngg(-1) were found.

Analysis of 5-hydroxymethylfurfural in foods by gas chromatography–mass spectrometry

A new, simple and selective method for the analysis of 5-hydroxymethylfurfural (HMF) in foods by gas chromatography coupled to mass spectrometry (GC-MS) is proposed. Several derivatising procedures based on the formation of an HMF silylated derivative using different reagents were studied. Among the derivatising reagents examined, N,O-bis-trimethylsilyltrifluoroacetamide (BSTFA) provided the best derivatisation yield. Sample clean-up was also optimised, using either liquid-liquid extraction with dichloromethane or solid-phase extraction (SPE) with several commercially available cartridges, and the best results were obtained using ENV+ cartridges. Quality parameters such as day-to-day and run-to-run precision (RSD<10%), linearity (between 25 and 700 ng g(-1)) and detection limit (6 ng g(-1)) were established. This method was successfully applied to the analysis of HMF content in several Spanish food samples from a local market, such as jam, honey, orange juice and bakery products.

Effect of red wine marinades on the formation of heterocyclic amines in fried chicken breast

Genotoxic heterocyclic amines (HAs) are formed via the Maillard reaction and free radical reaction mechanisms when meat or fish is cooked at usual cooking conditions. In this paper, the effect of the addition of red wine was tested to study if it interferes in HA formation. Fried chicken breast was the food item chosen, and three different red wines, characterized in terms of grape varieties, free amino acids, antioxidant properties, and metallic composition, were used to marinate meat prior to the heating process. Unmarinated samples and samples marinated with an ethanol-water mixture provided reference HA levels. The frying experiments were performed under well-controlled temperature and time conditions. The samples were analyzed for HA content using solid-phase extraction and LC-MS/MS. DMIP, PhIP, MeIQx, 4,8-DiMeIQx, IFP, TMIP, harman, and norharman were identified in fried chicken breast. Red wine marinades were found to reduce the formation of some of the HAs formed. PhIP, with a reduction of up to 88%, was the most minimized amine, although the formation of harman was enhanced.

Ultra-performance liquid chromatography–tandem mass spectrometry for the analysis of heterocyclic amines in food

A new ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) method was developed to perform the determination of 16 mutagenic heterocyclic amines (HAs) in complex food samples in less than 2 min. The UPLC separation was carried out using an Acquity BEH C18 column (50 mm x 2.1 mm i.d., 1.7 microm particle size) that provided high efficiency and resolution in combination with high linear velocities. The UPLC system was coupled to the triple quadrupole Waters Micromass Quattro Premier. This system permits high-speed data acquisition without peak intensity degradation which is required to monitor the narrow chromatographic peaks (1-2 s) of HAs. The determination was performed in selected reaction monitoring (SRM) mode. The quality parameters of the developed method were established, obtaining instrumental LODs lower than 0.23 pg injected and a repeatability at low concentration level lower than 9.1% CV (n = 6). To evaluate the performance of the method in high throughput analysis of complex samples, the UPLC-MS/MS method was applied to the analysis of HAs in two meat extracts.

Analysis of polychlorinated n-alkanes in environmental samples

Polychlorinated n-alkanes (PCAs), also known as chlorinated paraffins (CPs), are highly complex technical mixtures that contain a huge number of structural isomers, theoretically more than 10,000 diastereomers and enantiomers. As a consequence of their persistence, tendency to bioaccumulation, and widespread and unrestricted use, PCAs have been found in aquatic and terrestrial food webs, even in rural and remote areas. Recently, these compounds have been included in regulatory programs of several international organizations, including the US Environmental Protection Agency and the European Union. Consequently, there is a growing demand for reliable methods with which to analyze PCAs in environmental samples. Here, we review current trends and recent developments in the analysis of PCAs in environmental samples such as air, water, sediment, and biota. Practical aspects of sample preparation, chromatographic separation, and detection are covered, with special emphasis placed on analysis of PCAs using gas chromatography-mass spectrometry. The advantages and limitations of these techniques as well as recent improvements in quantification procedures are discussed.

Analysis of odorous trichlorobromophenols in water by in-sample derivatization/solid-phase microextraction GC/MS

The simultaneous determination of several odorous trichlorobromophenols in water has been carried out by an in-sample derivatization headspace solid-phase microextraction method (HS-SPME). The analytical procedure involved their derivatization to methyl ethers with dimethyl sulfate/NaOH and further HS-SPME and gas chromatography-mass spectrometry (GC/MS) determination. Parameters affecting both the derivatization efficiency and headspace SPME procedures, such as the selection of the SPME fiber coating, derivatization-extraction time and temperature, were studied. The commercially available polydimethylsiloxane (PDMS) 100 microm and Carboxen-polydimethylsiloxane-divinylbenzene (CAR-PDMS-DVB) fibers appeared to be the most suitable for the simultaneous determination of these compounds. The precision of the HS-SPME/GC/MS method gave good relative standard deviations (RSDs) run-to-run between 9% and 19% for most of them, except for 2,5-diCl-6-Br-phenol, 2,6-diCl-3-Br-phenol and-2,3,6-triBr-phenol (22%, 25% and 23%, respectively). The method was linear over two orders of magnitude, and detection limits were compound dependent but ranged from 0.22 ng/l to 0.95 ng/l. The results obtained for water samples using the proposed SPME procedure were compared with those found with the EPA 625 method, and good agreement was achieved. Therefore, the in-sample derivatization HS-SPME/GC/MS procedure here proposed is a suitable method for the simultaneous determination of odorous trichlorobromophenols in water.

Analysis of acrylamide in food products by in-line preconcentration capillary zone electrophoresis

Two in-line preconcentration capillary zone electrophoresis (CZE) methods (field amplified sample injection (FASI) and stacking with sample matrix removal (LVSS)) have been evaluated for the analysis of acrylamide (AA) in foodstuffs. To allow the determination of AA by CZE, it was derivatized using 2-mercaptobenzoic acid. For FASI, the optimum conditions were water at pH > or = 10 adjusted with NH3 as sample solvent, 35 s hydrodynamic injection (0.5 psi) of a water plug, 35 s of electrokinetic injection (-10 kV) of the sample, and 6s hydrodynamic injection (0.5 psi) of another water plug to prevent AA removal by EOF. In stacking with sample matrix removal, the reversal time was found to be around 3.3 min. A 40 mM phosphate buffer (pH 8.5) was used as carrier electrolyte for CZE separation in both cases. For both FASI and LVSS methods, linear calibration curves over the range studied (10-1000 microg L(-1) and 25-1000 microg L(-1), respectively), limit of detection (LOD) on standards (1 microg L(-1) for FASI and 7 microg L(-1) for LVSS), limit of detection on samples (3 ng g(-1) for FASI and 20 ng g(-1) for LVSS) and both run-to-run (up to 14% for concentration and 0.8% for time values) and day-to-day precisions (up to 16% and 5% for concentration and time values, respectively) were established. Due to the lower detection limits obtained with the FASI-CZE this method was applied to the analysis of AA in different foodstuffs such as biscuits, cereals, crisp bread, snacks and coffee, and the results were compared with those obtained by LC-MS/MS.

Analysis of acrylamide in food samples by capillary zone electrophoresis

Conditions for the determination of acrylamide (AA) after derivatisation with 2-mercaptobenzoic acid by capillary zone electrophoresis were established. A derivatisation reagent-acrylamide ratio of 35:1 was selected as optimum and the reagent excess was not removed as it did not affect the determination of acrylamide by CZE. The best separation was achieved using a 40 mM phosphate buffer at pH 8.0, working at 25 kV in un-coated fused silica capillaries. Linear calibration curves over the range studied (0.3-100 microg mL(-1)), the limit of detection (0.07 microg mL(-1)), and both run-to-run (RSD values of 5.8 and 2.2% for concentration at low and medium concentration levels, respectively) and day-to-day precisions (up to 11.2 and 6.7% at low and medium concentration levels, respectively) were established. Finally, the applicability of the CZE proposed methodology was demonstrated by analyzing levels of acrylamide present in different foodstuff products such as home made french fries, breakfast cereals and biscuits.