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Analytical and Bioanalytical Chemistry (v.404, #9)

Gregor Jung (Ed.): Fluorescent proteins I. From understanding to design, and : Fluorescent proteins II. Application of fluorescent protein technology by Sapna K. Deo (pp. 2521-2522).

Shu-Lin Zhang: Raman spectroscopy and its application in nanostructures by Jürgen Popp (pp. 2523-2524).

Emerging contaminants in biota by Yolanda Picó; Damià Barceló (pp. 2525-2526).

is Full Professor of Nutrition and Food Science at the University of Valencia since 1998. Her research interests are the development of new analytical methods to determine organic contaminants in food and the environment, identification of unknown compounds by liquid chromatography–mass spectrometry, microextraction separations, and environmental and food safety. She is author of nearly 180 peer-reviewed papers, 140 scientific papers in SCI journals, and 25 book chapters. She is also editor of three books on food and environmental safety. is currently Research Professor of the Scientific Research Council (CSIC) of the Government of Spain at the Institute of Environmental Assessment and Water Research (IDAEA), Barcelona, Spain, and Director of the Catalan Institute for Water Research (ICRA). Since December 2009, he has also been visiting professor at King Saud University, Riyadh, Saudi Arabia. His research interest are water quality assessment and management, fate and behaviour of emerging contaminants in surface waters, wastewaters, groundwater, and biota, and analysis, fate, and risk of nanomaterials in the environment. He has published over 670 original papers and 200 book chapters, and has edited 30 books. In 2007 he was awarded the King Jaime I Prize for the Protection of Nature from Generalitat of Valencia, Spain, for his outstanding scientific work. Since 2011 he has been chairman of the Scientific and Technological Board (STB) of the European Union-Joint Programming Initiative on “Water Challenges for a Changing World”.

Analytical methods for the detection of viruses in food by example of CCL-3 bioagents by E. M. Hartmann; R. U. Halden (pp. 2527-2537).

This critical review presents challenges and strategies in the detection of viral contaminants in food products. Adenovirus, caliciviruses, enteroviruses, and hepatitis A are emerging contaminant viruses. These viruses contaminate a variety of food products, including fruits, vegetables, shellfish, and ready-to-eat processed foods. The diversity of targets and sample matrices presents unique challenges to virus monitoring that have been addressed by a wide array of processing and detection methods. This review covers sample acquisition and handling, virus recovery/concentration, and the determination of targets using molecular biology and mass-spectrometric approaches. The concentration methods discussed include precipitation, antibody-based concentration, and filtration; the detection methods discussed include microscopy, polymerase chain reaction, nucleic acid sequence-based amplification, and mass spectrometry.

Keywords: Norovirus; Hepatitis A; Adenovirus; Enterovirus; Processing; Detection

Challenges encountered in the analysis of phthalate esters in foodstuffs and other biological matrices by Ying Guo; Kurunthachalam Kannan (pp. 2539-2554).

Phthalate esters are ubiquitous environmental pollutants and are recognized as environmental endocrine disruptors because of their potential to elicit reproductive and developmental toxicity. Several phthalate esters have been listed by the US Environmental Protection Agency (EPA) as chemicals of concern. Determination of concentrations of phthalate esters in foodstuffs, typically present at sub to low nanogram-per-gram concentrations (between 0.1 and 100 ng g⁻¹), is essential for assessment of human dietary exposure. However, phthalate esters are commonly present as contaminants in several laboratory products, including organic solvents, that are used in sample preparation and analysis. Therefore, accurate analysis of phthalates in food samples is a challenging task. In this review, we summarize the methods available for the determination of phthalate esters in foodstuffs and report on concentrations of phthalates in foodstuffs and potential sources of contamination by phthalates in the analysis of foodstuffs. We offer suggestions to eliminate and/or reduce background levels of contamination by phthalates in the analysis of food and other biological samples. We also introduce methods that are suitable for trace analysis of phthalates in a variety of liquid and solid food samples, in particular, a liquid–liquid extraction method for removal of lipids from food samples, because these can substantially reduce background levels of phthalates in the analytical procedure.

Keywords: Quality assurance; Pesticides; Endocrine disruptors; Plasticizers; Phthalate; Organic compounds; Foods; Beverages; Human exposure

Analytical methods for selected emerging contaminants in human matrices—a review by Alin C. Dirtu; Nele Van den Eede; Govindan Malarvannan; Alin C. Ionas; Adrian Covaci (pp. 2555-2581).

Emerging contaminants are a broad category of chemicals, previously unknown or unrecognized as being of concern, but which, because of their potential health effects associated with human exposure, are under increasing scrutiny. To accurately measure their levels in biological matrices, specific and sensitive analytical methods have recently been developed. We have reviewed here the methods used for analysis of selected emerging organic contaminants, for example metabolites of organophosphate triesters, metabolites of new phthalates or phthalate substitutes, perchlorate, organic UV filters, and polycyclic siloxanes, in human matrices. Although the use of new techniques and approaches has been emphasized, we also acknowledge methods previously used for other contaminants and adapted for the emerging contaminants listed above. In all cases, chromatography and mass spectrometry were the techniques of choice, because of their selectivity and sensitivity for measurements at ng g⁻¹ levels. Critical issues and challenges have been discussed, together with recommendations for further improvement in particular cases (e.g. metabolites of phthalates or their substitutes). In particular, the use of labeled internal standards, the availability of certified reference materials, and the need for interlaboratory comparison exercises are key aspects of further development of this field of research. Figure Humans are daily exposed to a cocktail of chemicals, including new compounds

Keywords: Emerging contaminants; Analytical methods; Organophosphate triesters; Phthalate substitutes; Perchlorate; UV filters; Polycyclic siloxanes; Metabolites; Human matrices

Beyond nC₆₀: strategies for identification of transformation products of fullerene oxidation in aquatic and biological samples by Benny F. G. Pycke; Tzu-Chiao Chao; Pierre Herckes; Paul Westerhoff; Rolf U. Halden (pp. 2583-2595).

Owing to their exceptional properties and versatility, fullerenes are in widespread use for numerous applications. Increased production and use of fullerenes will inevitably result in accelerated environmental release. However, study of the occurrence, fate, and transport of fullerenes in the environment is complicated because a variety of surface modifications can occur as a result of either intentional functionalization or natural processes. To gain a better understanding of the effect and risk of fullerenes on environmental health, it is necessary to acquire reliable data on the parent compounds and their congeners. Whereas currently established quantification methods generally focus on analysis of unmodified fullerenes, we discuss in this review the occurrence and analysis of oxidized fullerene congeners (i.e., their corresponding epoxides and polyhydroxylated derivatives) in the environment and in biological specimens. We present possible strategies for detection and quantification of parent nanomaterials and their various derivatives.

Keywords: Polyhydroxylated fullerene; Fullerene epoxide; Biota; Bioaccumulation; Mass spectrometry

An overview of UV-absorbing compounds (organic UV filters) in aquatic biota by Pablo Gago-Ferrero; M. Silvia Díaz-Cruz; Damià Barceló (pp. 2597-2610).

The purpose of this article is to summarize biological monitoring information on UV-absorbing compounds, commonly referred as organic UV filters or sunscreen agents, in aquatic ecosystems. To date a limited range of species (macroinvertebrates, fish, and birds), habitats (lakes, rivers, and sea), and compounds (benzophenones and camphors) have been investigated. As a consequence there is not enough data enabling reliable understanding of the global distribution and effect of UV filters on ecosystems. Both liquid chromatography and gas chromatography coupled with mass spectrometry-based methods have been developed and applied to the trace analysis of these pollutants in biota, enabling the required selectivity and sensitivity. As expected, the most lipophilic compounds occur most frequently with concentrations up to 7112 ng g⁻¹ lipids in mussels and 3100 ng g⁻¹ lipids (homosalate) in fish. High concentrations have also been reported for 4-methylbenzilidenecamphor (up to 1800 ng g⁻¹ lipids) and octocrylene (2400 ng g⁻¹ lipids). Many fewer studies have evaluated the potential bioaccumulation and biomagnification of these compounds in both fresh and marine water and terrestrial food webs. Estimated biomagnification factors suggest biomagnification in predator–prey pairs, for example bird–fish and fish–invertebrates. Ecotoxicological data and preliminary environmental assessment of the risk of UV filters are also included and discussed.

Keywords: UV filters; Biota; Chromatography; Mass spectrometry; Bioaccumulation; Toxicity

Pharmaceuticals in biota in the aquatic environment: analytical methods and environmental implications by B. Huerta; S. Rodríguez-Mozaz; D. Barceló (pp. 2611-2624).

The presence of pharmaceuticals in the aquatic environment is an ever-increasing issue of concern as they are specifically designed to target specific metabolic and molecular pathways in organisms, and they may have the potential for unintended effects on nontarget species. Information on the presence of pharmaceuticals in biota is still scarce, but the scientific literature on the subject has established the possibility of bioaccumulation in exposed aquatic organisms through other environmental compartments. However, few studies have correlated both bioaccumulation of pharmaceutical compounds and the consequent effects. Analytical methodology to detect pharmaceuticals at trace quantities in biota has advanced significantly in the last few years. Nonetheless, there are still unresolved analytical challenges associated with the complexity of biological matrices, which require exhaustive extraction and purification steps, and highly sensitive and selective detection techniques. This review presents the trends in the analysis of pharmaceuticals in aquatic organisms in the last decade, recent data about the occurrence of these compounds in natural biota, and the environmental implications that chronic exposure could have on aquatic wildlife.

Keywords: Pharmaceuticals; Bioaccumulation; Effects; Aquatic organisms; Analytical methods

Dechlorane Plus and related compounds in aquatic and terrestrial biota: a review by M. L. Feo; E. Barón; E. Eljarrat; D. Barceló (pp. 2625-2637).

Dechlorane Plus, dechlorane 602, dechlorane 603 and dechlorane 604 are flame retardants that have been used for a long time as a substitute for mirex, but they have not been noticed as environmental contaminants until recently (2006). Regardless of their large molecular size and very high lipophilicity (log K _OW > 9), Dechlorane Plus and related compounds have been detected in different aquatic and terrestrial species, supporting their bioaccumulation and biomagnification. Moreover, some studies showed different behaviour of the syn-Dechlorane Plus and anti-Dechlorane Plus isomers in the environment and different biomagnification factors in biota. This review describes the different analytical approaches applied to the determination of Dechlorane Plus and related compounds. Moreover, a summary of their levels in aquatic and terrestrial biota, as well as in humans, is presented, showing also current research results on their bioaccumulation and biomagnification potential. Finally, isomer-specific bioaccumulation of Dechlorane Plus is also discussed.

Keywords: Biota; Gas chromatography; Halogenated flame retardants; Halogenated norbornenes; High-resolution mass spectrometry; Tandem mass spectrometry

Organohalogen contaminants of emerging concern in Great Lakes fish: a review by Ray E. Clement; Eric J. Reiner; Satyendra P. Bhavsar (pp. 2639-2658).

Organohalogen chemicals of emerging concern (CECs) have attracted much attention during the past decade and are of special importance for the Great Lakes of North America, which are together the largest surface freshwater resource on the earth. In this paper we review and summarize detection and levels of legacy contaminants in Great Lakes fish, lessons learned from legacy contaminants in advancing the analytical detection of CECs, progress and challenges in measuring CECs, and levels of CECs in Great Lakes fish reported to date. The CECs considered include chlorinated paraffins, polychlorinated naphthalenes and other chlorinated aromatics, halogenated flame retardants, and perfluorinated compounds.

Keywords: Compounds of emerging concern; Chlorinated paraffins; Chlorinated naphthalenes; Halogenated flame retardants; Perfluorinated compounds

Determination of currently used pesticides in biota by Vicente Andreu; Yolanda Picó (pp. 2659-2681).

Although pesticides enable control of the quantity and quality of farm products and food, and help to limit diseases in humans transmitted by insects and rodents, they are regarded as among the most dangerous environmental contaminants because of their tendency to bioaccumulate, and their mobility and long-term effects on living organisms. In the past decade, more analytical methods for accurate identification and quantitative determination of traces of pesticides in biota have been developed to improve our understanding of their risk to ecosystems and humans. Because sample preparation is often the rate-determining step in analysis of pesticides in biological samples, this review first discusses extraction and clean-up procedures, after a brief introduction to the classes, and the methods used in the analysis of pesticides in biota. The analytical methods, especially chromatographic techniques and immunoassay-based methods, are reviewed in detail, and their corresponding advantages, limitations, applications, and prospects are also discussed. This review mainly covers reports published since 2008 on methods for analysis of currently used pesticides in biota.

Keywords: Currently used pesticides; Sample preparation; Chromatographic techniques; Mass spectrometry; Rapid detection methods; Biota; Trace analysis

Determination of perfluorinated alkyl acid concentrations in biological standard reference materials by Jessica L. Reiner; Steven G. O’Connell; Craig M. Butt; Scott A. Mabury; Jeff M. Small; Amila O. De Silva; Derek C. G. Muir; Amy D. Delinsky; Mark J. Strynar; Andrew B. Lindstrom; William K. Reagen; Michelle Malinsky; Sandra Schäfer; Christiaan J. A. F. Kwadijk; Michele M. Schantz; Jennifer M. Keller (pp. 2683-2692).

Standard reference materials (SRMs) are homogeneous, well-characterized materials used to validate measurements and improve the quality of analytical data. The National Institute of Standards and Technology (NIST) has a wide range of SRMs that have mass fraction values assigned for legacy pollutants. These SRMs can also serve as test materials for method development, method validation, and measurement for contaminants of emerging concern. Because inter-laboratory comparison studies have revealed substantial variability of measurements of perfluoroalkyl acids (PFAAs), future analytical measurements will benefit from determination of consensus values for PFAAs in SRMs to provide a means to demonstrate method-specific performance. To that end, NIST, in collaboration with other groups, has been measuring concentrations of PFAAs in a variety of SRMs. Here we report levels of PFAAs and perfluorooctane sulfonamide (PFOSA) determined in four biological SRMs: fish tissue (SRM 1946 Lake Superior Fish Tissue, SRM 1947 Lake Michigan Fish Tissue), bovine liver (SRM 1577c), and mussel tissue (SRM 2974a). We also report concentrations for three in-house quality-control materials: beluga whale liver, pygmy sperm whale liver, and white-sided dolphin liver. Measurements in SRMs show an array of PFAAs, with perfluorooctane sulfonate (PFOS) being the most frequently detected. Reference and information values are reported for PFAAs measured in these biological SRMs. Figure NIST SRMs 1946 Lake Superior Fish Tissue and 1947 Lake Michigan Fish Tissue

Keywords: Perfluoroalkyl acids; Standard reference materials; Fish tissue; Bovine liver; Mussel tissue; Intercomparison exercise

NanoSIMS50 — a powerful tool to elucidate cellular localization of halogenated organic compounds by Arno C. Gutleb; Jaime Freitas; Albertinka J. Murk; Steven Verhaegen; Erik Ropstad; Thomas Udelhoven; Lucien Hoffmann; Jean-Nicolas Audinot (pp. 2693-2698).

Persistent organic pollutants are widely distributed in the environment and lots of toxicological data are available. However, little is known on the intracellular fate of such compounds. Here a method applying secondary ion mass spectrometry is described that can be used to visualize cellular localization of halogenated compounds and to semi-quantitatively calculate concentrations of such compounds. Of the model compounds tested, TBBPA was homogenously distributed in the cell membrane of the H295R cells while PFOS accumulated in very distinct locations in the cell membrane. Relative intracellular concentrations of 4-OH-BDE69 and 4-OH-BDE121 in GH3.TRE were 61 % and 18 %, respectively, compared to the parent compounds. These differences may partly explain that observed effect concentrations for 4-OH-BDEs in in vitro experiments are usually lower than what would be expected based on receptor binding studies. NanoSIMS50 proved to be a powerful tool to describe the cellular distribution of halogenated compounds. The semi-quantitative data that can be obtained may help to further explain results from in vitro or in vivo experiments.

Keywords: Halogenated compounds; Visualization; Intracellular localization

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region by Rui Guo; Eric J. Reiner; Satyendra P. Bhavsar; Paul A. Helm; Scott A. Mabury; Eric Braekevelt; Sheryl A. Tittlemier (pp. 2699-2709).

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

Keywords: Polyfluoroalkyl phosphoric acid diesters (diPAPs); Perfluoroalkyl phosphonic acids (PFPAs); Perfluoroalkyl phosphinic acids (PFPIAs); Perfluoroalkyl carboxylic acids (PFCAs); Perfluoroalkane sulfonic acids (PFSAs); Great lakes; Fish; PFAS

Analysis of selected pharmaceuticals in fish and the fresh water bodies directly affected by reclaimed water using liquid chromatography-tandem mass spectrometry by Jian Wang; Piero R. Gardinali (pp. 2711-2720).

A comprehensive method for the analysis of 11 target pharmaceuticals representing multiple commonly used therapeutic classes was developed for biological tissues (fish), reclaimed water, and the surface water directly affected by irrigation with reclaimed water. One gram of fish tissue homogenate was extracted by accelerated solvent extraction with methylene chloride followed by mixed-mode cation exchange solid phase extraction (SPE) cleanup and analyzed by liquid chromatography-tandem mass spectrometry. Compared to previously reported methods, the protocol produces cleaner extracts resulting in lower method detection limits. Similarly, an SPE method based on Oasis HLB cartridges was used to concentrate and cleanup reclaimed and surface water samples. Among the 11 target compounds analyzed, trimethoprim, caffeine, sulfamethoxazole, diphenhydramine, diltiazem, carbamazepine, erythromycin, and fluoxetine were consistently detected in reclaimed water. Caffeine, diphenhydramine, and carbamazepine were consistently detected in fish and surface water samples. Bioaccumulation factors for caffeine, diphenhydramine, and carbamazepine in mosquito fish (Gambusia holbrooki) were calculated at 29 ± 26, 821 ± 422, and 108 ± 144, respectively. This is the first report of potential accumulation of caffeine in fish from a water body directly influenced by reclaimed water. Figure The pharmaceuticals detected in reclaimed water and the fresh water directly affected by reclaimed water.

Keywords: Pharmaceuticals; Fish; LC-MS/MS

Occurrence of priority and emerging organic compounds in fishes from the Rhone River (France) by C. Miège; A. Peretti; P. Labadie; H. Budzinski; B. Le Bizec; K. Vorkamp; J. Tronczyński; H. Persat; M. Coquery; M. Babut (pp. 2721-2735).

The main objective of this study was to collect new data on the occurrence, levels of priority and emerging organic compounds in freshwater fish sampled in the Rhone River. The 34 studied contaminants included alkylphenols, bisphenol A, polybromodiphenylethers (PBDE), perfluorinated compounds, hexabromocyclododecanes (HBCD), hexachlorobenzene and hexachlorobutadiene (HCBD). About 50 fish samples (individual specimens or pooled fish) were collected from three sites located upstream and downstream of the Lyon metropolitan area in the Rhone River (France). Four species were caught at each site, namely: the barbel (Barbus barbus), the common bream (Abramis brama), the white bream (Blicca bjoerkna) and the chub (Squalius cephalus). Some contaminants were quantified in all the 32 fish samples analysed: 4-nonylphenol, α-HBCD, the six PBDE congeners (28, 47, 99, 100, 153, 154), perfluorooctanesulfonate (PFOS) and perfluorodecanoic acid. Twenty three of the 32 samples had a concentration of PFOS above the Environmental Quality Standards (EQS) (up to six times higher than the EQS), and all the 32 samples had concentrations of PBDE above the EQS (up to 4,000 times higher, with the sum of six PBDE varying from 4.5 to 182 ng/g dry weight). Clearly, the interest to consider PFOS and HBCD as new priority substances is confirmed. In contrast, the pertinence of a priority status for HCBD, which was never quantified in our study, might have to be reconsidered in the future.

Keywords: Emerging compounds; Priority compounds; Fishes; River waters; Contamination level

Identification and determination of the dechlorination products of Dechlorane 602 in Great Lakes fish and Arctic beluga whales by gas chromatography–high resolution mass spectrometry by Li Shen; Karl J. Jobst; Paul A. Helm; Eric J. Reiner; Robert McCrindle; Gregg T. Tomy; Sean Backus; Ian D. Brindle; Chris H. Marvin (pp. 2737-2748).

During the course of our studies of in-use chlorinated flame retardants, such as Dechlorane Plus® and Dechloranes 602 and 604, blubber of beluga whales from the Canadian Arctic and lake trout and whitefish from the North American Great Lakes were found to contain two novel dechlorination products of Dechlorane 602 (Dec602). The structures of these compounds were characterized by experiments performed using both gas chromatography–high resolution mass spectrometry and Fourier transform mass spectrometry with a prepared technical mixture of monohydro and dihydroDec602 derivatives. These Dec602 derivatives are analogous to the well-known monohydro and dihydro photochemical degradation products of Mirex. The ratio of the two monohydroDec602 diastereomers varied between Lake Ontario fish and those from the upper lakes, but only one isomer was found in Arctic beluga, indicating that one isomer is either more stable or more bioaccumulative. Dechlorane Plus®, Dec603, and Dec 604 were not detected in Arctic beluga, but Dec602 and its monohydroDec602 derivative were measured in approximately equal concentrations, ranging from 25 to 300 pg/g lipid. In Great Lakes fish, concentrations of the monohydroDec602 derivatives were also close to those of Dec602, ranging from 2 to 67 ng/g lipid and were greatest in Lake Ontario. This study reports on the first measurements of dechlorane-related compounds in Arctic biota and the first detection of monohydroDec602 degradation products and their accumulation in biota. Figure Dechlorane 602 and its dechlorination product are detected in Great Lakes fish and Arctic beluga

Keywords: Photodegradation; Bioaccumulation; FT-ICR; Dechlorane Plus; Dechlorane 602; Halogenated flame retardants

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 by M. D. Hernando; P. Rosenkranz; M. M. Ulaszewska; M. L. Fernández-Cruz; A. R. Fernández-Alba; J. M. Navas (pp. 2749-2763).

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 (IC₅₀) of 12.96 and 38.31 μg mL^-1 for surface-modified G3 and G4 dendrimers, respectively. No cytotoxic effects, in terms of IC₅₀, 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. Figure Liquid chromatography-electrospray ionization-quadrupole/time-of-flight mass spectrometry (LC-ESI-QTOFMS) based method for quantitative determination of PAMAM dendrimers in cytotoxicity assays

Keywords: Amino-terminated poly(amidoamine) dendrimer; Surface-modified poly(amidoamine) dendrimer; Cytotoxicity; Dose–response assessment; Quantification; Liquid chromatography–electrospray ionization quadrupole/time-of-flight mass spectrometry

Dechlorane Plus in eggs of two gull species (Larus michahellis and Larus audouinii) from the southwestern Mediterranean Sea by Juan Muñoz-Arnanz; Jose Luis Roscales; Alba Vicente; Jose Ignacio Aguirre; Begoña Jiménez (pp. 2765-2773).

Dechlorane Plus (DP) and some of its possible degradation products were measured in eggs from the yellow-legged gull (Larus michahellis) and Audouin's gull (Larus audouinii) from a protected area in the southwestern Mediterranean Sea. Statistically significant differences were found between both gull species, with yellow-legged gull eggs showing the highest average total DP concentration (209 pg/g wet weight). According to stable nitrogen and carbon isotope values, variations in DP concentrations in the gull species studied are explained by foraging behavior and diet rather than by the trophic position. Both DP stereoisomers were quantified in all the samples studied, and a slight enrichment of the anti-DP could have occurred in both species. The quantification of anti-[DP-1Cl] only in ∼58 % of yellow-legged gulls support the hypothesis of a species-dependent factor influencing the bioaccumulation and/or biotransformation of Dechlorane-related compounds. This study reports on the first measurements of Dechlorane-related compounds in biota from the North African continent, contributing to the knowledge about DP environmental fate and distribution. In the light of our results, more research on differences in species-dependent bioaccumulation and biotransformation capabilities as well as ecological effects is encouraged in future Dechlorane-related compound studies.

Keywords: Dechlorane Plus; Degradates; syn-DP; anti-DP; Larus michahellis ; Larus audouinii ; Eggs; Emerging contaminants; Chlorinated flame retardants; Stable isotopes

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Analytical and Bioanalytical Chemistry (v.404, #9)