Analysis of flame retardant additives in polymer fractions of waste of electric and electronic equipment (WEEE) by means of HPLC-UV/MS and GPC-HPLC-UV

An HPLC-UV/MS method has been developed to identify and quantify flame retardants in post-consumer plastics from waste of electric and electronic equipment (WEEE). Atmospheric pressure chemical ionisation spectra of 15 brominated and phosphate-based flame retardants were recorded and interpreted. The method was applied to detect flame retardant additives in polymer extracts obtained from pressurised liquid extraction of solid polymers. In addition, a screening method was developed for soluble styrene polymers to isolate a flame retardant fraction through the application of gel permeation chromatography (GPC). This fraction was transferred to an online-coupled HPLC column and detected by UV spectroscopy, which allowed a reliable qualitative and quantitative analysis of brominated flame retardants in the polymer solutions.     

Oxy-Polybrominated Diphenyl Ethers from the Indonesian Marine Sponge,Lamellodysidea herbacea: X-ray,SAR, and Computational Studies

Polybrominated diphenyl ether (PBDE) compounds, derived from marine organisms, originate from symbiosis between marine sponges and cyanobacteria or bacteria. PBDEs have broad biological spectra; therefore, we analyzed structure and activity relationships of PBDEs to determine their potential as anticancer or antibacterial lead structures, through reactions and computational studies. Six known PBDEs (1–6) were isolated from the sponge, Lamellodysdiea herbacea; ¹³C NMR data for compound 6 are reported for the first time and their assignments are confirmed by their theoretical ¹³C NMR chemical shifts (RMSE < 4.0 ppm). Methylation and acetylation of 1 (2, 3, 4, 5-tetrabromo-6-(3′, 5′-dibromo-2′-hydroxyphenoxy) phenol) at the phenol functional group gave seven molecules (7–13), of which 10, 12, and 13 were new. New crystal structures for 8 and 9 are also reported. Debromination carried out on 1 produced nine compounds (1, 2, 14, 16–18, 20, 23, and 26) of which 18 was new. Debromination product 16 showed a significant IC₅₀ 8.65 ± 1.11; 8.11 ± 1.43 µM against human embryonic kidney (HEK293T) cells. Compounds 1 and 16 exhibited antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae with MID 0.078 µg/disk. The number of four bromine atoms and two phenol functional groups are important for antibacterial activity (S. aureus and K. pneumoniae) and cytotoxicity (HEK293T). The result was supported by analysis of frontier molecular orbitals (FMOs). We also propose possible products of acetylation and debromination using analysis of FMOs and electrostatic charges and we confirm the experimental result.     

Preparation of reference materials for the determination of RoHS-relevant flame retardants in styrenic polymers

Reference materials for the analysis of polybrominated diphenyl ethers, polybrominated biphenyls and other common brominated flame retardants (FR) in styrenic polymers were prepared to suit the demands of actual restriction of the use of certain hazardous substances in electrical and electronic equipment analytics. Three methods of preparation were employed, viz. pellet forming, dissolution/vaporisation and extrusion, whereby extrusion proved to be the most suitable method. For extrusion, three procedures of pre-mixing were investigated: the polymers were either mixed with FR powder, FR solutions or FR concentrates that were taken from waste industrial polymers. The latter procedure proved to be most appropriate in terms of analyte concentration, predictability and recovery. The homogeneity of the samples, as well as the chemical and thermal long-term stabilities, was investigated. The result was an optimised method to prepare a suitable reference material for laboratory use. Figure   Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Prediction of gas collection efficiency and particle collection artifact for atmospheric semivolatile organic compounds in multicapillary denuders

A modeling approach is presented to predict the sorptive sampling collection efficiency of gaseous semivolatile organic compounds (SOCs) and the artifact caused by collection of particle-associated SOCs in multicapillary diffusion denuders containing polydimethylsiloxane (PDMS) stationary phase. Approaches are presented to estimate the equilibrium PDMS–gas partition coefficient (K_pdms) from a solvation parameter model for any compound, and, for nonpolar compounds, from the octanol–air partition coefficient (K_oa) if measured K_pdms values are not available. These estimated K_pdms values are compared with K_pdms measured by gas chromatography. Breakthrough fraction was measured for SOCs collected from ambient air using high-flow (300 L min⁻¹) and low-flow (13 L min⁻¹) denuders under a range of sampling conditions (−10 to 25 °C; 11–100% relative humidity). Measured breakthrough fraction agreed with predictions based on frontal chromatography theory using K_pdms and equations of Golay, Lövkvist and Jönsson within measurement precision. Analytes included hexachlorobenzene, 144 polychlorinated biphenyl congeners, and polybrominated diphenyl ethers 47 and 99. Atmospheric particle transmission efficiency was measured for the high-flow denuder (0.037–6.3 μm diameter), and low-flow denuder (0.015–3.1 μm diameter). Particle transmission predicted using equations of Gormley and Kennedy, Pich, and a modified filter model, agreed within measurement precision (high-flow denuder) or were slightly greater than (low-flow denuder) measured particle transmission. As an example application of the model, breakthrough volume and particle collection artifact for the two denuder designs were predicted as a function of K_oa for nonpolar SOCs. The modeling approach is a necessary tool for the design and use of denuders for sorptive sampling with PDMS stationary phase.     

Separation of polychlorinated dibenzo-p-dioxins/furans,non-ortho/mono/di/tri/tetra-ortho-polychlorinated biphenyls,and polybrominated diphenyl ethers groups of compounds prior to their determination with large volume injection gas chromatography—Quadrupole ion storage tandem mass spectrometry

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are important environmental contaminants. Their maximum legally allowable levels in food and environment are in the low pg g⁻¹ range. Therefore some highly selective and sensitive analytical methods must be used to determine them. Prior to final determination by GC/MS the cleaned-up samples have to be split into some fractions in view of large differences in concentrations of various analytes and existence of numerous chromatographic co-elutions (which in any case cannot be fully avoided). The aim of this study was to: (i) develop a robust, time-saving analytical method to isolate, clean-up and fractionate PCBs, PBDEs and PCDD/Fs prior to their determination with gas chromatography/ion trap mass spectrometry; (ii) assess method performance using laboratory validation data and some certified reference materials; (iii) use the developed method to assess PCB/PBDE/PCDD/F levels in samples of commercially available food. A combination of alumina, florisil, modified silica gel and two carbon columns were used for sample cleanup and fractionation. Separate fractions containing dioxins/furans, PBDE, non-ortho, mono-ortho and di-/tri-/tetra-ortho PCBs were obtained. The method statistical parameters were compatible with 1883/2006 EC Regulation (80–120%, RSD below 15%). The method performance was successfully used to evaluation of some real life food samples.     

Determination of polybrominated diphenyl ethers in soil by ultrasonic assisted extraction and gas chromatography mass spectrometry

An analytical method for the determination of polybrominated diphenyl ethers (PBDEs) in soil was developed. Soil samples were placed in small glass columns and PBDEs extracted from soil, with a low volume of ethyl acetate (5 mL, 2× 15 min), assisted by sonication. PBDEs were determined by gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC–MS–SIM) and residues were confirmed by their retention times, selected ions and qualifier–target abundance ratios. Recovery studies were performed at 10, 1, 0.1 and 0.05 μg/kg fortification levels, and the recoveries obtained ranged from 81 to 104% with a relative standard deviation between 1 and 9%. The detection limit of the method varied from 2 to 30 pg/g and the quantification limit ranged from 7 to 100 pg/g for the different PBDEs studied. The developed method was linear over the range assayed, 0.01–10 μg/kg with determination coefficients equal or higher than 0.997. The proposed method was used to determine PBDEs levels in soil samples from different areas of Spain and PBDEs were detected in some samples with values ranging from 1.3 to 5.6 μg/kg.     

Analytical chemistry of the persistent organic pollutants identified in the Stockholm Convention: A review

Persistent organic pollutants (POPs) are major environmental concern due to their persistence, long-range transportability, bio-accumulation and potentially adverse effects on living organisms. Analytical chemistry plays an essential role in the measurement of POPs and provides important information on their distribution and environmental transformations. Much effort has been devoted during the last two decades to the development of faster, safer, more reliable and more sensitive analytical techniques for these pollutants. Since the Stockholm Convention (SC) on POPs was adopted 12 years ago, analytical methods have been extensively developed. This review article introduces recent analytical techniques and applications for the determination of POPs in environmental and biota samples, and summarizes the extraction, separation and instrumental analyses of the halogenated POPs. Also, this review covers important aspects for the analyses of SC POPs (e.g. lipid determination and quality assurance/quality control (QA/QC)), and finally discusses future trends for improving the POPs analyses and for potential new POPs.     

40 Years of Research on Polybrominated Diphenyl Ethers (PBDEs)—A Historical Overview and Newest Data of a Promising Anticancer Drug

Polybrominated diphenyl ethers (PBDEs) are a group of molecules with an ambiguous background in literature. PBDEs were first isolated from marine sponges of Dysidea species in 1981 and have been under continuous research to the present day. This article summarizes the two research aspects, (i) the marine compound chemistry research dealing with naturally produced PBDEs and (ii) the environmental toxicology research dealing with synthetically-produced brominated flame-retardant PBDEs. The different bioactivity patterns are set in relation to the structural similarities and dissimilarities between both groups. In addition, this article gives a first structure–activity relationship analysis comparing both groups of PBDEs. Moreover, we provide novel data of a promising anticancer therapeutic PBDE (i.e., 4,5,6-tribromo-2-(2′,4′-dibromophenoxy)phenol; termed P01F08). It has been known since 1995 that P01F08 exhibits anticancer activity, but the detailed mechanism remains poorly understood. Only recently, Mayer and colleagues identified a therapeutic window for P01F08, specifically targeting primary malignant cells in a low µM range. To elucidate the mechanistic pathway of cell death induction, we verified and compared its cytotoxicity and apoptosis induction capacity in Ramos and Jurkat lymphoma cells. Moreover, using Jurkat cells overexpressing antiapoptotic Bcl-2, we were able to show that P01F08 induces apoptosis mainly through the intrinsic mitochondrial pathway.     

Effect of polybrominated diphenyl ether on development of cultured hippocampal neuron

Polybrominated diphenyl ether (PBDE) is a persistently environmental pollutant ubiquitously found in wildlife and humans. Although concern on PBDE’s toxic effects is steadily increasing, its action on the central nervous system (CNS) remains largely unknown. To address this issue, the present study ex- amined the development inhibition of PBDE in neurons. The primary cultured hippocampal neurons of rat were exposed to the commercial decabromodiphenyl ether (deca-BDE), and the neurite length, bi- furcation, and synapse formation and maturation were evaluated, based on the confocal microscope imaging. The results showed that the development inhibition in neurons occurred at 15 μmol/L, indi- cating that PBDE is a potent neurotoxicant and it might obviously inhibit the development of cultured neurons.