RESUMO
NIR-II fluorescence imaging-guided photothermal therapy (PTT) has been widely investigated due to its great application potential in tumor theranostics. PTT is an effective and non-invasive tumor treatment method that can adapt to tumor hypoxia; nevertheless, simple and effective strategies are still desired to develop new materials with excellent PTT properties to meet clinical requirements. In this work, we developed a bromine-substitution strategy to enhance the PTT of A-D-A'-D-A π-conjugated molecules. The experimental results reveal that bromine substitution can notably enhance the absorptivity (ϵ) and photothermal conversion efficiency (PCE) of the π-conjugated molecules, resulting in the brominated molecules generating two times more heat (ϵ808â nm ×PCE) than their unsubstituted counterpart. We disclose that the enhanced photothermal properties of bromine-substituted π-conjugated molecules are a combined outcome of the heavy-atom effect, enhanced ICT effect, and more intense bromine-mediate intermolecular π-π stacking. Finally, the NIR-II tumor imaging capability and efficient PTT tumor ablation of the brominated π-conjugated materials demonstrate that bromine substitution is a promising strategy for developing future high-performance NIR-II imaging-guided PTT agents.
Assuntos
Nanopartículas , Neoplasias , Humanos , Fototerapia , Bromo/uso terapêutico , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Terapia Fototérmica , Linhagem Celular Tumoral , Nanomedicina Teranóstica/métodosRESUMO
In recent years, isoquinoline-1,3(2H,4H)-dione compounds have attracted extensive attention from synthetic chemists, with the aim of finding simple, mild, green and efficient synthetic methods. In this review, we summarize the diverse range of synthetic methods employing acryloyl benzamides as key substrates to furnish isoquinoline-1,3-diones using different radical precursors, such as those containing carbon, sulphur, phosphorus, nitrogen, silicon and bromine. This will stimulate the interest of readers to engage in research in this field.
Assuntos
Bromo , Silício , Isoquinolinas/química , Benzamidas/química , Nitrogênio , Fósforo , Enxofre , CarbonoRESUMO
This work aimed to establish a novel determination method for acrylamide in coffee and its products by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acrylamide in samples were prepared by a single-step solid-phase extraction clean-up using mixed mode sorbents. The bromine derivatization efficiency of acrylamide and its internal standard were improved at an acidic condition. After derivation, the retention capability of acrylamide and its resistance to interference were significantly improved. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.2 and 4 µg/kg for roasted and instant coffees, while they were 0.24 and 0.8 µg/kg for ready-to-drink coffees. The average recoveries for acrylamide ranged from 99.3 to 102.2% in coffee and its products. All the results showed that the developed method was simple, quick, specific and suitable for screening and determination of acrylamide in batch samples of coffee and its products.
Assuntos
Acrilamida , Café , Acrilamida/análise , Bromo/análise , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida/métodos , Café/química , Isótopos , Extração em Fase Sólida , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem/métodosRESUMO
The effectiveness of a recycling approach of the printed circuit board (PCBs), and, thus, the quality of polymeric constituents, primarily rests on the capacity to eliminate the bromine content (mainly as HBr). HBr is emitted in appreciable quantities during thermal decomposition of PCB-contained brominated flame retardants (BFRs). The highly corrosive, yet relatively reactive HBr, renders recovery of bromine-free hydrocarbons streams from brominated polymers in PCBs very challenging. Via combined experimental and theoretical frameworks, this study explores the potential of deploying alumina (Al2O3) as a debromination agent of Br-containing hydrocarbon fractions in PCBs. A consensus from a wide array of characterization techniques utilized herein (ICP-OES, IC, XRD, FTIR, SEM-EDX, and TGA) clearly demonstrates the transformation of alumina upon its co-pyrolysis with the non-metallic fractions of PCBs, into aluminum bromides and oxy-bromides. ICP-OES measurements disclose the presence of high concentration of Cu in the non-metallic fraction of PCB, along with minor levels of selected valuable metals. Likewise, elemental ionic analysis by IC demonstrates an elevated concentration of bromine in washed alumina-PCBs pyrolysates, especially at 500 °C. The Coats-Redfern model facilitates the derivation of thermo-kinetic parameters underpinning the thermal degradation of alumina-PCB mixtures. Density functional theory calculations (DFT) establish an accessible reaction pathway for the HBr uptake by the alumina surface, thus elucidating chemical reactions governing the observed alumina debromination activity. Findings from this study illustrate the capacity of alumina as a HBr fixation agent during the thermal treatment of e-waste.
Assuntos
Resíduo Eletrônico , Retardadores de Chama , Óxido de Alumínio , Bromo , Resíduo Eletrônico/análise , Pirólise , ReciclagemRESUMO
A method for the simultaneous determination of arsenobetaine, arsenite, arsenate, dimethylarsinic acid, monomethylarsonic acid, selenite, selenate, bromate, bromide, iodate, and iodide in bottled drinking water and fruit juice samples was established by using high-performance liquid chromatography-inductively coupled plasma mass spectrometry. The separation of eleven compounds was performed on an ion exchange chromatography column (Dionex IonPac AS14) with 20 mmol L-1 (NH4)2CO3 (pH 10) and 50 mmol L-1 (NH4)2CO3 (pH 10) as a mobile phase. The limits of quantification of the method were 0.17 - 1.2 µg L-1 for the test compounds in bottled drinking water and 0.34 - 2.4 µg L-1 in fruit juice. The average recoveries ranged from 85.8 to 102.2%, and the relative standard deviations (RSDs) obtained in fortification recovery studies were generally <4.2% for bottled drinking water samples. The average recoveries ranged from 88.1 to 118.0% (except for iodate) for fruit juice sample.
Assuntos
Arsênio , Água Potável , Iodo , Selênio , Arsênio/análise , Bromo , Cromatografia Líquida de Alta Pressão , Sucos de Frutas e Vegetais , Iodetos , Espectrometria de Massas , Selênio/análiseRESUMO
Total reflection X-ray fluorescence analysis (TXRF) was used to determine chromium, selenium and bromine concentrations in blood serum samples of 50 patients with parenteral nutrition treatment. The concentrations were measured two times, namely in the first day (I measurement) of the treatment and the seventh day (II measurement) after the chromium and selenium supplementation. For comparison purposes also serum samples of 50 patients without nutritional disorders, admitted to a planned surgical procedure to remove the gall bladder (cholecystectomy), were analyzed and treated as the control group. Descriptive statistics of measured concentrations of Cr, Se and Br both for the studied and control groups was determined. In order to check the effectiveness of Cr and Se supplementation, the results of the first and seventh day measurements for studied group were statistically compared with each other, with literature reference values and with the results of the control group (two-group comparison). These comparisons indicate the effectiveness of selenium supplementation in the applied treatment procedure. In the case of Cr and Br concentrations no statistically significant differences were observed. We conclude that monitoring of the concentration of the important trace elements in human serum should be standard procedure in parenteral nutrition treatment. In this monitoring the TXRF technique can be successfully used.
Assuntos
Bromo/sangue , Cromo/sangue , Nutrição Parenteral , Selênio/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Bromo/normas , Estudos de Casos e Controles , Cromo/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Selênio/normas , Espectrometria por Raios X/normasRESUMO
Dengue infection is one of the most deleterious public health concerns for two-billion world population being at risk. Plasma leakage, hemorrhage, and shock in severe cases were caused by immunological derangement from secondary heterotypic infection. Flavanone, commonly found in medicinal plants, previously showed potential as anti-dengue inhibitors for its direct antiviral effects and suppressing the pro-inflammatory cytokine from dengue immunopathogenesis. Here, we chemically modified flavanones, pinocembrin and pinostrobin, by halogenation and characterized them as potential dengue 2 inhibitors and performed toxicity tests in human-derived cells and in vivo animal model. Dibromopinocembrin and dibromopinostrobin inhibited dengue serotype 2 at the EC50s of 2.0640 ± 0.7537 and 5.8567 ± 0.5074 µM with at the CC50s of 67.2082 ± 0.9731 and >100 µM, respectively. Both of the compounds also showed minimal toxicity against adult C57BL/6 mice assessed by ALT and Cr levels in day one, three, and eight post-intravenous administration. Computational studies suggested the potential target be likely the NS5 methyltransferase at SAM-binding pocket. Taken together, these two brominated flavanones are potential leads for further drug discovery investigation.
Assuntos
Antivirais/farmacologia , Bromo/química , Dengue/tratamento farmacológico , Flavanonas/farmacologia , Animais , Antivirais/química , Vírus da Dengue/efeitos dos fármacos , Desenho de Fármacos , Descoberta de Drogas , Flavanonas/toxicidade , Células HEK293 , Células Hep G2 , Humanos , Infusões Intravenosas , Iodo/química , Espectroscopia de Ressonância Magnética , Metiltransferases/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Ligação ProteicaRESUMO
Chemical representations derived from deep learning are emerging as a powerful tool in areas such as drug discovery and materials innovation. Currently, this methodology has three major limitations - the cost of representation generation, risk of inherited bias, and the requirement for large amounts of data. We propose the use of multi-task learning in tandem with transfer learning to address these limitations directly. In order to avoid introducing unknown bias into multi-task learning through the task selection itself, we calculate task similarity through pairwise task affinity, and use this measure to programmatically select tasks. We test this methodology on several real-world data sets to demonstrate its potential for execution in complex and low-data environments. Finally, we utilise the task similarity to further probe the expressiveness of the learned representation through a comparison to a commonly used cheminformatics fingerprint, and show that the deep representation is able to capture more expressive task-based information.
Assuntos
Aprendizado Profundo , Bromo/química , Carbono/química , Cloro/química , Flúor/química , Hidrogênio/química , Iodo/química , Metais/química , Nitrogênio/química , Oxigênio/química , Fósforo/química , Enxofre/químicaRESUMO
Fish muscle may constitute one of the main sources of iodine (I) for the indigenous peoples of the Russian Arctic, although limited information is available about its content in commonly consumed fish species. In the current study, bromine (Br), I, the essential elements (copper, selenium and zinc) and other non-essential elements - specifically mercury, arsenic (As), cadmium, lead and nickel - have been quantified in 10 fish species consumed by people living in the Nenets and Chukotka Regions. Fish muscle was analysed by ICP-MS after nitric acid or tetramethylammonium hydroxide digestion. Certified reference materials were employed and concentrations are reported as geometric means (GMs). Atlantic cod (6.32 mg/kg) and navaga (0.934 mg/kg) contained substantially higher amounts of I than all other fish species, while broad whitefish had the lowest (0.033 mg/kg). By comparison, navaga contained more Br (14.5 mg/kg) than the other fish species, ranging 7.45 mg/kg in Atlantic cod to 2.39 mg/kg in northern pike. A significant inter-fish association between As and I in freshwater and marine fish was observed, suggesting common sources and perhaps parallel absorption patterns. Only Atlantic cod and, to lesser extent, navaga constituted significant dietary sources of I.
Assuntos
Bromo/análise , Produtos Pesqueiros/análise , Peixes/metabolismo , Povos Indígenas , Iodo/análise , Animais , Regiões Árticas , Arsênio/análise , Cádmio/análise , Cobre/análise , Água Doce , Humanos , Mercúrio/análise , Federação Russa , Água do Mar , Selênio/análise , Zinco/análiseRESUMO
We investigated the mechanisms involved in the development of airway hyperresponsiveness (AHR) following exposure of mice to halogens. Male mice (C57BL/6; 20-25 g) exposed to either bromine (Br2) or Cl2 (600 or 400 ppm, respectively, for 30 min) developed AHR 24 h after exposure. Nifedipine (5 mg/kg body wt; an L-type calcium channel blocker), administered subcutaneously after Br2 or Cl2 exposure, produced higher AHR compared with Br2 or Cl2 alone. In contrast, diltiazem (5 mg/kg body wt; a nondihydropyridine L-type calcium channel blocker) decreased AHR to control (air) values. Exposure of immortalized human airway smooth muscle cells (hASMC) to Br2 resulted in membrane potential depolarization (Vm Air: 62 ± 3 mV; 3 h post Br2:-45 ± 5 mV; means ± 1 SE; P < 0.001), increased intracellular [Ca2+]i, and increased expression of the calcium-sensing receptor (Ca-SR) protein. Treatment of hASMC with a siRNA against Ca-SR significantly inhibited the Br2 and nifedipine-induced Vm depolarization and [Ca2+]i increase. Intranasal administration of an antagonist to Ca-SR in mice postexposure to Br2 reversed the effects of Br2 and nifedipine on AHR. Incubation of hASMC with low-molecular-weight hyaluronan (LMW-HA), generated by exposing high-molecular-weight hyaluronan (HMW-HA) to Br2, caused Vm depolarization, [Ca2+]i increase, and Ca-SR expression to a similar extent as exposure to Br2 and Cl2. The addition of HMW-HA to cells or mice exposed to Br2, Cl2, or LMW-HA reversed these effects in vitro and improved AHR in vivo. We conclude that detrimental effects of halogen exposure on AHR are mediated via activation of the Ca-SR by LMW-HA.
Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Cálcio/metabolismo , Ácido Hialurônico/farmacologia , Músculo Liso/efeitos dos fármacos , Receptores de Detecção de Cálcio/metabolismo , Hipersensibilidade Respiratória/tratamento farmacológico , Viscossuplementos/farmacologia , Animais , Bromo/toxicidade , Células Cultivadas , Cloretos/toxicidade , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Peso Molecular , Músculo Liso/metabolismo , Receptores de Detecção de Cálcio/antagonistas & inibidores , Receptores de Detecção de Cálcio/genética , Hipersensibilidade Respiratória/induzido quimicamente , Hipersensibilidade Respiratória/metabolismo , Hipersensibilidade Respiratória/patologiaRESUMO
Identifying and monitoring dietary toxicants is an important component of contemporary food safety systems. To characterise their potential dietary risks, analysis was undertaken of 10 elements: antimony, barium, beryllium, boron, bromine, lithium, nickel, strontium, thallium and uranium in 132 different food types. All 10 elements were reported as quantified in aportion of the analysed foods, with prevalence ranging from less than 1% for antimony to 98% for barium. Dietary exposure assessment was undertaken for 10 New Zealand population cohorts using apublished simulated diet, and proportionality of food groups to total exposure identified. Characterisation against health-based guidance values identified no dietary risk from exposures to beryllium, boron, bromine, lithium, strontium and uranium to any of the population cohorts. For antimony and thallium, the exposure range for infants was calculated to exceed the health-based guidance value, and for barium and nickel, all mean exposures were above the health-based guidance value for younger population cohorts. Although some conservatism in applying upper-bound mean exposures reduces the likelihood of asignificant dietary risk, further laboratory method development and analysis of these elements in the New Zealand diet would be beneficial to ensure protection of New Zealand public health.
Assuntos
Exposição Dietética , Contaminação de Alimentos/análise , Oligoelementos/análise , Antimônio , Bário/análise , Berílio , Boro , Bromo , Humanos , Lítio , Nova Zelândia , Níquel , Medição de Risco , Estrôncio , Tálio , UrânioRESUMO
Instrumental neutron activation analysis (INAA) has been used to determine the concentration of some toxic chemical elements in a variety of aromatic plants samples collected from Djelfa region. In the present work, eight medicinal plants were examined, such as Artemisia herba-alba Asso., Artemisia compestris L., Laurus nobilis L., Origanum vulgare L., Mentha spicata L., Rosmarinus officinalis L., Mentha pulegium L., and Pistacia lentiscus L. The levels of toxic elements were compared to their daily total intake; Arsenic was present in all plant species examined, with a concentration ranging from 0.18 to 5.44 µg g- 1. Bromine was also detected in all the medicinal plant species, with high concentrations, compared to arsenic except in the case of Laurus nobilis that has the highest concentration of arsenic. Cerium, cobalt, chromium, and antimony were presented in all plant species. The exactitude of the results was assessed by analyzing the certified reference material of SRM-NIST 1573a and CRM GB07605 (GSV4). These data analysis for this medicinal plant can be useful for therapeutics and pharmaceutical purposes.
Assuntos
Antimônio/análise , Arsênio/análise , Bromo/análise , Cério/análise , Cromo/análise , Cobalto/análise , Plantas Medicinais/química , Plantas Medicinais/toxicidade , Argélia , Antimônio/toxicidade , Arsênio/toxicidade , Bromo/toxicidade , Cério/toxicidade , Cromo/toxicidade , Cobalto/toxicidadeRESUMO
BACKGROUND: Otitis media with effusion (OME) is an ear disorder defined by the presence of fluid in the middle ear without signs or symptoms of acute infection. The aim of this randomised and controlled pilot study was to evaluate whether the treatment with a watery salsobromo- iodine solution, administered by nasal douche, could induce ear healing better than isotonic saline in children with OME. METHODS: The study was randomized, single-blind, and controlled. Study group (40 children) was treated with salso-bromo-iodine thermal water solution and Control group (40 children) was treated with isotonic saline; both compounds were administered by nasal nebulization with Rinowash nasal douche twice/day for 10 days a month for 3 consecutive months. Tympanogram and audiometry were performed at baseline and after treatment. RESULTS: Salso-bromo-iodine therapy shows better and statistically significant trend after treatment when compared to control group both for tympanogram results with greater improvement (represented by type C tympanogram; p = 0.031) and healing (represented by type A tympanogram; p < 0.001) and audiometric results, with higher presence of patients with normal hearing (p = 0.029) and lower among patients with moderate hypoacusis (p = 0.014). CONCLUSIONS: The current randomized-controlled pilot study demonstrated that watery salso-bromo-iodine solution was effective in the treatment of children with OME.
Assuntos
Bromo/uso terapêutico , Iodo/uso terapêutico , Otite Média com Derrame/tratamento farmacológico , Cloreto de Sódio/uso terapêutico , Testes de Impedância Acústica , Administração Intranasal , Audiometria , Bromo/administração & dosagem , Criança , Pré-Escolar , Combinação de Medicamentos , Feminino , Perda Auditiva/tratamento farmacológico , Humanos , Iodo/administração & dosagem , Masculino , Projetos Piloto , Método Simples-Cego , Cloreto de Sódio/administração & dosagemRESUMO
BACKGROUND: The limited integration of ethics in nutrition-related public health policies and interventions is one major concern for those who have the task of implementing them. Ethical challenges that are overlooked during the development of such interventions could raise serious ethical issues during their implementation and even after. As a result, these decision makers need technical support and ethical guidance for adaptation of interventions to local (cultural, social, economic, etc.) contexts. AIM: The goal of this scoping review is to delineate and "map" the range of ethical issues in nutrition-related public health interventions, as well as the range of the various fields in which they may arise. METHODS: A scoping review of empirical research and conceptual literature was conducted following the framework of Arksey and O'Malley. Searches using PubMed with Medical Subject Headings (MeSH) categories and Advanced Search Builder as well as in the Global Health Library were performed. The final sample consists of 169 publications. RESULTS: The ethics of public health prevention or treatment of obesity and non-communicable diseases is the most explicitly and frequently discussed subject. In comparison, ethical issues raised by public health interventions in the fields of undernutrition, breastfeeding, vitamin/mineral supplementation and food fortification, food security, food sustainability and food safety are addressed in a lower proportion of the sample. The results illustrate the various natures, types, and scopes of existing public health nutrition-related interventions, and the various ethical issues that may be raised by these interventions, in addition to the numerous and different contexts in which they may be implemented. DISCUSSION: The ethical issues faced in the development and implementation of nutrition-related public health interventions are varied and cannot be equated with, nor generalized about, when dealing with specific activities in this field. More importantly, these ethical issues cannot be managed without a careful consideration for the complexity of contexts in which nutrition-related interventions are expected to be implemented. These interventions engage a variety of actors with diverse perspectives and interests. We discuss these challenges and also comment on the importance of considering ethical impacts in the monitoring and evaluation of such interventions. CONCLUSION: General ethical frameworks or recommendations-although useful-cannot be expected to provide policy makers, implementators and other public health personnel with sufficient practical ethical guidance as they cannot consider and anticipate the particularities of all specific nutrition-related public health interventions and the complexity of the contexts in which they are implemented. Further research is needed in order to develop more targeted ethical frameworks.
Assuntos
Ética , Política de Saúde , Estado Nutricional , Saúde Pública , Bromo/química , Humanos , Estados UnidosRESUMO
The foundational goal of structural DNA nanotechnology-the field that uses oligonucleotides as a molecular building block for the programmable self-assembly of nanostructured systems-was to use DNA to construct three-dimensional (3D) lattices for solving macromolecular structures. The programmable nature of DNA makes it an ideal system for rationally constructing self-assembled crystals and immobilizing guest molecules in a repeating 3D array through their specific stereospatial interactions with the scaffold. In this work, we have extended a previously described motif (4 × 5) by expanding the structure to a system that links four double-helical layers; we use a central weaving oligonucleotide containing a sequence of four six-base repeats (4 × 6), forming a matrix of layers that are organized and dictated by a series of Holliday junctions. In addition, we have assembled mirror image crystals (l-DNA) with the identical sequence that are completely resistant to nucleases. Bromine and selenium derivatives were obtained for the l- and d-DNA forms, respectively, allowing phase determination for both forms and solution of the resulting structures to 3.0 and 3.05 Å resolution. Both right- and left-handed forms crystallized in the trigonal space groups with mirror image 3-fold helical screw axes P32 and P31 for each motif, respectively. The structures reveal a highly organized array of discrete and well-defined cavities that are suitable for hosting guest molecules and allow us to dictate a priori the assembly of guest-DNA conjugates with a specified crystalline hand.
Assuntos
DNA/química , Bromo/química , Cristalização , Cristalografia por Raios X , Modelos Moleculares , Nanoestruturas/química , Nanotecnologia , Conformação de Ácido Nucleico , Oligonucleotídeos/química , Selênio/química , EstereoisomerismoRESUMO
Numerous furanoids have been reported to be toxic, and many of them were found in herbal medicines. Toxicities of furanoids are suggested to result from the generation of cis-enedials via biotransformation. The detection of the electrophilic metabolic intermediates is a challenge. Earlier, we developed a selective approach to screen potential toxic furanoids, through which we found two major furanoids, diosbulbin B and 8-epidiosbulbin E acetate, in Dioscorea bulbifera L., a known furanoid-containing and hepatotoxic herbal medicine. In the present study, we improved the approach to analyze furanoids in D. bulbifera L., which allowed us to detect additional six potential furanoids, including diosbulbin A, diosbulbin D, diosbulbin E, diosbulbin F, diosbulbin M, and diosbulbin D glycoside. The achievements of this study enhanced the sensitivity to screen potential toxic furanoids through elevating S/N values by approximately 3 times. This will facilitate the understanding of mechanisms of toxic actions of D. bulbifera L. and other furanoid-containing toxic herbal medicines.
Assuntos
Bromo , Dioscorea/química , Diterpenos/análise , Furanos/análise , Compostos Heterocíclicos de 4 ou mais Anéis/análise , Lactonas/análise , Animais , Bromo/análise , Bromo/química , Células Cultivadas , Medicamentos de Ervas Chinesas/efeitos adversos , Medicamentos de Ervas Chinesas/química , Microssomos Hepáticos/química , Extratos Vegetais/química , Extratos Vegetais/toxicidade , Ratos , Ratos Sprague-Dawley , Sensibilidade e Especificidade , Espectrometria de Massas em Tandem , Testes de ToxicidadeRESUMO
Flame retardants (FRs) are useful because they can prevent combustion and delay the spread of fire after the ignition on commercial products containing plastics. However, such commercial products could be a primary source of environmental contamination with FRs. Plastic disks containing FRs were prepared to elucidate changes in the concentrations of the FRs after weathering tests. Acrylonitrile-butadiene-styrene (ABS) and polycarbonate (PC) resin were separately kneaded with a combination of three organic FRs [Dechlorane plus (DP), tetrabromobisphenol A (TBBPA), and triphenyl phosphate (TPhP)] and one inorganic FR [antimony trioxide (Sb2O3)]. The concentrations of TBBPA/TPhP and DP/Sb2O3 in the final preparations were respectively 1000 and 500 mg/kg in compliance with the RoHS directive on organobromine FR. The concentrations of elements in the final preparations were 300 mg/kg for chlorine, 600 mg/kg for bromine, 100 mg/kg for phosphorus, and 400 mg/kg for antimony, respectively. The analytical concentrations (three FRs and four elements) were consistent with the expected concentrations (maximum difference -9.5% in the PC disks). The FRs and elements in the disks were sufficiently homogenous (maximum inhomogeneity 4.3% in the PC disks). The prepared disks were subjected to weathering tests; the concentrations of TBBPA in the disks decreased significantly (30 to 40%) whereas the concentrations of the elements did not change under the condition of this study. On the other hand, there were no drastic differences on relationships of FRs and elements such as DP/chlorine and TPhP/phosphorus.
Assuntos
Monitoramento Ambiental , Retardadores de Chama/análise , Plásticos/química , Antimônio/análise , Bromo/análise , Cloro/análise , Hidrocarbonetos Clorados/análise , Organofosfatos/análise , Fósforo/análise , Bifenil Polibromatos/análise , Compostos Policíclicos/análiseRESUMO
The exoskeleton of crustaceans consists mainly of calcium carbonate (CaCO3) minerals and in many cases exhibits vivid colouration due to the presence of proteins rich in carotenoid chromophores. The exposure of aquatic animals in sea water results often in the incorporation of trace elements in their exoskeleton. The bonding configuration of Br and Sr trace elements in regions with different staining (white, orange and blue) of the exoskeleton of the Callinectes sapidus in crab claw are systematically investigated by a number of complementary spectroscopic techniques, including X-ray absorption fine structure spectroscopy (EXAFS), X-ray fluorescence, Raman and visible light reflectivity spectroscopies. It is found that Sr substitutes for Ca and the Sr/Ca ratio is constant along the claw. In the orange region that includes the claw fingers, CaCO3 adopts a calcite-like structure, whereas in the blue and white regions, located in the palm of the claw, an aragonite-like structure dominates. On the other hand, Br, present only in the blue and orange stained parts of the claw, is bound to phenyl and/or phenol rings of amino acid residues, most probably to phenylalanine and/or tyrosine, of the chromophore protein.
Assuntos
Braquiúros/anatomia & histologia , Aminoácidos/metabolismo , Animais , Braquiúros/química , Braquiúros/metabolismo , Bromo/metabolismo , Carbonato de Cálcio/química , Cor , Casco e Garras/química , Análise Espectral , Estrôncio/química , Espectroscopia por Absorção de Raios XRESUMO
In response to concerns regarding the widespread use of flame retardants, the California Legislature passed a law (SB1019) requiring labels on furniture products to indicate whether they do or do not contain flame retardants. To support the enforcement of the new law, our laboratory developed a step-wise, screening approach to test for brominated (BFR) and phosphorus-based flame retardants (OPFRs) in several types of furniture components (foam, fabric, batting, plumage, etc.). We used X-Ray Fluorescence (XRF) to screen for the presence of Br (and other elements) and Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES) to identify and measure the concentration of P (and other elements). The same samples were also extracted by dichloromethane using sonication and analyzed by a single injection into a Gas Chromatograph - Tandem Mass Spectrometer to obtain concentrations of specific BFRs and OPFRs. Our approach showed excellent screening potential for Br and Sb by XRF and for P by ICP-OES, with both tests having predictive values of a negative equal to 1. To explore and screen for flame retardants in products not included in our current list of target chemicals, we used Liquid Chromatography/Time-of-Flight Mass Spectrometry operated with electrospray ionization, to identify additional flame retardants to be incorporated in quantitative methods. We are making all our methodologies public to facilitate simple and low cost methods that can help manufacturers and suppliers have their products tested and correctly labeled, ultimately benefitting the consumer.
Assuntos
Retardadores de Chama/análise , Decoração de Interiores e Mobiliário , Antimônio/análise , Bromo/análise , California , Cromatografia Líquida , Qualidade de Produtos para o Consumidor/legislação & jurisprudência , Cromatografia Gasosa-Espectrometria de Massas , Decoração de Interiores e Mobiliário/legislação & jurisprudência , Fósforo/análise , Rotulagem de Produtos/legislação & jurisprudência , Espectrometria de Massas em Tandem , Raios XRESUMO
Tea is one of the most common and popular beverages spanning vast array of cultures all over the world. The main nutritional benefits of drinking tea are its anti-oxidant properties, presumed protection against certain cancers, inhibition of inflammation and possible protective effects against diabetes. Laser induced breakdown spectrometer (LIBS) was assembled as a powerful tool for qualitative and quantitative analysis of various brands of tea samples using 266 nm pulsed UV laser. LIBS spectra for six brands of tea samples in the wavelength range of 200-900 nm was recorded and all elements present in our tea samples were identified. The major toxic elements detected in several brands of tea samples were bromine, chromium and minerals like iron, calcium, potassium and silicon. The spectral assignment was conducted prior to the determination of concentration of each element. For quantitative analysis, calibration curves were drawn for each element using standard samples prepared in known concentration in the tea matrix. The plasma parameters (electron temperature and electron density) were also determined prior to the tea samples spectroscopic analysis. The concentration of iron, chromium, potassium, bromine, copper, silicon and calcium detected in all tea samples was between 378-656, 96-124, 1421-6785, 99-1476, 17-36, 2-11 and 92-130 mg L(-1) respectively. The limits of detection estimated for Fe, Cr, K, Br, Cu, Si, Ca in tea samples were 22, 12, 14, 11, 6, 1 and 12 mg L(-1) respectively. To further confirm the accuracy of our LIBS results, we determined the concentration of each element present in tea samples by using standard analytical technique like ICP-MS. The concentrations detected with our LIBS system are in excellent agreement with ICP-MS results. The system assembled for spectral analysis in this work could be highly applicable for testing the quality and purity of food and also pharmaceuticals products.