Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 48
Filtrar
1.
Mar Pollut Bull ; 193: 115251, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37421912

RESUMO

This study presents an important long-term historical analysis of water quality in an internationally crucial waterway (the Solent, Hampshire, UK), in the context of increasing adoption of open-loop Exhaust Gas Cleaning Systems by shipping. The pollutants studied were acidification (pH), zinc, and benzo [a] pyrene, alongside temperature. We compared baseline sites to locations likely to be impacted by pollution. The Solent's average water temperature is slightly increasing, with temperatures at wastewater sites significantly higher. Acidification suggests a complex story, with a highly significant small overall increase in pH during the study period but significantly different values at wastewater and port sites. Zn concentrations have significantly reduced but increased in enclosed waters such as marinas. BaP showed no long-term trend with values at marinas significantly and consistently higher. The findings provide valuable long-term background data and insights that can feed into the upcoming review of the European Union's Marine Strategy Framework Directive and ongoing discussions about the regulation of, and future monitoring and management strategies for coastal/marine waterways.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Qualidade da Água , Monitoramento Ambiental , Águas Residuárias , Poluentes Ambientais/análise , Emissões de Veículos/análise , Poluentes Químicos da Água/análise
2.
Mar Pollut Bull ; 186: 114450, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36502777

RESUMO

A long-term historical analysis of the impacts of recreational boating on marine surface water quality during a regatta (Cowes Week) in an internationally crucial waterway, the Solent Strait (Hampshire, UK) is presented. Water quality indicators studied included nitrogen concentration, bacterial indicators, and oxygen saturation, at three sampling sites at/near Cowes during 2001-2019. Findings include that sewage discharge from recreational boats is the key contributor to localised faecal contamination of marine surface waters, putting bathers and shellfisheries at risk. Bathing water quality monitoring and pollution warning systems should be strengthened prior to and during this type of regatta and access to bathing water areas may need to be restricted. These findings have implications for the regulation, future monitoring and management strategies for discharges from recreational boats during extended regattas. Adequate and affordable local facilities for recovering sewage wastewater from recreational boats should be provided alongside appropriate mechanisms for communication to sailors.


Assuntos
Qualidade da Água , Esportes Aquáticos , Esgotos/microbiologia , Recreação , Bactérias , Microbiologia da Água , Monitoramento Ambiental
3.
Heliyon ; 8(7): e09862, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35874052

RESUMO

Enhanced biological phosphorus removal at wastewater treatment plants that use anaerobic digesters for sludge treatment have historically encountered phosphate precipitation problems in the form of struvite. Literature on struvite is thin which is surprising given it can foul/block the sludge return lines and associated pumps and valves, causing significant operational problems. This study has evaluated if a typical large wastewater treatment plant can overcome this problem by adopting circular economy thinking. The struvite profile based on the supersaturation ratio of (Mg:NH4:PO4 2-), pH and temperature demonstrates the potential operational hotspots that can present uncontrolled struvite formation. Based on current struvite monitoring technologies and a cost-benefit analysis, the controlled struvite recovery via an Ostara crystallization reactor has been demonstrated to be economically viable with a pay-back period of less than a decade. An integrated evaluation illustrates the positive environmental impact arising from the utilisation of the recovered product. Economic viability and payback periods will vary according to circumstances, but we recommend that WWTP operators globally consider fitting a crystallisation reactor to appropriate plants, The outcomes and recommendation from this study are particularly timely given the global fertiliser shortage (2022) that is driving up food prices and reducing crop sizes.

4.
Waste Manag ; 70: 222-235, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28918870

RESUMO

Separate household food waste collection for anaerobic digestion is one method used in the sustainable management of biodegradable municipal solid waste (MSW). Recycling of food waste contributes to the UK's reuse, recycling and composting targets and can help local authorities boost plateauing rates whilst encouraging landfill diversion. This study explored the reasons for differences in the provision of food waste collections, using two comparable local authorities, one with a collection in Wales (Cardiff), and the other absent of such service in England (Southampton). A PESTLE analysis investigated the political, economic, social, technological, legal and environmental impacts of separate food waste collections. The greenhouse gas impacts of the collection and treatment systems of MSW in both cities were estimated for 2012/13. Results showed significant policy and legislative differences between devolved governments, that separate food waste collections can save local authorities significant sums of money and substantially reduce greenhouse gas impacts. A survey of one hundred respondents in each city aimed to understand attitudes and behaviours towards recycling, food waste segregation, cooking and purchasing habits. The number of frequent recyclers and levels of satisfaction were higher in the authority which provided a separate food waste collection. In the area which lacked a separate collection service, over three-quarters of respondents would participate in such a scheme if it were available.


Assuntos
Resíduos de Alimentos , Resíduos Sólidos/estatística & dados numéricos , Gerenciamento de Resíduos/métodos , Inglaterra , Características da Família , Habitação/estatística & dados numéricos , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , País de Gales
5.
Waste Manag ; 60: 1-2, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28254345
6.
Sci Total Environ ; 575: 1279-1290, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-27707664

RESUMO

The Manila clam (Ruditapes philippinarum), an invasive species in Northern Europe, can be used as a bioindicator of metal pollution. Seasonal effects on metallothionein (MT) production have not been considered in this species at the northernmost extent of its European distribution. This study assesses the annual seasonal effects on MT and metal concentrations in R. philippinarum from Poole Harbour, UK. R. philippinarum were collected in winter, spring, summer, and autumn throughout 2015, and MT and metal concentrations, as well as biotic and abiotic variables, were quantified. During winter, linear regression analysis showed significant positive relationships between tissue metal and MT concentrations. However, during spring and summer, these relationships were mostly insignificant. MT concentrations during spring had significant positive relationships with tissue and whole weight. Significant positive relationships were also observed between MT and condition index, during summer. During spring and summer, biotic factors seem to override the role of MT as a detoxification mechanism for metal exposure in this species. This is probably due to an increase in MT concentration in spring caused by gametogenesis, associated with increased tissue weight as the gonads expand. A depletion of energy resources, or physical stressors such as heat, may be attributed to the reduced MT production in clams of poor body condition in summer. The evidence from this study suggests that MT may only be a useful biomarker of metal pollution during winter in R. philippinarum in the UK. This verifies the natural variability of MT in this species at high latitudes, and highlights the potential and limits to a widely available bioindicator of metal pollution.


Assuntos
Bivalves/metabolismo , Metalotioneína/metabolismo , Metais/química , Estações do Ano , Poluentes Químicos da Água/química , Animais , Monitoramento Ambiental , Estuários , Europa (Continente)
7.
Environ Pollut ; 208(Pt A): 209-220, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26412197

RESUMO

This paper presents a performance evaluation framework for streetscape vegetation. A performance index (PI) is conceived using the following seven traits, specific to the street environments - Pollution Flux Potential (PFP), Carbon Sequestration Potential (CSP), Thermal Comfort Potential (TCP), Noise Attenuation Potential (NAP), Biomass Energy Potential (BEP), Environmental Stress Tolerance (EST) and Crown Projection Factor (CPF). Its application is demonstrated through a case study using fifteen street vegetation species from the UK, utilising a combination of direct field measurements and inventoried literature data. Our results indicate greater preference to small-to-medium size trees and evergreen shrubs over larger trees for streetscaping. The proposed PI approach can be potentially applied two-fold: one, for evaluation of the performance of the existing street vegetation, facilitating the prospects for further improving them through management strategies and better species selection; two, for planning new streetscapes and multi-functional biomass as part of extending the green urban infrastructure.


Assuntos
Poluição do Ar/prevenção & controle , Sequestro de Carbono , Planejamento de Cidades/métodos , Ruído/prevenção & controle , Árvores/crescimento & desenvolvimento , Biomassa , Tomada de Decisões , Ecossistema , Reino Unido
8.
Sci Total Environ ; 538: 478-91, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26318685

RESUMO

Short-term exposure to air pollution has been associated with exacerbation of asthma and chronic obstructive pulmonary disease (COPD). This study investigated the relationship between emergency hospital admissions for asthma, COPD and episodes of poor air quality in an English city (Southampton) from 2008-2013. The city's council provides a forecasting service for poor air quality to individuals with respiratory disease to reduce preventable admissions to hospital and this has been evaluated. Trends in nitrogen dioxide, ozone and particulate matter concentrations were related to hospital admissions data using regression analysis. The impacts of air quality on emergency admissions were quantified using the relative risks associated with each pollutant. Seasonal and weekly trends were apparent for both air pollution and hospital admissions, although there was a weak relationship between the two. The air quality forecasting service proved ineffective at reducing hospital admissions. Improvements to the health forecasting service are necessary to protect the health of susceptible individuals, as there is likely to be an increasing need for such services in the future.


Assuntos
Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Comunicação em Saúde/métodos , Poluentes Atmosféricos , Exposição Ambiental/prevenção & controle , Hospitalização , Humanos , Dióxido de Nitrogênio , Ozônio , Material Particulado , Admissão do Paciente , Saúde Pública , Análise de Regressão , Doenças Respiratórias/epidemiologia , Doenças Respiratórias/prevenção & controle , Risco , Estações do Ano
9.
Waste Manag ; 44: 15-27, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26233881

RESUMO

A waste audit and a household questionnaire survey were conducted in high-density housing estates in one of the most economically and socially deprived areas of England (Haringey, London). Such areas are under-represented in published research. The study examined source segregation, potential participation in a food waste segregation scheme, and food waste prevention activities in five estates (1034 households). The results showed that: contamination of recyclables containers was low; ca. 28% of the mixed residual waste's weight was recyclable; food waste comprised a small proportion of the waste from these residents, probably because of their relatively disadvantaged economic circumstances; and the recycling profile reflected an intermittent pattern of behaviour. Although the majority of respondents reported that they would participate in a food waste separation scheme, the response rate was low and many responses of "don't know" were recorded. Municipalities committed to foster improved diversion from landfill need to recognise that there is no "quick and easy fix", regardless of local or national aspirations. Lasting and sustained behaviour change requires time and the quality of service provision and associated infrastructure play a fundamental role in facilitating residents to participate effectively in waste management activities that maximise capture of source-segregated materials. Populations in deprived areas that reside in high-rise, high-density dwellings are "hard-to-reach" in terms of participation in recycling schemes and exceptional efforts and additional resources are usually required to improve performance.


Assuntos
Atitude , Resíduos de Alimentos , Reciclagem , Eliminação de Resíduos , Londres , Motivação , Densidade Demográfica
10.
Waste Manag ; 45: 4-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26066575

RESUMO

Fear of scarcity of resources highlight the need to exploit secondary materials from urban mines in the anthroposphere. Analogous to primary mines rich in one type of material (e.g. copper, gold, etc.), some urban mines are unique/distinct. We introduce, illustrate and discuss the concept of Distinct Urban Mines (DUM). Using the example of a university DUM in the UK, analogous to a primary mine, we illustrate potential product/material yields in respect of size, concentration and spatial location of the mine. Product ownership and replacement cycles for 17 high-value electrical and electronic equipment (EEE) among students showed that 20 tonnes of valuable e-waste were in stockpile in this DUM and a further 87 tonnes would 'soon' be available for exploitation. We address the opportunities and challenges of exploiting DUMs and conclude that they are readily available reservoirs for resource recovery. Two original contributions arise from this work: (i) a novel approach to urban mining with a potential for maximising resource recovery within the anthroposphere is conceptualised; and (ii) previously unavailable data for high-value products for a typical university DUM are presented and analysed.


Assuntos
Resíduo Eletrônico/análise , Mineração , Reciclagem/métodos , Gerenciamento de Resíduos/métodos , Cidades , Reino Unido
13.
Waste Manag ; 39: 266-76, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25771762

RESUMO

European nations are compelled to reduce reliance on landfill as a destination for household waste, and should, in principle, achieve this goal with due recognition of the aims and principles of the waste hierarchy. Past research has predominantly focused on recycling, whilst interactions between changing waste destinies, causes and drivers of household waste management change, and potential consequences for the goal of the waste hierarchy are less well understood. This study analysed Local Authority Collected Waste (LACW) for England, at national, regional and sub-regional level, in terms of the destination of household waste to landfill, incineration and recycling. Information about waste partnerships, waste management infrastructure and collection systems was collected to help identify and explain changes in waste destinies. Since 1996, the proportion of waste landfilled in England has decreased, in tandem with increases in recycling and incineration. At the regional and sub-regional (Local Authority; LA) level, there have been large variations in the relative proportions of waste landfilled, incinerated and recycled or composted. Annual increases in the proportion of household waste incinerated were typically larger than increases in the proportion recycled. The observed changes took place in the context of legal and financial drivers, and the circumstances of individual LAs (e.g. landfill capacity) also explained the changes seen. Where observed, shifts from landfill towards incineration constitute an approach whereby waste management moves up the waste hierarchy as opposed to an attempt to reach the most preferred option(s); in terms of resource efficiency, this practice is sub-optimal. The requirement to supply incinerators with a feedstock over their lifespan reduces the benefits of developing of recycling and waste reduction, although access to incineration infrastructure permits short-term and marked decreases in the proportion of LACW landfilled. We conclude that there is a need for clearer national strategy and co-ordination to inform and guide policy, practice, planning and investment in infrastructure such that waste management can be better aligned with the principles of the circular economy and resource efficiency. If the ongoing stand-off between national political figures and the waste sector continues, England's waste policy remains destined for indecision.


Assuntos
Reciclagem/métodos , Instalações de Eliminação de Resíduos , Gerenciamento de Resíduos/métodos , Inglaterra , Incineração
14.
Sci Total Environ ; 518-519: 238-47, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-25765376

RESUMO

Metallothionein (MT) is established as a potentially useful biomarker for monitoring aquatic pollution. This paper addresses widespread inconsistencies in storage conditions, tissue type selection and pre-treatment of samples before MT and metal analysis in biomarker studies. This variation hampers comparability and so the widespread implementation of this monitoring approach. Actively sampled Mytilus edulis in Southampton Water, UK were exposed to different storage temperatures, a variety of tissue types were analysed, and various pre-treatments of transportation on ice, transportation in seawater, depuration, and rapid dissection in the field were examined. Storage temperatures of -20 °C were found to be adequate for periods of at least ten weeks, as MT was not reduced by protein degradation compared with samples kept at -80 °C. Whole tissue and digestive gland concentrations of MT and metals were significantly positively correlated and directly relatable. MT in the digestive gland appeared to be more responsive to metals than in whole tissue, where it may be diluted, masking MT responses. However, longer study periods may suffer the effects of mass changes to the digestive gland, which alters MT concentration, and it may therefore be advisable to measure whole tissue. Depuration and transportation in seawater reduced both MT and metal concentrations in the digestive gland, and few correlations between MT and metals were identified for these treatments. It is therefore recommended that: i) samples are transported to the laboratory on ice and dissected as soon as possible thereafter, ii) depuration should not be used when examining MT response to metal exposure until further research clarifying its utility is reported, iii) either whole tissue or the digestive gland can be used to measure MT, though whole tissue may be preferable on long-term studies, and iv) organisms can be stored at -20 °C before analysis for up to ten weeks. These practices can be applied to future biomonitoring studies and will improve the comparability and repeatability of using MT as a biomarker.


Assuntos
Monitoramento Ambiental/métodos , Metalotioneína/metabolismo , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Organismos Aquáticos , Biomarcadores/metabolismo , Mytilus edulis , Água do Mar
15.
Environ Pollut ; 203: 262-270, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25690986

RESUMO

Anaerobic digestion (AD) of putrescible urban waste for energy recovery has seen rapid growth over recent years. In order to ascertain its systems scale sustainability, however, determination of the environmental fate of the large volume of digestate generated during the process is indispensable. This paper evaluates the environmental burdens to air associated with land applied food-based digestate in terms of primary pollutants (ammonia, nitrogen dioxide) and greenhouse gases (methane and nitrous oxide). The assessments have been made in two stages - first, the emissions from surface application of food-based digestate are quantified for the business as usual (BAU). In the next step, environmental burden minimisation potentials for the following three mitigation measures are estimated - mixed waste digestate (MWD), soil-incorporated digestate (SID), and post-methanated digestate (PMD). Overall, the mitigation scenarios demonstrated considerable NH3, CH4 and N2O burden minimisation potentials, with positive implications for both climate change and urban pollution.


Assuntos
Monitoramento Ambiental , Poluição Ambiental , Gerenciamento de Resíduos , Amônia , Anaerobiose , Mudança Climática , Gases/análise , Metano/análise , Óxido Nitroso/análise , Solo/química
16.
Sci Total Environ ; 473-474: 391-7, 2014 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-24378929

RESUMO

Poole Harbour is typical of many heavily anthropologically impacted semi-enclosed estuarine coastal areas under pressure from metal pollution across the world. This study examined the physiological significance of metal burdens within that sensitive area, and assessed the potential use of metallothionein (MT) concentrations in two organisms: the common cockle (Cerastoderma edule) and the Mermaid's glove sponge (Haliclona oculata) for mapping the spatial extent of the biological response to metal contamination. A spectrophotometric method was applied for detection of MT in the bivalve, and for the first time to detect MT in sponges. The results show that while some metal concentrations in cockle and sponge tissues and in their surrounding environment (water and sediment) could be related to sources of metal contamination, MT values in the soft tissue of cockles and whole tissue of sponges are not. No relation could be found between MT in both cockles and sponges, and any of the tested metals (As, Cd, Cr, Cu, Pb, Hg, Ni, Ag, Sn, Zn). Furthermore, some of the lowest MT concentrations were detected in heavily polluted areas, indicating that MT concentrations in tested organisms are not exclusively associated with metal concentrations, as other environmental factors could affect induction of this protein. Organisms probably have a high tolerance to metal contamination and chronic exposure to a high level of contamination resulted in developing a variety of detoxification mechanisms. Results indicate that further study of metal stress in this type of ecosystem may need to examine other indicator species and/or apply a different biomonitoring technique.


Assuntos
Cardiidae/metabolismo , Monitoramento Ambiental/métodos , Haliclona/metabolismo , Metalotioneína/metabolismo , Metais/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Biomarcadores/metabolismo , Ecossistema
17.
Proc Biol Sci ; 281(1774): 20131835, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24258715

RESUMO

On coral reefs, herbivorous fishes consume benthic primary producers and regulate competition between fleshy algae and reef-building corals. Many of these species are also important fishery targets, yet little is known about their global status. Using a large-scale synthesis of peer-reviewed and unpublished data, we examine variability in abundance and biomass of herbivorous reef fishes and explore evidence for fishing impacts globally and within regions. We show that biomass is more than twice as high in locations not accessible to fisheries relative to fisheries-accessible locations. Although there are large biogeographic differences in total biomass, the effects of fishing are consistent in nearly all regions. We also show that exposure to fishing alters the structure of the herbivore community by disproportionately reducing biomass of large-bodied functional groups (scraper/excavators, browsers, grazer/detritivores), while increasing biomass and abundance of territorial algal-farming damselfishes (Pomacentridae). The browser functional group that consumes macroalgae and can help to prevent coral-macroalgal phase shifts appears to be most susceptible to fishing. This fishing down the herbivore guild probably alters the effectiveness of these fishes in regulating algal abundance on reefs. Finally, data from remote and unfished locations provide important baselines for setting management and conservation targets for this important group of fishes.


Assuntos
Recifes de Corais , Peixes/fisiologia , Animais , Biodiversidade , Biomassa , Conservação dos Recursos Naturais , Pesqueiros , Geografia , Herbivoria , Densidade Demográfica , Dinâmica Populacional
18.
Waste Manag ; 33(12): 2600-6, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24045170

RESUMO

In Europe, socio-economic enterprises such as charities, voluntary organisations and not-for-profit companies are involved in the repair, refurbishment and reuse of various products. This paper characterises and analyses the operations of socio-economic enterprises that are involved in the reuse of Information and Communication Technology (ICT) equipment. Using findings from a survey, the paper specifically analyses the reuse activities of socio-economic enterprises in the U.K. from which Europe-wide conclusions are drawn. The amount of ICT products handled by the reuse organisations is quantified and potential barriers and opportunities to their operations are analysed. By-products from reuse activities are discussed and recommendations to improve reuse activities are provided. The most common ICT products dealt with by socio-economic enterprises are computers and related equipment. In the U.K. in 2010, an estimated 143,750 appliances were reused. However, due to limitations in data, it is difficult to compare this number to the amount of new appliances that entered the U.K. market or the amount of waste electrical and electronic equipment generated in the same period. Difficulties in marketing products and numerous legislative requirements are the most common barriers to reuse operations. Despite various constraints, it is clear that organisations involved in reuse of ICT could contribute significantly to resource efficiency and a circular economy. It is suggested that clustering of their operations into "reuse parks" would enhance both their profile and their products. Reuse parks would also improve consumer confidence in and subsequently sales of the products. Further, it is advocated that industrial networking opportunities for the exchange of by-products resulting from the organisations' activities should be investigated. The findings make two significant contributions to the current literature. One, they provide a detailed insight into the reuse operations of socio-economic enterprises. Previously unavailable data has been presented and analysed. Secondly, new evidence about the by-products/materials resulting from socio-economic enterprises' reuse activities has been obtained. These contributions add substantially to our understanding of the important role of reuse organisations.


Assuntos
Computadores/estatística & dados numéricos , Telecomunicações/instrumentação , Resíduo Eletrônico , Reutilização de Equipamento , Organizações , Reino Unido
19.
Sci Total Environ ; 445-446: 29-40, 2013 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-23314120

RESUMO

Residual waste is commonly collected separately from recyclable and organic materials. Different forms of collection and disposal are used internationally since regional or municipal authorities have to adapt to their own circumstances. Many authorities have adopted an alternate weekly collection (AWC) of residual waste and recyclables to force/encourage householders to recycle; however, the degree to which they achieve waste reduction has yet to be reliably quantified. This study reports on how the introduction of AWCs affects household waste arisings. The paper evaluates single and dual stream collection methods and compares their performance with the previous system. Household waste collection trials were conducted between March and June 2009 in England (Lichfield). The trials examined changes to frequency of collection, type of container issued, amounts of sorting required of residents, household participation and productivity levels. A survey of households was completed before any changes were implemented. The quantity of recyclates collected was examined for 2008/2009 and 2009/2010. The study showed that the AWC scheme positively impacted on recycling rates and household behaviour, with no adverse impacts on public participation, household waste arisings or the local environment. No public health problems were reported. Both trials saw an increase in the quantities of recyclates collected per household during the trial period compared to the same period of time in the previous year. The dual stream performed better than the single stream, collecting an average of 5.94 kg/hh/week compared to an average of 5.63 kg/hh/week. The single stream system showed a greater increase in the weight of material collected (0.53 kg/hh/week vs. 0.48 kg/hh/week). Participation and set-out rates showed an increase during the trial period. The single stream option (comingled materials in one container) outperformed the dual stream service. The reduction in costs and improved productivity were the principal reasons used for extending the trial and making changes to the district's waste collections. The study clearly demonstrates the benefits of local authorities and universities collaborating and identifies practical logistical and operational issues that need to be anticipated.


Assuntos
Reciclagem/métodos , Gerenciamento de Resíduos/métodos , Conservação dos Recursos Naturais , Inglaterra , Produtos Domésticos , Fatores de Tempo
20.
Phys Chem Chem Phys ; 14(18): 6289-97, 2012 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-22322861

RESUMO

Laser induced acoustic desorption (LIAD) has been used for the first time to study the parent ion production and fragmentation mechanisms of a biological molecule in an intense femtosecond (fs) laser field. The photoacoustic shock wave generated in the analyte substrate (thin Ta foil) has been simulated using the hydrodynamic HYADES code, and the full LIAD process has been experimentally characterised as a function of the desorption UV-laser pulse parameters. Observed neutral plumes of densities >10(9) cm(-3) which are free from solvent or matrix contamination demonstrate the suitability and potential of the source for studying ultrafast dynamics in the gas phase using fs laser pulses. Results obtained with phenylalanine show that through manipulation of fundamental femtosecond laser parameters (such as pulse length, intensity and wavelength), energy deposition within the molecule can be controlled to allow enhancement of parent ion production or generation of characteristic fragmentation patterns. In particular by reducing the pulse length to a timescale equivalent to the fastest vibrational periods in the molecule, we demonstrate how fragmentation of the molecule can be minimised whilst maintaining a high ionisation efficiency.


Assuntos
Acústica , Gases/química , Lasers , Fenilalanina/química , Temperatura , Cinética , Tantálio/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA