Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio
Ano de defesa: | 2007 |
---|---|
Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | , |
Tipo de documento: | Dissertação |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Federal de Santa Maria
|
Programa de Pós-Graduação: |
Programa de Pós-Graduação em Química
|
Departamento: |
Química
|
País: |
BR
|
Palavras-chave em Português: | |
Área do conhecimento CNPq: | |
Link de acesso: | http://repositorio.ufsm.br/handle/1/10409 |
Resumo: | A flow injection (FI) system, which is coupled to an atomic absorption spectrometer, is proposed for organic and inorganic mercury speciation. The FI system consists basically of three three way-solenoid valves, a gas/liquid separator and a gold-gauze column. Hg0 and volatile organic mercury species (mainly methylmercury - MeHgH) are generated by reacting inorganic mercury (as Hg(II)) and organic mercury (mainly MeHg+) species with sodium tetraborohydride in HCl medium. The speciation analysis involves two separated steps. In the first, only the volatile mercury obtained by inorganic mercury (Hg(II)) reduction is transported to the quartz cell of the spectrometer where it is measured. In the second step, all volatile mercury species are conducted to a gold-gauze column where they are trapped. Subsequently, the column is heated for mercury releasing, which is then transported to the quartz cell. In this step the total mercury concentration is measured. The concentrations of organic and inorganic mercury are obtained by subtracting the signal measured in the first step from that measured in the second one. The main parameters that influence the FI system performance and mercury speciation were evaluated. The best conditions found were: NaBH4 0.050 % (m/v), HCl 1.0 mol L-1, carrier gas (Ar) flow rate of 25 mL min-1, mercury releasing from the gold-gauze at 500 oC, sample and NaBH4 solutions flow rate of 10 mL min-1 and 2 mL min-1, respectively. The limits of detection, calculated for 10 mL of sample solution processing, were 9.5 ng L-1 of MeHg and 68 ng L-1 of Hg(II). The relative standard deviation (RSD) was typically 2.5%, whereas the calibration curves of Hg(II) and MeHg were linear in the range of 100 to 5000 ng L-1 and 50 to 2000 ng L-1, respectively. The method was applied for organic and inorganic mercury speciation in mineral and underground water. With the proposed FI system it was possible to perform up to 24 measurements per hour. Recovery of spiked organic and inorganic mercury ranged from 97 to 102%. It was concluded that the proposed FI system coupled to atomic absorption spectrometer is very useful and feasible for speciation of very low organic and inorganic mercury. Simplicity, low reagent and sample consumption and good sample throughput are the main characteristics of the system. |
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2017-05-162017-05-162007-01-29TAVARES, Greice Iop. Development and evaluation of a flow injection system for mercury speciation. 2007. 67 f. Dissertação (Mestrado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2007.http://repositorio.ufsm.br/handle/1/10409A flow injection (FI) system, which is coupled to an atomic absorption spectrometer, is proposed for organic and inorganic mercury speciation. The FI system consists basically of three three way-solenoid valves, a gas/liquid separator and a gold-gauze column. Hg0 and volatile organic mercury species (mainly methylmercury - MeHgH) are generated by reacting inorganic mercury (as Hg(II)) and organic mercury (mainly MeHg+) species with sodium tetraborohydride in HCl medium. The speciation analysis involves two separated steps. In the first, only the volatile mercury obtained by inorganic mercury (Hg(II)) reduction is transported to the quartz cell of the spectrometer where it is measured. In the second step, all volatile mercury species are conducted to a gold-gauze column where they are trapped. Subsequently, the column is heated for mercury releasing, which is then transported to the quartz cell. In this step the total mercury concentration is measured. The concentrations of organic and inorganic mercury are obtained by subtracting the signal measured in the first step from that measured in the second one. The main parameters that influence the FI system performance and mercury speciation were evaluated. The best conditions found were: NaBH4 0.050 % (m/v), HCl 1.0 mol L-1, carrier gas (Ar) flow rate of 25 mL min-1, mercury releasing from the gold-gauze at 500 oC, sample and NaBH4 solutions flow rate of 10 mL min-1 and 2 mL min-1, respectively. The limits of detection, calculated for 10 mL of sample solution processing, were 9.5 ng L-1 of MeHg and 68 ng L-1 of Hg(II). The relative standard deviation (RSD) was typically 2.5%, whereas the calibration curves of Hg(II) and MeHg were linear in the range of 100 to 5000 ng L-1 and 50 to 2000 ng L-1, respectively. The method was applied for organic and inorganic mercury speciation in mineral and underground water. With the proposed FI system it was possible to perform up to 24 measurements per hour. Recovery of spiked organic and inorganic mercury ranged from 97 to 102%. It was concluded that the proposed FI system coupled to atomic absorption spectrometer is very useful and feasible for speciation of very low organic and inorganic mercury. Simplicity, low reagent and sample consumption and good sample throughput are the main characteristics of the system.Neste trabalho foi desenvolvido um sistema em fluxo para análise de especiação de mercúrio envolvendo a separação e pré-concentração das espécies de Hg. O sistema foi acoplado a um espectrômetro de absorção atômica. A especiação de Hg é conduzida a partir das determinações seqüenciais de mercúrio (II) e mercúrio total. Na primeira etapa são gerados os vapores de Hg0 a partir de Hg(II) e hidreto de metilmercúrio (HMeHg) a partir do MeHg. Nesta etapa é feita somente a medição de Hg0. Na segunda etapa também são gerados Hg0 e HMeHg, porém as duas espécies na fase vapor são adsorvidas numa coluna de ouro. Após é feita a dessorção térmica das espécies de Hg da coluna e a detecção do Hg0 formado. Desta forma obtém-se a concentração total das espécies voláteis de Hg presentes na amostra. Por diferença se obtém a concentração de MeHg. O sistema em fluxo é composto por três válvulas solenóides, que tem a função de controlar a introdução das soluções de amostra/padrão e de NaBH4, bem como direcionar as espécies voláteis de Hg formadas para a coluna de Au ou diretamente para a cela de leitura do espectrômetro. A dessorção térmica das espécies de Hg da coluna de Au, formando Hg0, é feita através de aquecimento a uma temperatura em torno de 500 0C através de uma lâmpada halógena. Soluções de Hg(II) e MeHg de 100 a 1000 ng L-1 foram utilizadas para avaliar as variáveis que influenciam no sistema proposto, como, vazões de amostra e de argônio e concentrações dos reagentes (HCl e NaBH4). Nas condições estabelecidas para o sistema proposto é possível trabalhar em uma faixa de 100 até 5000 ng L-1 de Hg para determinação de Hg(II) e de 50 a 2000 ng L-1 de Hg para determinação de Hg total. Os limites de detecção calculados foram de 9,5 ng L-1 para MeHg e 68 ng L- 1 para Hg(ll). Com o sistema proposto é possível efetuar 24 medições por hora. O desvio padrão relativo é inferior a 2% na determinação de Hg(II) para uma solução de 500 ng L-1 e inferior a 2,5% para MeHg e 3% para Hg(ll) na determinação do Hg total para soluções de 100 ng L-1. As recuperações dos testes de adição de 10 e 100 ng de Hg total em três amostras de água variaram de 97 a 101%. O sistema FI-CVG AAS proposto para especiação de Hg é caracterizado pela fácil implementação, uso de apenas HCl e NaBH4 como reagentes, baixo consumo de reagentes (2,0 e 0,5 mL, respectivamente) e amostras (2,0 mL para Hg(II) e 6,8 mL para Hg total). Além disso, o sistema é de custo relativamente baixo e adequado para a análise de especiação de mercúrio em amostras de águas naturais.application/pdfporUniversidade Federal de Santa MariaPrograma de Pós-Graduação em QuímicaUFSMBRQuímicaQuímicaQuímica orgânicaMercúrioEspeciaçãoCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICADesenvolvimento e avaliação de sistema em fluxo para especiação de mercúrioDevelopment and evaluation of a flow injection system for mercury speciationinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisDressler, Valderi Luizhttp://lattes.cnpq.br/4054740296547580Saidelles, Ana Paula Fleighttp://lattes.cnpq.br/4797349401105462Paniz, José Neri Gottfriedhttp://lattes.cnpq.br/1216325367920515http://lattes.cnpq.br/9739292775879204Tavares, Greice Iop10060000000040050030030050029c59cfe-a489-425c-88a5-18fdf7cbf258df5047cf-baea-4c81-ab68-6027c2e631904aeebe7b-f94d-4082-93f4-e3b25770664e96786b4b-a5d5-4cd8-a0bb-d7af0080745ainfo:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSMORIGINALGREICETAVARES.pdfapplication/pdf468850http://repositorio.ufsm.br/bitstream/1/10409/1/GREICETAVARES.pdfed553abeba6ffceadc774185332800a5MD51TEXTGREICETAVARES.pdf.txtGREICETAVARES.pdf.txtExtracted texttext/plain133902http://repositorio.ufsm.br/bitstream/1/10409/2/GREICETAVARES.pdf.txtba6086628f2e41bb03887d7d3fa56f49MD52THUMBNAILGREICETAVARES.pdf.jpgGREICETAVARES.pdf.jpgIM Thumbnailimage/jpeg5666http://repositorio.ufsm.br/bitstream/1/10409/3/GREICETAVARES.pdf.jpg774f16d9fba1aa570caad45ccc970bc0MD531/104092022-03-04 16:08:05.562oai:repositorio.ufsm.br:1/10409Repositório Institucionalhttp://repositorio.ufsm.br/PUBhttp://repositorio.ufsm.br/oai/requestopendoar:39132022-03-04T19:08:05Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.por.fl_str_mv |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio |
dc.title.alternative.eng.fl_str_mv |
Development and evaluation of a flow injection system for mercury speciation |
title |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio |
spellingShingle |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio Tavares, Greice Iop Química Química orgânica Mercúrio Especiação CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
title_short |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio |
title_full |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio |
title_fullStr |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio |
title_full_unstemmed |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio |
title_sort |
Desenvolvimento e avaliação de sistema em fluxo para especiação de mercúrio |
author |
Tavares, Greice Iop |
author_facet |
Tavares, Greice Iop |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Dressler, Valderi Luiz |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/4054740296547580 |
dc.contributor.referee1.fl_str_mv |
Saidelles, Ana Paula Fleig |
dc.contributor.referee1Lattes.fl_str_mv |
http://lattes.cnpq.br/4797349401105462 |
dc.contributor.referee2.fl_str_mv |
Paniz, José Neri Gottfried |
dc.contributor.referee2Lattes.fl_str_mv |
http://lattes.cnpq.br/1216325367920515 |
dc.contributor.authorLattes.fl_str_mv |
http://lattes.cnpq.br/9739292775879204 |
dc.contributor.author.fl_str_mv |
Tavares, Greice Iop |
contributor_str_mv |
Dressler, Valderi Luiz Saidelles, Ana Paula Fleig Paniz, José Neri Gottfried |
dc.subject.por.fl_str_mv |
Química Química orgânica Mercúrio Especiação |
topic |
Química Química orgânica Mercúrio Especiação CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA |
description |
A flow injection (FI) system, which is coupled to an atomic absorption spectrometer, is proposed for organic and inorganic mercury speciation. The FI system consists basically of three three way-solenoid valves, a gas/liquid separator and a gold-gauze column. Hg0 and volatile organic mercury species (mainly methylmercury - MeHgH) are generated by reacting inorganic mercury (as Hg(II)) and organic mercury (mainly MeHg+) species with sodium tetraborohydride in HCl medium. The speciation analysis involves two separated steps. In the first, only the volatile mercury obtained by inorganic mercury (Hg(II)) reduction is transported to the quartz cell of the spectrometer where it is measured. In the second step, all volatile mercury species are conducted to a gold-gauze column where they are trapped. Subsequently, the column is heated for mercury releasing, which is then transported to the quartz cell. In this step the total mercury concentration is measured. The concentrations of organic and inorganic mercury are obtained by subtracting the signal measured in the first step from that measured in the second one. The main parameters that influence the FI system performance and mercury speciation were evaluated. The best conditions found were: NaBH4 0.050 % (m/v), HCl 1.0 mol L-1, carrier gas (Ar) flow rate of 25 mL min-1, mercury releasing from the gold-gauze at 500 oC, sample and NaBH4 solutions flow rate of 10 mL min-1 and 2 mL min-1, respectively. The limits of detection, calculated for 10 mL of sample solution processing, were 9.5 ng L-1 of MeHg and 68 ng L-1 of Hg(II). The relative standard deviation (RSD) was typically 2.5%, whereas the calibration curves of Hg(II) and MeHg were linear in the range of 100 to 5000 ng L-1 and 50 to 2000 ng L-1, respectively. The method was applied for organic and inorganic mercury speciation in mineral and underground water. With the proposed FI system it was possible to perform up to 24 measurements per hour. Recovery of spiked organic and inorganic mercury ranged from 97 to 102%. It was concluded that the proposed FI system coupled to atomic absorption spectrometer is very useful and feasible for speciation of very low organic and inorganic mercury. Simplicity, low reagent and sample consumption and good sample throughput are the main characteristics of the system. |
publishDate |
2007 |
dc.date.issued.fl_str_mv |
2007-01-29 |
dc.date.accessioned.fl_str_mv |
2017-05-16 |
dc.date.available.fl_str_mv |
2017-05-16 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/masterThesis |
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masterThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
TAVARES, Greice Iop. Development and evaluation of a flow injection system for mercury speciation. 2007. 67 f. Dissertação (Mestrado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2007. |
dc.identifier.uri.fl_str_mv |
http://repositorio.ufsm.br/handle/1/10409 |
identifier_str_mv |
TAVARES, Greice Iop. Development and evaluation of a flow injection system for mercury speciation. 2007. 67 f. Dissertação (Mestrado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2007. |
url |
http://repositorio.ufsm.br/handle/1/10409 |
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