Validation of a method for the analysis of volatile organic compounds in water

Detalhes bibliográficos
Autor(a) principal: Karmacharya, Amresh Prasad
Data de Publicação: 2015
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10400.1/7843
Resumo: Dissertação de mestrado, Qualidade em Análises, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
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spelling Validation of a method for the analysis of volatile organic compounds in waterAnálises laboratoriaisQualidadeCompostos orgânicosProdutos petrolíferosEspectrometria de massaAnálise cromatográficaDomínio/Área Científica::Ciências Naturais::Ciências QuímicasDissertação de mestrado, Qualidade em Análises, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015Many of the volatile organic compounds (VOCs) which can be harmful to humans have their origin in petroleum products. The VOCs have been found in water sources and leakage from storage tank and accidental spills have been regarded as the main causes of contamination from VOCs. The main objective of this study was to validate detection method of some 15 VOCs by solid-phase microextraction – gas chromatography – mass spectrometry. SPME-GC-MS has been a widely accepted method for analysis of VOCs. The compounds analyzed in this study are; MTBE, 3-ethyltoluene, 4-ethyltoluene, 2-ethyltoluene, 1,2,4-trimethylbenzene, 4-isopropyltoluene, 1,3-diethylbenzene, Indane, 1,4-diethylbenzne, 1,3-dimethyl-5-ethylbenzene, 1,2-diethylbenzene, 1,4-dimethyl-2-ethylbenzenene, 1,3-dimethyl-4-ethylbenzene, 1,2-dimethyl-4-ethylbenzene, 1,2-dimethyl-3-ethylbenzene and hexachlorobutadiene. After separation by the gas chromatograph the compounds were detected in full scan mode and later further studies were carried out in selected ion monitoring (SIM) mode of mass spectrometer. Method validation parameters for the detection of these compounds included selectivity, linear working range, limit of detection (LOD), limit of quantification (LOQ) precision, accuracy and measurement uncertainty. Various statistical tools like regression analysis, residual analysis, Mandel’s test of linearity, RIKILT, and normalized area test were applied to derive and ascertain the results and arrive at a conclusion. The retention time and representative mass fragments were identified for each compound. A linear curve (regression analysis) in the working range was also identified for each of these compounds after suitable dilution of the pure compounds. Working range was between less than 0.1 μg/L and 0.5 μg/L (the minimum and maximum calibration standards) for all the compounds except for MTBE and indane. Linearity was confirmed by residual analysis and Mandel’s test for linearity. Two of the compounds 1,4-diethylbenzene and 1,3-dimethyl-5-ethylbenzene coelute and appear as a single peak in the chromatogram and therefore, their quantity is expressed as the combined quantity of the two. LODs are well above the baseline and LOQs are either equal to or lower than the lowest calibration standards. LOD and LOQ were also quantified from precision data. Precision was studied by determining repeatability and intermediate precision and was expressed as relative standard deviation (RSD %). Council Directive 98/83/EC has prescribed a limit value of 25% for precision. None of the values of repeatability and intermediate precision exceeded the limit of 25%. Accuracy was determined by recovery study of three types of spiked water matrices; tap water, river water and groundwater. Recovery was expressed by comparing the spiked results with the theoretical value (a value provided by the commercial supplier) of a compound in terms of percentage of recovery. Also 10 replicate analysis of the spiked sample gave its precision. Most of the recovery results have been found between 90 and 115%. All the recovery values meet the criterion of 25% recovery set by the Council Directive 98/83/EC. ISO 17025 requires that the laboratories express the results accompanied by the estimated uncertainty. Expanded uncertainty of the method was determined for each compound by combining the component uncertainty of precision, calibration standards and regression interpolation and then multiplying the combined uncertainty by a coverage factor of two for a 95% confidence level. Uncertainty values ranged from 8.2% to 23%. It has been found that for the same compound the uncertainty values for the three different matrices are similar. VOCs targeted in this study can be used as possible indicators of petroleum product contamination of water sources. Each compound has its own retention time and mass spectra which can be used for its detection. Linearity of the working range has been confirmed by various statistical tests. LOD, LOQ and recovery results meet European regulation requirement and this indicates validity of the method and can be applied to detect the compounds in water. HS-SPME sampling is solvent free and less time consuming and therefore is preferable. There has been only limited research in method validation of many target VOCs. So this study contributes to methods of analysis used to detect the target VOCs in different water matrices.Cardoso, Vitor ValeCavaco, IsabelSapientiaKarmacharya, Amresh Prasad2016-03-11T19:17:22Z2015-09-2120152015-09-21T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10400.1/7843TID:202438830enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-24T10:19:01Zoai:sapientia.ualg.pt:10400.1/7843Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:00:07.347004Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Validation of a method for the analysis of volatile organic compounds in water
title Validation of a method for the analysis of volatile organic compounds in water
spellingShingle Validation of a method for the analysis of volatile organic compounds in water
Karmacharya, Amresh Prasad
Análises laboratoriais
Qualidade
Compostos orgânicos
Produtos petrolíferos
Espectrometria de massa
Análise cromatográfica
Domínio/Área Científica::Ciências Naturais::Ciências Químicas
title_short Validation of a method for the analysis of volatile organic compounds in water
title_full Validation of a method for the analysis of volatile organic compounds in water
title_fullStr Validation of a method for the analysis of volatile organic compounds in water
title_full_unstemmed Validation of a method for the analysis of volatile organic compounds in water
title_sort Validation of a method for the analysis of volatile organic compounds in water
author Karmacharya, Amresh Prasad
author_facet Karmacharya, Amresh Prasad
author_role author
dc.contributor.none.fl_str_mv Cardoso, Vitor Vale
Cavaco, Isabel
Sapientia
dc.contributor.author.fl_str_mv Karmacharya, Amresh Prasad
dc.subject.por.fl_str_mv Análises laboratoriais
Qualidade
Compostos orgânicos
Produtos petrolíferos
Espectrometria de massa
Análise cromatográfica
Domínio/Área Científica::Ciências Naturais::Ciências Químicas
topic Análises laboratoriais
Qualidade
Compostos orgânicos
Produtos petrolíferos
Espectrometria de massa
Análise cromatográfica
Domínio/Área Científica::Ciências Naturais::Ciências Químicas
description Dissertação de mestrado, Qualidade em Análises, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
publishDate 2015
dc.date.none.fl_str_mv 2015-09-21
2015
2015-09-21T00:00:00Z
2016-03-11T19:17:22Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10400.1/7843
TID:202438830
url http://hdl.handle.net/10400.1/7843
identifier_str_mv TID:202438830
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
repository.mail.fl_str_mv
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