Publicação
Environmental analytical chemistry: development and comparison of simple chemiluminescent and bioluminescent methods to analyze air particulate samples
| Resumo: | The harmful effects of atmospheric pollution’s particulate matter on the human organism have been proven and studied since a long time ago. Innumerous methods have been developed through time to test the composition of air particulate matter and its effect on the human body. A lot of reliable complex methods exist, but there seems to be a need for a simple, affordable, sensitive and accurate method that most laboratories could use to test their own air samples. Two simple methods were developed to analyze particulate matter samples in two highly polluted Italian cities – Quiliano and Vado Ligure, both from the region of Liguria – one chemiluminescent and one bioluminescent method. The chemiluminescent method was based on the reaction between luminol and peroxidase in the presence of oxidizing solution, producing an amount of light directly proportional to the amount of oxidizing compound in the sample. So luminol/enhancer and peroxidase solutions were added to the samples and the light emission was measured using a luminometer. The ability to determine samples’ toxicity is related with the major toxic effect of particulate matter being oxidative stress. By comparing the samples’ luminescence kinetics over time and their maximum signals to previously analyzed heavy metals’ samples we were able to identify the samples’ main compound and quantity’s order of magnitude. On the other hand, the bioluminescent method used naturally luminescent UCIBO bacteria – genetically modified Vibrio fischeri – to evaluate the toxic effect of the samples in living organisms. This way, highly luminescent bacteria were added directly to the samples and their pattern of luminescence signal was compared to healthy colonies, being the difference in luminescence maximum signal a direct proportion of the samples’ toxicity over bacteria. Both methods proved simple and fast to execute, affordable and sensitive. The bioluminescent method showed better accuracy than the chemiluminescent one (12.13% versus 21.50% mean standard deviation), even though both methods developed need improvements to ensure higher accuracy and become more reliable. A direct relation between both methods results was not possible to establish as while the chemiluminescent method focuses more on the amounts of oxidizing material in the samples, the bioluminescent one assesses their toxicity. A sample may have higher values of oxidizing components, giving higher values with the chemical method, and produce less toxic effects than another with lower amount of oxidizing materials, not displaying so high results with the biological method as the second sample. We concluded that both methods can and should be used together, in order to obtain more valuable and complete information about the air pollution samples. |
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| Autores principais: | Amorim, Miguel David Santos |
| Assunto: | Atmospheric pollution Particulate matter Chemiluminescence Bioluminescence Luminol UCIBO V. fischeri Mestrado Integrado - 2016 |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | The harmful effects of atmospheric pollution’s particulate matter on the human organism have been proven and studied since a long time ago. Innumerous methods have been developed through time to test the composition of air particulate matter and its effect on the human body. A lot of reliable complex methods exist, but there seems to be a need for a simple, affordable, sensitive and accurate method that most laboratories could use to test their own air samples. Two simple methods were developed to analyze particulate matter samples in two highly polluted Italian cities – Quiliano and Vado Ligure, both from the region of Liguria – one chemiluminescent and one bioluminescent method. The chemiluminescent method was based on the reaction between luminol and peroxidase in the presence of oxidizing solution, producing an amount of light directly proportional to the amount of oxidizing compound in the sample. So luminol/enhancer and peroxidase solutions were added to the samples and the light emission was measured using a luminometer. The ability to determine samples’ toxicity is related with the major toxic effect of particulate matter being oxidative stress. By comparing the samples’ luminescence kinetics over time and their maximum signals to previously analyzed heavy metals’ samples we were able to identify the samples’ main compound and quantity’s order of magnitude. On the other hand, the bioluminescent method used naturally luminescent UCIBO bacteria – genetically modified Vibrio fischeri – to evaluate the toxic effect of the samples in living organisms. This way, highly luminescent bacteria were added directly to the samples and their pattern of luminescence signal was compared to healthy colonies, being the difference in luminescence maximum signal a direct proportion of the samples’ toxicity over bacteria. Both methods proved simple and fast to execute, affordable and sensitive. The bioluminescent method showed better accuracy than the chemiluminescent one (12.13% versus 21.50% mean standard deviation), even though both methods developed need improvements to ensure higher accuracy and become more reliable. A direct relation between both methods results was not possible to establish as while the chemiluminescent method focuses more on the amounts of oxidizing material in the samples, the bioluminescent one assesses their toxicity. A sample may have higher values of oxidizing components, giving higher values with the chemical method, and produce less toxic effects than another with lower amount of oxidizing materials, not displaying so high results with the biological method as the second sample. We concluded that both methods can and should be used together, in order to obtain more valuable and complete information about the air pollution samples. |
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