Determinação simultânea de 'CD' e 'PB' e de 'CR' e 'NI' em plantas medicinais empregando a espectrometria de absorção atômica com amostragem direta de suspensões
Carregando...
Data
2013-02-26
Autores
Fortunato, Felipe Manfroi [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Esta dissertação versa sobre o desenvolvimento de métodos analíticos empregando a amostragem de suspensão na determinação simultânea de Cd e Pb e de Cr e Ni em plantas medicinais pela espectrometria de absorção atômica com forno de grafite. A utilização de Ir como modificador permanente possibilitou determinar Cd e Pb simultaneamente em suspensões 0,5% m/v de plantas medicinais empregando calibração com soluções aquosas. As temperaturas de pirólise e de atomização foram 1000°C e 2200°C, respectivamente. As massas caracteristicas foram 1,8 pg Cd e 59 pg Pb, limites de detecção de 0,024 μg g-1 Cd e 0,24 μg g-1 Pb e desvios padrão relativos da ordem de 5,3% (Cd) e 3,5% (Pb). Os resultados da análise de três materiais de referência certificados foram concordantes com os valores certificados ao nível de 95% de confiança (teste-t). Para determinação simultânea de Cr e Ni não foi necessário o uso de modificadores químicos e foram empregados suspensões 0,5% (m/v) e calibração aquosa. As temperaturas de pirólise e de atomização foram de 1600°C e 2300°C, respectivamente. As massas caracteristicas foram 5,8 pg Cr e 31 pg Ni e os limites de detecção 0,04 μg g-1 Cr e 0,3 μg g-1 Ni. Os desvios padrão relativos foram 2,8% e 2,2% para Cr e Ni, respectivamente. Quatro materiais de referência certificados de plantas foram analisados e os resultados foram concordantes com os teores certificados a 95% de confiança (teste-t). Dez plantas medicinais foram analisadas pelos métodos propostos e os teores dos analitos variaram de 0,19 a 0,34 μg g-1 Cd, 1,02 a 1,91 μg g-1 Pb, 1,73 a 11,6 μg g-1 Cr e 0,78 a 5,54 μg g-1 Ni. Estas concentrações estão compatíveis com as usualmente encontradas em plantas medicinais
This dissertation deals with the development of analytical methods employing slurry sampling in simultaneous determination of Cd and Pb, Cr and Ni in medicinal plants by graphite furnace atomic absorption spectrometry. Tue use of iridium with permanent modifier allowed simultaneous determination of Cd and Pb in 0.5% (m/v) slurries of medicinal plants using aqueous standards calibration. The pyrolysis and atomization temperatures were 1000°C and 2200°C, respectively. The characteristic masses were 1.8 pg Cd and 59 pg Pb, limits of detection were 0.024 μg g-1 Cd e 0.24 μg g-1 Pb and relative standard deviation the order of 5.3% (Cd) and 3.5% (Pb). Results obtained for analysis of three certified reference materials were in agreement with certified values at 95% confidence level (t-test). For simultaneous determination of Cr and Ni did not require chemical modifier and 0.5% (m/v) slurries and aqueous calibration were employed. Pyrolysis and atomization temperatures were 1600°C and 2300°C, respectively. The characteristic masses were 5.8 pg Cr and 31 pg Ni and the limits of detection 0,04 μg g-1 Cr e 0,3 μg g-1 Ni. The relative standard deviation were 2.8% and 2.2% for Cr and Ni, respectively. Four plant certified reference materials were analyzed and results were in agreement at a 95% confidence level (t-test) with certified values. Ten medicinal plant samples were analyzed by the proposed methods and found concentrations were in the range of 0.19 - 0.34 μg g-1 Cd, 1.76 - 11.60 μg g-1 Cr, 0.78 – 5.54 μg g-1 Ni and 1.02 - 1.91 μg g-1 Pb ranges. These levels are comparable to levels commonly found in medicinal plants
This dissertation deals with the development of analytical methods employing slurry sampling in simultaneous determination of Cd and Pb, Cr and Ni in medicinal plants by graphite furnace atomic absorption spectrometry. Tue use of iridium with permanent modifier allowed simultaneous determination of Cd and Pb in 0.5% (m/v) slurries of medicinal plants using aqueous standards calibration. The pyrolysis and atomization temperatures were 1000°C and 2200°C, respectively. The characteristic masses were 1.8 pg Cd and 59 pg Pb, limits of detection were 0.024 μg g-1 Cd e 0.24 μg g-1 Pb and relative standard deviation the order of 5.3% (Cd) and 3.5% (Pb). Results obtained for analysis of three certified reference materials were in agreement with certified values at 95% confidence level (t-test). For simultaneous determination of Cr and Ni did not require chemical modifier and 0.5% (m/v) slurries and aqueous calibration were employed. Pyrolysis and atomization temperatures were 1600°C and 2300°C, respectively. The characteristic masses were 5.8 pg Cr and 31 pg Ni and the limits of detection 0,04 μg g-1 Cr e 0,3 μg g-1 Ni. The relative standard deviation were 2.8% and 2.2% for Cr and Ni, respectively. Four plant certified reference materials were analyzed and results were in agreement at a 95% confidence level (t-test) with certified values. Ten medicinal plant samples were analyzed by the proposed methods and found concentrations were in the range of 0.19 - 0.34 μg g-1 Cd, 1.76 - 11.60 μg g-1 Cr, 0.78 – 5.54 μg g-1 Ni and 1.02 - 1.91 μg g-1 Pb ranges. These levels are comparable to levels commonly found in medicinal plants
Descrição
Palavras-chave
Quimica analitica, Plantas medicinais, Suspensão (Quimica), Medicinal plants
Como citar
FORTUNATO, Felipe Manfroi. Determinação simultânea de 'CD' e 'PB' e de 'CR' e 'NI' em plantas medicinais empregando a espectrometria de absorção atômica com amostragem direta de suspensões. 2013. 60 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Química, 2013.