Estratégias analíticas para determinação de fósforo por espectrometria de absorção atômica com fonte contínua de alta resolução
Carregando...
Data
2008-02-18
Autores
Ferreira, Roberta Borges [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Foi desenvolvido um método para a determinação espectrométrica de fósforo em insumos agroindustriais. O método está baseado na determinação por Espectrometria de Absorção atômica com Fonte Contínua de Alta Resolução (HR-CS AAS) utilizando a linha atômica 213,618 nm e bandas de 246,400 nm e 324,616 nm. Foram estudadas as melhores condições para a análise via absorção pelas bandas de PO e da linha de P atômica. Para a primeira, a melhor forma de análise foi utilizar a chama oxidante ar / acetileno, já para a última situação a atomização foi pela utilização de uma chama oxidante de acetileno / óxido nitroso. As melhores condições de funcionamento, tais como altura do queimador, fluxo de gases e taxa de aspiração da amostra foram definidas, sendo seus valores ideais para cada comprimento de onda respectivamente: 246,400 nm (9 mm – 0,186 – 5 mL min-1), para 324,616 nm (8 mm – 0,170 – 5 mL min-1) e de 213,618 nm (4 mm – 0,450 – 5 mL min-1). Boa linearidade foinobtida para o intervalo de concentração 250 – 4000 mg L-1 P usando o modo de integração do sinal de absorbância CP ± 2 (5 pixels), utilizando-se os sais Na2HPO3.5H2O, NaH2PO4, NH4H2PO4 e H3PO4. Os resultados mostraram que era irrelevante a natureza dos compostos para obter um padrão de P. Quatro diferentes modos de integração de absorbância foram avaliados: CP ± 1 (3 pixels), CP ± 2 (5 pixels), CP ± 3 (7 pixels) e CP ± 4 (9 pixels). Foi observado que a sensibilidade (inclinação da curva e massa característica) melhoraram com o aumento do número de pixels. O método de determinação de P pelo HR-CS FAAS em insumos agroindustriais foi comparada com a titulação. A exatidão e precisão foram de acordo com 95% de confiança, o desvio padrão relativo (RSD) obtido foi de 2,0%. Boas recuperações, cerca de 98%, foi obtida a partir de testes de adição e recuperação.
It was developed a method for spectrometry determination of phosphorus in agroindustrial products. The method is based on the determination by high-resolution continuum source flame atomic absorption spectrometry technique (HR-CS FAAS) using the atomic line 213,618 nm and bands of 246,400 nm and 324,616 nm. It was studied the best conditions for the analysis, for the absorption by bands of PO and the line of P atomic. To the first the best form of analysis would be using an oxidizing air/acetylene flame for analyte atomization and the last an oxidizing acetylene/nitrous oxide flame. The best operating conditions was defined as the burner high, the gas flow rate and aspiration rate of the sample. The values for these operations conditions are respectively: to 246,400 nm ( 9 mm – 0,186 – 5 mL min-1), to 324,616 nm ( 8 mm – 0,170 - 5 mL min-1) and to 213,618 nm ( 4 mm – 0,450 - 5 mL min-1). Good linearity was obtained for the concentration range 250 – 4000 mg L-1 P using the wavelength integrate absorbance in CP ± 2 (5 pixels), using the salts Na2HPO3.5H2O, NaH2PO4, NH4H2PO4 e H3PO4. The results showed that the was irrelevant to the nature of the compound to obtain a standard of P. Four different wavelength integrated absorbance were evaluated: CP ± 1 (3 pixels), CP ± 2 (5 pixels), CP ± 3 (7 pixels) and CP ± 4 (9 pixels). It was observed that the sensitivity (slope and characteristic mass) improved with increased number of pixels. The method of analysis of P by HR-CS FAAS in agroindustrial products was compared with the titration. The accuracy and precision was agreement at 95% confidence level, the relative standard deviation (RSD) obtaneid was 2,0%. Good recoveries, about 98%, was obtained using test of addition and recovery.
It was developed a method for spectrometry determination of phosphorus in agroindustrial products. The method is based on the determination by high-resolution continuum source flame atomic absorption spectrometry technique (HR-CS FAAS) using the atomic line 213,618 nm and bands of 246,400 nm and 324,616 nm. It was studied the best conditions for the analysis, for the absorption by bands of PO and the line of P atomic. To the first the best form of analysis would be using an oxidizing air/acetylene flame for analyte atomization and the last an oxidizing acetylene/nitrous oxide flame. The best operating conditions was defined as the burner high, the gas flow rate and aspiration rate of the sample. The values for these operations conditions are respectively: to 246,400 nm ( 9 mm – 0,186 – 5 mL min-1), to 324,616 nm ( 8 mm – 0,170 - 5 mL min-1) and to 213,618 nm ( 4 mm – 0,450 - 5 mL min-1). Good linearity was obtained for the concentration range 250 – 4000 mg L-1 P using the wavelength integrate absorbance in CP ± 2 (5 pixels), using the salts Na2HPO3.5H2O, NaH2PO4, NH4H2PO4 e H3PO4. The results showed that the was irrelevant to the nature of the compound to obtain a standard of P. Four different wavelength integrated absorbance were evaluated: CP ± 1 (3 pixels), CP ± 2 (5 pixels), CP ± 3 (7 pixels) and CP ± 4 (9 pixels). It was observed that the sensitivity (slope and characteristic mass) improved with increased number of pixels. The method of analysis of P by HR-CS FAAS in agroindustrial products was compared with the titration. The accuracy and precision was agreement at 95% confidence level, the relative standard deviation (RSD) obtaneid was 2,0%. Good recoveries, about 98%, was obtained using test of addition and recovery.
Descrição
Palavras-chave
Quimica analitica, Fosfitos, Analytical chemistry
Como citar
FERREIRA, Roberta Borges. Estratégias analíticas para determinação de fósforo por espectrometria de absorção atômica com fonte contínua de alta resolução. 2009. 65 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Química, 2009.