Resumos
O trabalho em aprêço, relata o estudo de diversos aspectos do método espectrofotométrico da determinação do cobre pelo dietilditiocarbamato de sódio. Dentre os aspectos estudados, podem ser citados os seguintes: a) Reativo: influência da concentração e sua conservação em função do tempo. b) Influência da quantidade de EDTA. c) Solventes: escolha do solvente, do comprimento de onda e do filtro. d) Estabilidade do composto. e) Estudo da amplitude, exatidão e precisão do método. f) Aplicação do método, na determinação do cobre em plantas e solos.
A study is made on several aspects of the spectrophotometric method for the determination of copper by sodium diethyldithiocarbamate (DDC-Na). From this work could be observed that: a) The ideal amount of reagent a 1% of (DDC-Na) aqueous solution, was 1 ml and it was observed that the reagent keeps well until 40 days after its preparation. b) The absorbancy of the copper diethyldithiocarbamate (DDC-Na) solutions, to a certain limit is independent of the amounts of EDTA Na2. But, in the absence of EDTA-Na2 the amounts of copper added where not recovered, when working with pure solutions. c) Among the solvents used, carbon tetrachloride was considered the most appropriate. d) DDC-Cu in CCl4 shows maximum absorption in the wave lenght range 430-435 milimicrons. The greatest sensibility was obtained with filters numbers 42 and 44 (Klett-Summerson). e) Interferences of the ions studied were eliminate, by the use of EDTA-Na2 only. f) In this procedure, the DDC-Cu is stable until 45 minutes. g) The method obeys Beer's law in the range of 5-50 ppm, and shows good accuracy. h) The recommended procedures for the determinations of total copper both in plants and soils by the DDC-Na, are considered efficients.
A determinação do cobre pelo método calorimétrico do dietilditiocarbamato de sódio* * Resumo do trabalho apresentado pelo autor à E.S.A. "Luiz de Queiroz", como tese para obtenção do título de Doutor em Agronomia.
A.O. Jacintho
Cadeira de Química Analítica e Físico-Química da ESALQ
RESUMO
O trabalho em aprêço, relata o estudo de diversos aspectos do método espectrofotométrico da determinação do cobre pelo dietilditiocarbamato de sódio.
Dentre os aspectos estudados, podem ser citados os seguintes:
a) Reativo: influência da concentração e sua conservação em função do tempo.
b) Influência da quantidade de EDTA.
c) Solventes: escolha do solvente, do comprimento de onda e do filtro.
d) Estabilidade do composto.
e) Estudo da amplitude, exatidão e precisão do método.
f) Aplicação do método, na determinação do cobre em plantas e solos.
SUMMARY
A study is made on several aspects of the spectrophotometric method for the determination of copper by sodium diethyldithiocarbamate (DDC-Na).
From this work could be observed that:
a) The ideal amount of reagent a 1% of (DDC-Na) aqueous solution, was 1 ml and it was observed that the reagent keeps well until 40 days after its preparation.
b) The absorbancy of the copper diethyldithiocarbamate (DDC-Na) solutions, to a certain limit is independent of the amounts of EDTA Na2. But, in the absence of EDTA-Na2 the amounts of copper added where not recovered, when working with pure solutions.
c) Among the solvents used, carbon tetrachloride was considered the most appropriate.
d) DDC-Cu in CCl4 shows maximum absorption in the wave lenght range 430-435 milimicrons. The greatest sensibility was obtained with filters numbers 42 and 44 (Klett-Summerson).
e) Interferences of the ions studied were eliminate, by the use of EDTA-Na2 only.
f) In this procedure, the DDC-Cu is stable until 45 minutes.
g) The method obeys Beer's law in the range of 5-50 ppm, and shows good accuracy.
h) The recommended procedures for the determinations of total copper both in plants and soils by the DDC-Na, are considered efficients.
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LITERATURA CITADA
Entregue para publicação em 2/1/68.
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Datas de Publicação
-
Publicação nesta coleção
13 Jun 2012 -
Data do Fascículo
1967