Organic sulfur oxidation to sulfate in soil samples for total sulfur determination by turbidimetry

Rossete, Alexssandra Luiza Rodrigues Molina; Bendassolli, José Albertino

doi:10.1590/s0100-06832008000600031

Cited by 11 publications

(8 citation statements)

References 4 publications

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“…Different soil types with sandy and clayey texture, were used to evaluate the total S determination method (Rossete et al, 2008a). Soil samples were collected from the surface horizon (0-20 cm), at different locations in the State of São Paulo.…”

Section: Sample Preparation and Total Sulfur Determination In Soilmentioning

confidence: 99%

“…The soils were classified according to the Brazilian Soils Classification System (Embrapa, 2006). Organic S in soil samples was oxidized to sulphate to determine S by dry-ash oxidation, using NaHCO 3 (alkaline medium) and Ag 2 O as oxidizing agents (Rossete et al, 2008a). The soil sample (5.0 g) and NaHCO 3 /Ag 2 O mixture (2.0/0.2 g) were mixed in a porcelain mortar.…”

Section: Sample Preparation and Total Sulfur Determination In Soilmentioning

confidence: 99%

“…The conversion of organic S to sulphate by various methods was described elsewhere (Krouse et al, 1996;Menegário et al, 1998;Rossete et al, 2008a), but the complexity of the organic matrix of the soil hampers the procedures of sample preparation for isotope analysis of S. Most methods employed for sulfur oxidation in soil analysis involve wet or dry-ash oxidation (Rossete et al, 2008a). In comparison with wet oxidation, digestion by nitric and perchloric acids is more frequently used, but requires safety measures against explosion and fire, aside from possible material losses, that can make the method unserviceable (Tabatabai, 1982).…”

Section: Introductionmentioning

confidence: 99%

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Isotope determination of sulfur by mass spectrometry in soil samples

Rossete¹,

Carneiro²,

Filho³

et al. 2012

Rev. Bras. Ciênc. Solo

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SUMMARYSulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes ( 32 S, 33 S, 34 S, and 36 S) with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS) in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO 4 2-), which was determined by dry combustion with alkaline oxidizing agents. The total S-SO 4 2-concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO 2 gas, BaSO 4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO 3 . The isotope determination of S (atom % 34 S atoms) was carried out by isotope ratio mass spectrometry (IRMS). In this work, the labeled material (K 2 34 SO 4 ) was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.Index terms: sample preparation, soil samples, isotopic dilution, labeled material, stable isotope, 34 S. RESUMO: DETERMINAÇÃO ISOTÓPICA DE ENXOFRE POR ESPECTROMETRIA DE MASSAS (IRMS) EM AMOSTRAS DE SOLO

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Section: Sample Preparation and Total Sulfur Determination In Soilmentioning

confidence: 99%

Section: Sample Preparation and Total Sulfur Determination In Soilmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Isotope determination of sulfur by mass spectrometry in soil samples

Rossete¹,

Carneiro²,

Filho³

et al. 2012

Rev. Bras. Ciênc. Solo

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“…The turbidimetric analysis is widely used in the determination of sulfates in several types of matrices, such as plants (Rossete et al, 2011), soil (Rossete et al, 2008) and fertilizers (Vicente et al, 2001). …”

Section: Introductionmentioning

confidence: 99%

Optimization of a Microwave Assisted Extraction of Organic Sulphur from Domestic Sewage Sludge by UV-Vis Spectrophotometry Determination

Silva¹,

Rezende²

2017

JAS

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An alternative method for microwave-assisted extraction of organic sulphur in sewage sludge samples was optimized based on response surface methodology. The extraction process was defined by a 2 3 factorial design. In the factorial design, the temperature, the extraction time and the volume of hydrochloric acid in the solvent mixture were evaluated. The samples were extracted with a mixture of nitric acid and hydrochloric acid. The data obtained for study were based on the concentration of sulphur in the sulfate form (S-SO 4 2-) obtained spectrophotometrically in the sludge samples. The initial extraction parameters were adjusted so that spectrophotometric determination was feasible. According to the levels (minimum and maximum) defined for each parameter, the methodology showed that the best extraction conditions were achieved with an extraction temperature of 150 °C, using a longer extraction time (40 min). This study was carried out to evaluate the efficiency of microwave-assisted extraction in spectrophotometric determination of sulphur in sludge samples.

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“…9 Rossete et al 10 descreveram um método para oxidação em amostras de solo, em mufla por 8 h à temperatura de 550 ºC, na presença de agente oxidante (Ag 2 O) em meio alcalino (NaHCO 3 ). A quantificação do sulfato foi realizada pelo método turbidimétrico com a utilização de cloreto de bário e detecção espectrofotométrica, sendo este o mais explorado.…”

Section: Introductionunclassified

Determinação de enxofre em amostras vegetais por oxidação via seca em meio alcalino com detecção espectrofométrica

Rossete¹,

Carneiro²,

Batagello³

et al. 2011

Quím. Nova

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Recebido em 18/3/10; aceito em 2/8/10; publicado na web em 30/11/10 ESPECTROFOTOMETRIC DETERMINATION OF SULFUR IN PLANTS USING DRY ASH OXIDATION AND ALKALINE OXIDIZERS. The sulphur take an essential role in plants and it is one of the main nutrients in several metabolic processes. The dry ash oxidation, using alkaline oxidizers agent, is the simplest and most economical form for the oxidation of Organic S to sulfate in plants. The objective of this work is to propose a method for sulfur determination in plants samples using dry ash oxidation and agent oxidizers alkaline. The quantification of S-SO 4 2-in samples was accomplished by turbidimetric method. The results demonstrated that the proposed method for oxidation alkaline was appropriate.Keywords: sulfate; digestion; turbidimetric method. INTRODUÇÃOO enxofre tem papel essencial no metabolismo das plantas destacando-se como um dos principais nutrientes, principalmente no desempenho das funções vitais. O nutriente é necessário para o desenvolvimento das raízes, para a plena fotossíntese, estimulando a nodulação e a fixação do nitrogênio nas raízes das leguminosas, garantindo um crescimento mais vigoroso e incrementando a produção de sementes. [1][2][3][4][5] Embora até pouco tempo não se tenha dado muita importância a estudos relacionados ao ciclo do enxofre em plantas, alguns trabalhos têm revelado a deficiência de enxofre em plantas cultivadas por todo o mundo e especialmente no Brasil, evidenciando a deficiência de enxofre no solo. 3,6 Desta forma, deve-se salientar a importância de se estabelecer métodos simples e eficientes na determinação de S-total, possibilitando estudos detalhados e definições mais precisas sobre a dinâmica do nutriente no sistema solo-planta.Com relação ao enxofre orgânico, presente nas amostras vegetais, existem várias formas para promover a oxidação do S-orgânico a sulfato. Os procedimentos mais empregados envolvem a oxidação via úmida, digestão ácida. A via úmida é o método mais utilizado, em que as amostras vegetais em presença de ácido nítrico e perclórico são aquecidas em bloco digestor à temperatura de 190 a 210 ºC.7,8 Este tipo de digestão requer cuidado, pois podem ocorrer explosões, fogo e perda de material, tornando-a inconveniente; além disso, deve-se salientar a dificuldade na aquisição de ácidos por muitas instituições.A oxidação via seca utilizando agentes alcalinos é uma das formas mais simples na conversão do S-orgânico a sulfato.9 Rossete et al. 10 descreveram um método para oxidação em amostras de solo, em mufla por 8 h à temperatura de 550 ºC, na presença de agente oxidante (Ag 2 O) em meio alcalino (NaHCO 3 ). A quantificação do sulfato foi realizada pelo método turbidimétrico com a utilização de cloreto de bário e detecção espectrofotométrica, sendo este o mais explorado. 8,9 Este trabalho teve como objetivo propor uma alternativa de um procedimento analítico simples e eficiente para a determinação de enxofre em amostras vegetais, utilizando oxidação alcalina e detecção espectrofotométrica. A utilização da p...

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Organic sulfur oxidation to sulfate in soil samples for total sulfur determination by turbidimetry

Cited by 11 publications

References 4 publications

Isotope determination of sulfur by mass spectrometry in soil samples

Isotope determination of sulfur by mass spectrometry in soil samples

Optimization of a Microwave Assisted Extraction of Organic Sulphur from Domestic Sewage Sludge by UV-Vis Spectrophotometry Determination

Determinação de enxofre em amostras vegetais por oxidação via seca em meio alcalino com detecção espectrofométrica

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