Determination of phosphorus by graphite furnace atomic absorption spectrometry. Part 2. Comparison of different modifiers

Curtius, Adilson José; Schlemmer, Gerhard; Welz, Bernhard

doi:10.1039/ja9870200115

Cited by 40 publications

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“…The palladium and calcium mixed modifier was recommended for the determination of P more than 20 years ago, giving the best sensitivity for this analyte [19]. However, it was also found more recently, using HR-CS GF AAS that this modifier is producing significant continuous and structured background, which is causing interference when D 2 -BC is used [14].…”

Section: The Palladium and Calcium Mixed Modifiermentioning

confidence: 99%

Investigation of the feasibility to use Zeeman-effect background correction for the graphite furnace determination of phosphorus using high-resolution continuum source atomic absorption spectrometry as a diagnostic tool

Lepri

Welz

Dessuy

et al. 2010

Spectrochimica Acta Part B: Atomic Spectroscopy

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The determination of phosphorus by graphite furnace atomic absorption spectrometry at the non-resonance line at 213.6 nm, and the capability of Zeeman-effect background correction (Z-BC) to deal with the finestructured background absorption due to the PO molecule have been investigated in the presence of selected chemical modifiers. Two line source atomic absorption spectrometers, one with a longitudinally heated and the other with a transversely heated graphite tube atomizer have been used in this study, as well as two prototype high-resolution continuum source atomic absorption spectrometers, one of which had a longitudinally arranged magnet at the furnace. It has been found that Z-BC is capable correcting very well the background caused by the PO molecule, and also that of the NO molecule, which has been encountered when the Pd + Ca mixed modifier was used. Both spectra exhibited some Zeeman splitting, which, however, did not cause any artifacts or correction errors. The practical significance of this study is to confirm that accurate results can be obtained for the determination of phosphorus using Z-BC. The best sensitivity with a characteristic mass of m 0 = 11 ng P has been obtained with the pure Pd modifier, which also caused the lowest background level. The characteristic mass obtained with the mixed Pd+Ca modifier depended on the equipment used and was between m 0 = 9 ng P and m 0 = 15 ng P, and the background signal was higher. The major problem of Z-BC remains the relatively restricted linear working range.

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Section: The Palladium and Calcium Mixed Modifiermentioning

confidence: 99%

Investigation of the feasibility to use Zeeman-effect background correction for the graphite furnace determination of phosphorus using high-resolution continuum source atomic absorption spectrometry as a diagnostic tool

Lepri

Welz

Dessuy

et al. 2010

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…Este autor e colaboradores 19 investigaram o efeito de 9 metais sobre o sinal de fósforo, incluindo paládio e ferro em tubos de diferentes materiais: grafite eletrolítico, grafite eletrolítico recoberto com uma camada de grafite pirolítico com plataforma pirolítica e grafite recoberto, por deposição física de vapor, com carbeto de tântalo (TaC). As massas características (massa característica é a massa que produz uma absorvância de 0,0044s) não diferiram por mais do que um fator de 2, usando-se diferentes tubos para um mesmo modificador.…”

Section: Introductionunclassified

“…Lantânio tem um efeito bastante prejudicial à vida do tubo de grafite 19,20,21 sendo bastante corrosivo, assim como o ferro (III) 20 . Paládio mostrou-se superior ao lantânio e ao níquel, neste aspecto, permitindo mais de 440 queimas com um mesmo tubo sem prejuízo da sensibilidade e com desvio-padrão relativo inferior a 5% 19 .…”

Section: Introductionunclassified

“…Entre os modificadores, lantânio, ítrio e uma mistura de paládio com cálcio produziram o melhor valor de massa característica, 5,5 ng/0,0044 s, no tubo recoberto com uma camada pirolítica no qual foi inserida uma plataforma de grafite pirolítico. A sensibilidade, no entanto, varia com a massa do modificador aumentando com a mesma.Lantânio tem um efeito bastante prejudicial à vida do tubo de grafite 19,20,21 sendo bastante corrosivo, assim como o ferro (III) 20 . Paládio mostrou-se superior ao lantânio e ao níquel, neste aspecto, permitindo mais de 440 queimas com um mesmo tubo sem prejuízo da sensibilidade e com desvio-padrão relativo inferior a 5%…”

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Determinação de fósforo em aços por espectrometria de absorção atômica no forno de grafite

Curtius

1998

Quím. Nova

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steel samples by graphite furnace atomic absorption spectrometry, using the Zeeman effect background correction and the STPF conditions is proposed. The effect of iron (III) on the phosphorus signal was studied. It was verified, through the pyrolysis temperature curves, that iron (III) is an efficient chemical modifier, thermically stabilizing phosphorus up to 1400 o C. The phosphorus signal increases with the iron (III) concentration, but in the range, which corresponds to the usual concentrations of iron in the sample solutions, the increase is small. Phosphorus was determined in three standard reference materials, after its dissolution in a mixture of hydrochloric and perchloric acids in a PTFE bomb. The agreement with the certified concentration values was excellent. Iron (III) was added to the reference analytical solutions prepared in the blank of the dissolution, while the sample solutions were measured directly, since they already contained the modifier. The detection limit (k = 2) was 0.0042% of phosphorus in the steel sample.Keywords: graphite furnace atomic absorption spectrometry; steel; phosphorus. ARTIGO INTRODUÇÃOA espectrometria de absorção atômica no forno de grafite (GFAAS) é pouco utilizada na determinação de fósforo. Apenas quatro referências foram encontradas na literatura [1][2][3][4] , sobre a determinação de fósforo em aços e ligas, após dissolução ácida das amostras. Uma das razões, é que as linhas de ressonância para este elemento estão na região entre 167,2 e 178,8 nm, não utilizável em instrumentos convencionais, por causa da necessidade de vácuo ou purga com um gás inerte. L'vov e o C. Ainda assim, neste dublete, a sensibilidade é cerca de 100 vezes menor do que nas linhas de ressonância 6 . Além disso, Persson e Frech 7 observaram, através de cálculos teóricos e dados experimentais, perdas de fósforo antes da atomização, na forma de sub-óxidos e/ou moléculas do dímero de modo que para obter resultados reprodutíveis, recomendaram controle da temperatura final do forno e também da atmosfera dentro do tubo de grafite. Para diminuir as perdas e aumentar a sensibilidade, é importante a formação de uma fase termicamente estável. O grafite eletrolítico, mais ativo do que o pirolítico, e principalmente ativado com gás oxigênio, é capaz de estabilizar o fós-foro, conforme verificado por este autor e colaboradores 8 . No entanto, ainda assim, grandes quantidades de fósforo são perdidas antes da atomização, de modo que uma determinação sem um modificador químico não tem importância prática. Ediger 9 propôs o uso de lantânio como modificador para fósfo-ro, que foi usado em algumas aplicações analíticas 4,10-12 . Ní-quel também foi usado como modificador 3,13 , já que havia se mostrado eficiente na determinação do análogo arsênio 14,15 . Saeed e Thomassen 16 listaram 21 elementos que melhoram a sensibilidade do fósforo, mas os dados foram baseados em altura de pico, não refletindo, portanto, a eficiência da atomização. A modificação da superfície do tubo de grafite com zircônio também foi propos...

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“…The soil pH was measured via an INESA pH meter (Shanghai REX Instrument Factory, Shanghai, China) in a 1:5 suspension of ultrapure water. The TP content was measured using the ammonium molybdate spectrometry method (Curtius et al 1987). TK content via the method was introduced in the book Soil agricultural chemistry analysis (Bao 2000).…”

Section: Soil Physicochemical Analysismentioning

confidence: 99%

Oilseed rape cultivation increases the microbial richness and diversity in soils contaminated with cadmium

et al. 2018

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Purpose This investigation aimed to estimate and characterize the microbial diversity in soils with cadmium (Cd) at different concentrations and to evaluate whether Brassica napus can restore the soil microbial diversity. Materials and methods We conducted the pot experiment to analyze the composition of microbial communities in the soil contaminated with 0, 1, and 2 mg/kg Cd, as well as planted with oilseed rape. The bacterial and fungal communities were characterized via next-generation sequencing based on 16S and 18S rRNA gene fragments pyrosequencing, respectively. Results and discussion The results show that cadmium contamination decreased both the microbial richness and diversity in the soil, while the cultivation of oilseed rape increased the richness and diversity. In bacteria, Proteobacteria was the most abundant phylum in all the samples accounting for 39.62 to 46.14%, followed by Bacteroidetes, Actinobacteria, and Chloroflexi. These phyla collectively comprised more than 70% of all phyla. Ascomycota was the most abundant phylum in all samples in fungi (89.65 to 96.00%), and it was the only phylum whose abundance was increased with the rise of Cd concentration. Conclusions Microbial richness and diversity were affected by the combined action of Cd and B. napus. Cd contamination decreased the microbial richness and diversity, while cropping with oilseed rape increased the microbial richness and diversity, which alleviated the deleterious effect of the Cd pollution in soils. These reflected that oilseed rape played a positive role in maintaining species diversity of microorganism from the side.

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Determination of phosphorus by graphite furnace atomic absorption spectrometry. Part 2. Comparison of different modifiers

Cited by 40 publications

References 0 publications

Investigation of the feasibility to use Zeeman-effect background correction for the graphite furnace determination of phosphorus using high-resolution continuum source atomic absorption spectrometry as a diagnostic tool

Investigation of the feasibility to use Zeeman-effect background correction for the graphite furnace determination of phosphorus using high-resolution continuum source atomic absorption spectrometry as a diagnostic tool

Determinação de fósforo em aços por espectrometria de absorção atômica no forno de grafite

Oilseed rape cultivation increases the microbial richness and diversity in soils contaminated with cadmium

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