Comparative study of electrothermal atomic absorption spectrometric methods for the determination of silver in used lubricating oils

Aucélio, Ricardo Q.; Curtius, Adilson José

doi:10.1039/b004059m

Cited by 37 publications

(25 citation statements)

References 41 publications

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“…The use of platforms of L'vov covered with carbide forming elements (Zr, W, La and Nb) [10,11,12,13,14,15,16,17], and more recently tubes or platforms covered with platinum group element modifiers (Pd, Pt, Ir, Rh and Ru) [18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36] have been studied as chemical modifiers in direct determinations of metals in the graphite furnace. Surfaces such as these have the advantage of acting as a permanent chemical modifier, allowing a great number of atomization cycles without the necessity for new applications of the modifier, besides making possible the in situ cleaning of the modifier during the deposition stage.…”

Section: Kátia Linces Alves Lelis · Cristina Gonçalves Magalhães · CLmentioning

confidence: 99%

Direct determination of Cr and Cu in urine samples by electrothermal atomic absorption spectrometry using ruthenium as permanent modifier (R1)

Lelis¹,

Magalhães

Rocha³

et al. 2002

Anal Bioanal Chem

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In this study Ru, deposited thermally on an integrated platform pyrolytic graphite tube, is proposed as a permanent modifier for the determination of Cu and Cr in urine samples by electrothermal atomic absorption spectrometry. The samples were diluted 1:1 with nitric acid (1% v/v). Pyrolysis and atomization temperatures for spiked urine samples were 1,100 degrees C and 1,900 degrees C respectively for Cu, and 1,400 degrees C and 2,500 degrees C respectively for Cr. For comparison purposes, the conventional modification with Pd+Mg was also studied. The sensitivity for Ru as permanent modifier was higher for the two analytes. The characteristic masses were 7.3 and 17.7 for Cr and Cu. The detection limits (3sigma) were 0.22 and 0.32 microg/L, for Cr and Cu, respectively. Good agreement was obtained with certified urine samples for the two elements.

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Section: Kátia Linces Alves Lelis · Cristina Gonçalves Magalhães · CLmentioning

confidence: 99%

Direct determination of Cr and Cu in urine samples by electrothermal atomic absorption spectrometry using ruthenium as permanent modifier (R1)

Lelis¹,

Magalhães

Rocha³

et al. 2002

Anal Bioanal Chem

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“…33 About 0.1 g of the sample or base mineral oil (in case of the blank) was dissolved in 2.0 mL of xylene to reduce the viscosity. An aliquot of 0.5 mL of concentrated nitric acid was added and the mixture placed in an ultrasonic bath for 5 min.…”

Section: Preparation Of Microemulsionsmentioning

confidence: 99%

Methods for vanadium determination in fuel oil by GF AAS with microemulsification and acid digestion sampling

Amorim

Lima

Amaro

et al. 2007

J. Braz. Chem. Soc.

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Dois métodos para determinação de vanádio em óleo combustível são propostos utilizando GF AAS. O primeiro é baseado na preparação de uma microemulsão da amostra que é diretamente injetada no tubo de grafite. As temperaturas de pirólise e atomização, 1500 e 2700 °C, respectivamente, foram otimizadas a partir das curvas de temperatura. Para este procedimento obteve-se um limite de detecção de 0,10 μg g -1 e uma massa característica de 87 pg. O outro método utiliza digestão da amostra com ácido sulfúrico, ácido nítrico e peróxido de hidrogênio. As temperaturas de pirólise e atomização, otimizadas, foram 1000 e 2700 °C, respectivamente. Para este procedimento, obteve-se um limite de detecção de 0,25 μg g -1 e uma massa característica de 63 pg. A exatidão de ambos os métodos foi confirmada pela análise do material de referência certificado NIST SRM 1634c-trace metals in fuel oil.Two methods for vanadium determination in fuel oil are proposed using GF AAS. The first is based on the preparation of a microemulsion followed by direct injection into the graphite tube. The pyrolysis and atomization temperatures, 1500 and 2700 °C, respectively, were chosen from the temperature curves. This procedure allows determination of vanadium with a detection limit of 0.10 μg g -1 and characteristic mass of 87 pg. The other method uses total acid digestion of the sample with sulfuric acid, nitric acid and hydrogen peroxide. In this procedure, the pyrolysis and atomization temperatures recommended were 1000 and 2700 °C, respectively. Among the analytical characteristics for this method are a detection limit of 0.25 μg g -1 and a characteristic mass of 63 pg. The accuracy of both procedures was confirmed by the determination of vanadium in the certified reference material NIST SRM 1634c-trace metals in fuel oil.Keywords: vanadium, fuel oil, microemulsion, digestion sample, GF AAS IntroductionThe determination of metals and non-metals in petroleum and its derivatives is of great interest regarding the quality of oil and for environmental aspects. The most difficult part is usually the sample preparation, the most reliable procedure being ashing of the sample and analysis of the residue after taking up in hydrochloric acid. 1 However, this procedure is quite tedious and requires careful control to avoid analyte losses, and even microwave-assisted digestion procedures require relatively long time. 2 Graphite Furnace Atomic Absorption Spectrometry (GF AAS) is offering advantages over other techniques since the results from a simple dilution with an organic solvent and ashing were found to be practically identical. 3,4 However, stability of metal concentration in sample and calibration solutions might become a serious problem 1567 Amorim et al. Vol. 18, No. 8, 2007 under these conditions. 5,6 The formation and analysis of an oil-in-water emulsion or microemulsion instead of a dilution of the oil sample with an organic solvent has been proposed to avoid this problem. [7][8][9][10][11] Fuel oil is a highly viscous residual fraction of petrol...

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“…Also calibration is a problem, because standard solutions prepared in aqueous medium usually do not compensate for the non-spectral interferences. 28,29 The conventional sample treatment normally involves digestion. Wet digestion of sample with a high organic content may include calcinations at high temperature and the use of an acid mixture.…”

Section: Introductionmentioning

confidence: 99%

Calibration techniques and modifiers for the determination of Cd, Pb and Tl in biodiesel as microemulsion by graphite furnace atomic absorption spectrometry

Silva¹,

Chaves²,

Santos³

et al. 2010

J. Braz. Chem. Soc.

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Diferentes calibrações e modificadores foram testados para a determinação de Cd, Pb e Tl em biodiesel por espectrometria de absorção atômica em forno de grafite (GF AAS). Foram preparadas microemulsões usando-se 2 g de biodiesel, 1 mL de solução aquosa de ácido nítrico 10% (v/v) e n-propanol até o volume final de 10 mL. As temperaturas de pirólise foram: 600 °C para Cd e Tl com Pd como modificador permanente e 800 °C para Pb com Ru como modificador permanente. As temperaturas de atomização também foram otimizadas. A calibração aquosa não corrigiu as interferências não espectrais, mas a calibração com simulação de matriz produziu resultados exatos com recuperações entre 80 e 116%. Os valores de RSD foram menores do que 8% para e Cd e Pb com valores de LOD de 0,5 ng g -1 para Cd, 6 ng g -1 para Pb e 1 ng g -1 para Tl. Os resultados obtidos usando-se calibração pelo método de adições de analito e por simulação de matriz foram concordantes. Padrões organometálicos não foram necessários. Diferentes amostras de biodiesel foram analisadas.Different calibration approaches and modifiers were tested for Cd, Pb and Tl determination in biodiesel by graphite furnace atomic absorption spectrometry (GF AAS). Microemulsions were prepared by mixing 2 g of biodiesel, 1 mL of a 10% (v/v) nitric acid aqueous solution and n-propanol to a 10 mL final volume. Pyrolysis temperatures of 600 °C for Cd and Tl with Pd as permanent modifier, and 800 °C for Pb with Ru as permanent modifier were used. Atomization temperatures were also optimized. Calibration solution prepared in aqueous medium did not correct non-spectral interferences, but matrix matching calibration using base oil led to accurate results with recoveries from 80 to 116%. The RSD values were lower than 8% for Cd and Pb and the LOD values were 0.5 ng g -1 for Cd, 6 ng g -1 for Pb and 1 ng g -1 for Tl. The obtained results using the analyte additions method or by matrix matching calibration were in agreement, confirming the accuracy of the proposed procedure. Organometallic standards were not required and different samples were analyzed.

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Comparative study of electrothermal atomic absorption spectrometric methods for the determination of silver in used lubricating oils

Cited by 37 publications

References 41 publications

Direct determination of Cr and Cu in urine samples by electrothermal atomic absorption spectrometry using ruthenium as permanent modifier (R1)

Direct determination of Cr and Cu in urine samples by electrothermal atomic absorption spectrometry using ruthenium as permanent modifier (R1)

Methods for vanadium determination in fuel oil by GF AAS with microemulsification and acid digestion sampling

Calibration techniques and modifiers for the determination of Cd, Pb and Tl in biodiesel as microemulsion by graphite furnace atomic absorption spectrometry

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