Direct Determination of Copper in Biodiesel Using Stripping Analysis

Almeida, Eduardo Santos; Monteiro, Marina A. N. A.; Montes, Rafael Marangoni; Mosquetta, Rafael; Coelho, Nívia M. M.; Richter, Eduardo M.; Muñoz, Rodrigo A.A.

doi:10.1002/elan.201000162

Cited by 39 publications

(22 citation statements)

References 24 publications

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“…This method was validated and demonstrates similar performance to atomic absorption spectrometry methods applied to metal determination in lubricating oils and biodiesel [21][22][23][24]. Biodiesel samples (176 mg) were treated with a mixture of 2 mL HCl + H 2 O 2 (1:1 v/v) inside closed 15 mL polyethylene vessels, which were placed in an ultrasonic bath for 30 min.…”

Section: Determination Of Fe P S Zn and Tbhq In Biodieselmentioning

confidence: 99%

Storage stability and corrosive character of stabilised biodiesel exposed to carbon and galvanised steels

Fernandes

Montes

Almeida

et al. 2013

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h i g h l i g h t s " Galvanised and carbon steels have proven to be compatible with biodiesel. " Biodiesel properties were not affected for a storage time of 56 days. " Zinc release in non-stabilised biodiesel did not stimulate biodiesel deterioration. " TBHQ was rapidly consumed in the first days of the corrosion immersion test. " TBHQ acted as a corrosion inhibitor and enhanced storage stability of biodiesel. a b s t r a c tThe storage stability and corrosive character of soybean biodiesel stabilised with tert-butylhydroquinone (TBHQ) was investigated through static immersion corrosion tests. Coupons of carbon steel and galvanised steel were immersed in soybean biodiesel with and without TBHQ for 12 weeks. Measurements of total acid number, peroxide value, oxidation stability (Rancimat induction period), metal release, and TBHQ consumption at different stages of corrosion were performed. After 12 weeks of the static immersion test with both steels, the non-stabilised biodiesels presented induction times below the EN 14214 limit (6 h); these results were in agreement with increase in the peroxide values. Zinc release was only detected in the non-stabilised biodiesel exposed to galvanised steel, whilst iron was not detected in any biodiesel samples exposed to carbon steel. The absence of zinc in the TBHQ-doped biodiesel exposed to galvanised steel indicates that TBHQ may have acted as a corrosion inhibitor. Additionally, TBHQ was rapidly consumed in the first 3 days of experiments, providing evidence of its activity. For a storage period of up to 56 days, both galvanised and carbon steels were shown to be compatible with biodiesel even in the absence of an antioxidant. The presence of zinc (>2 lg g À1 after 28 days of immersion) due to corrosion did not promote biodiesel deterioration.

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Section: Determination Of Fe P S Zn and Tbhq In Biodieselmentioning

confidence: 99%

Storage stability and corrosive character of stabilised biodiesel exposed to carbon and galvanised steels

Fernandes

Montes

Almeida

et al. 2013

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“…These attractive characteristics have encouraged applications of electrochemical techniques in several areas such as biomedical analysis, industrial quality control and environmental monitoring. 2 Potentiometry [3][4][5] and potentiometric stripping methods, 6 the simplest electroanalytical techniques, have been successfully used for quantification of some metallic species in different samples. However, stripping voltammetry is by far the most used electrochemical technique for heavy metals quantification.…”

Section: Introductionmentioning

confidence: 99%

Fast and simultaneous determination of Pb2+ and Cu2+ in water samples using a solid paraffin-based carbon paste electrode chemically modified with 2-aminothiazole-silica-gel

Silva¹,

Costa²,

Takeuchi³

et al. 2011

J. Braz. Chem. Soc.

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Um eletrodo de pasta de carbono preparado com parafina sólida como aglutinante e quimicamente modificado com sílica funcionalizada com grupos 2-aminotiazol foi empregado na quantificação simultânea de Pb 2+ e Cu 2+ em amostras de água por meio de voltametria de redissolução anódica. O presente método emprega um tempo curto de pré-concentração (180 s), o qual permitiu a quantificação simultânea e confiável de Pb 2+ e Cu 2+ de maneira bastante rápida. Foram obtidos limites de detecção de 7,3 e 90 nmol L −1 para Pb 2+ e Cu 2+ , respectivamente. Estes valores estão abaixo das concentrações máximas permitidas destes metais em água potável segundo a legislação brasileira, indicando que o método proposto é aplicável para o monitoramento de Pb 2+ e Cu 2+ em amostras de água. Estudos de recuperação foram realizados em quatro amostras de água enriquecidas, sendo obtidas porcentagens de recuperação próximas a 100% para todas as amostras analisadas, demonstrando a boa acuracidade do método proposto.A solid paraffin-based carbon paste electrode modified with 2-aminothiazole functionalized silica-gel was used for simultaneous quantification of Pb 2+ and Cu 2+ in water samples by anodic stripping voltammetry. The present method uses short preconcentration time (180 s), which allowed reliable and simultaneous quantification of Pb 2+ and Cu 2+ in a very fast way. Detection limits of 7.3 and 90 nmol L −1 were obtained for Pb 2+ and Cu 2+ , respectively. These values are below their maximum concentrations allowed in drinking water by Brazilian legislation, indicating that the proposed method is useful to monitoring Pb 2+ and Cu 2+ in water samples. Recovery studies were performed in four spiked water samples and the results shown recovery percentages close to 100% for all analyzed samples, demonstrating the good accuracy of the proposed method.Keywords: anodic stripping voltammetry, carbon paste electrode, 2-aminothiazolefunctionalized silica gel, lead and copper determination, water samples IntroductionEnvironmental contamination by heavy metals is a growing concern because they are very toxic, bioaccumulative and totally non-degradable. Therefore, environmental monitoring of heavy metals is of great importance for many reasons, such as identification of pollutant sources, understanding pollutant dissemination, anticipation of remediation procedures, etc. Copper and lead are two very important metallic pollutants because they are toxic and abundant. Contamination of natural waters by anthropogenic activities is one of the main ways to introduce heavy metals in the environment. Therefore, quantification of metallic ions in water samples is very important in order to preserve safe water resources for world population. In all regions around the world, legislative instruments are very restrictive regarding copper and lead contents in water for human consumption. In Brazil, for example, limits for Pb 2+ and Cu 2+ in drinking water are 0.01 mg L −1 (48 nmol L −1 ) and 2 mg L −1 (31 μmol L −1 ) , respectively. 1 Graphite furnace ato...

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“…The calibration graph covered the concentration range of 1-40 ppb, and the method was successfully employed for determination of sulfur in ethanol. Almeida et al [139] have presented the only work in which a stripping-based method is used to analyze biodiesel samples. These authors have used constant current potentiometric stripping at a gold electrode to determine Cu 2+ in biodiesel.…”

Section: Wwwintechopencommentioning

confidence: 99%

“…A more convenient peak-shaped response for analytical purposes is obtained by plotting dt/dE vs. E which produces analytical signs in form of www.intechopen.com peaks which are more convenient. The constant current PSA method used by Almeida et al [139] has allowed the determination of Cu 2+ in biodiesel without sample decomposition. The analyses were performed after a simple dilution of biodiesel samples in a mixture ethanolHCl aqueous solution, producing a homogeneous mixture in which Cu 2+ was directly quantified.…”

Section: Wwwintechopencommentioning

confidence: 99%