Review of procedures involving separation and preconcentration for the determination of cadmium using spectrometric techniques (original) (raw)
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Revista Virtual de Química, 2018
This paper reports an environmentally friendly analytical technique by extraction and pre-concentration of metal ions in cloud point for increased sensitivity and replacement of toxic solvents. The cloud point extraction (CPE) proved to be an easy, cheap, efficient and safe method for pre-concentrate trace metals. Cadmium and nickel were extracted simultaneously using complexes of dithiocarbamate in acidic medium, and quantitatively extracted with surfactant Triton X-114 and determined by atomic absorption spectrophotometry (AAS). Under optimal conditions, the limits of quantification (LQ) were 4,92 µg L-1 for Cd and 17,4 µg L-1 for Ni. The proposed method was applied to the quantification of cadmium and nickel in water sample, with satisfactory results.
Evaluation of laser induced breakdown spectroscopy for cadmium determination in soils
Spectrochimica Acta Part B-atomic Spectroscopy, 2009
This paper aims to present the didactic-pedagogic potential of Kodu Game Lab, an educational software constructionist, where students can learn the concepts of logical reasoning, and playing with many objects in a three dimensional environment elements and multimedia, as an alternative to traditional instructional method. Resumo. Este trabalho tem como objetivo apresentar o potencial didáticopedagógico do Kodu Game Lab, um software educativo construcionista, onde o aluno pode aprender conceitos de raciocínio lógico, jogando com objetos e vários elementos num ambiente tridimensional e multimídia, como alternativa ao método tradicional instrucionista.
DETERMINATION OF Cd AND Pb IN XANTHAN GUM SAMPLES BY GF AAS
Química Nova, 2014
DETERMINATION OF Cd AND Pb IN XANTHAN GUM SAMPLES BY GF AAS. This paper describes the evaluation of a method for determination of Cd and Pb in xanthan gum samples by Graphite Furnace Atomic Absorption Spectrometry (GF AAS) using NH 4 H 2 PO 4 as the chemical modifier. The sample preparation was performed using a reflux system adapted in the digestion tubes. With this system it was possible to increase the temperature of the digester block above the boiling point of the reaction medium, preventing loss of analyte and excessive evaporation of acids during heating. Samples were digested with HNO 3 for 3 h in a digester block at 220 °C. The limits of detection for Cd and Pb were 2.2 and 33.8 ng g-1 , respectively. The RSDs for both analytes were, on average, lower than 5.0% and accuracy was verified by recovery tests, yielding values in the 83-100% range.
Sequential fractionation of cadmium and lead in soils
Ciência Rural
The hazard environment impact and soil pollution by heavy metals should be evaluated not only by total concentration but mainly by their bioavailability because this property is better related with plant uptake. The objective of this experiment was to evaluate, trough sequential chemical extractions, the bioavailability of cadmium and lead in six soils of Rio Grande do Sul State, Brazil. The soil samples investigated come from a long term experiment in which 10 years ago three levels of Cd and Pb were applied (1.25, 2.50 and 5.0mg Cd and 250, 500, 1000mg Pb kg-1 soil). The sequential extractions detected differences among the adsorption forms of the two metals in the soils. The Cd was detected in all fractions, mainly in the exchangeable and organic, while Pb concentrated on the organic and residual fractions. The Cd presented larger mobility in soils, especially in those with smaller clay content; mobility of lead was very low in all soils.
2015
Phytoremediation is a technique that uses plants for decontaminating polluted areas, as soil and water, especially from heavy metals and organic contaminants, reducing their concentration to safe levels. In addition, it contributes to improve physical, chemical and biological characteristics of these areas. Among the several forms of environmental contamination resulted from industrial and agricultural activities, water contamination with heavy metals has been the one causing more concern to researchers and government institutions involved to pollution control. Cadmium (Cd) is one of the heavy metals more studied due to its high toxicity to plants and animals. In response to the stress caused by Cd, plants can develop many tolerance mechanisms which can operate sometimes as additional mechanisms. Two possible mechanisms can be the activation of the antioxidant system and/or changes in sulfur metabolism, specially glutathione, an essential substrate to phytochelatins (PC) biosynthesi...
Assessment of Toxicity of Cadmium and Lead in Tomato
Eclética Química Journal
Having the objective of evaluating the effect of application of cadmium and lead in tomato in the content, rate of growth and translocation in different parts of the plant, tomato plants were grown in nutrient solution of Clark and submitted to rising doses of Pb: 0; 0,25; 1,0; 5,0 and 10,0 mg L-1. Cadmium translocated 21,9% to more than lead to the aerial part showing Pb concentrated in the roots while in the fruits, the translocation of these metals reached 1,89% for Cd and 1,38% for Pb. In relation to the control treatment, the fruits production was reduced from the concentration 5,0 mg L-1 de Pb and 1,0 mg L-1 of Cd.
Phosphorus application for the chemical immobilization of cadmium in contaminated soil
Química Nova
Recebido em 16/3/09; aceito em 19/2/10; publicado na web em 10/6/10 PHOSPHORUS APPLICATION FOR THE CHEMICAL IMMOBILIZATION OF CADMIUM IN CONTAMINATED SOIL. The objective of the study was to evaluate the effect of phosphorus on the Cd availability to plants of a contaminated soil using 109 Cd isotope and chemical extractants. The experiment was set in a randomized block design and the soil was labeled with 222 KBq of 109 Cd per pot and received 5 rates of P as triple superphosphate, growing lettuce plants as test crop. The use of phosphorus reduced pH of soil which altered the Cd availability in DTPA and Mehlich extractants. The lettuce Cd content decreased but its accumulation and L value increased in all treatments compared to the control, demonstrating the inefficiency of phosphorus in reducing the Cd availability.
Monitoring / bioaccumulation of cadmium by fontinalis antipyretica (aquatic moss)
The purpose of this study is to understand quantitatively and qualitatively the accumulation and release of Cd (II) in aqueous solution by aquatic bryophytes -Fontinalis antipyretica -as in rivers biomonitoring as in the decontamination of industrial effluents . The cadmium accumulation and subsequent elimination by moss was studied in laboratory by exposing plants to different concentrations of metal in the range 0.5 -2.5 mg l -1 for a contamination period of 144 h and then exposed to water free of metal during a decontamination of 192 h. A first order mass transfer kinetic model was fitted to experimental data.
Química Nova, 2018
PRECONCENTRATION BASED ON COPRECIPITATION USING SILVER CHROMATE AS A CARRIER FOR COPPER DETERMINATION BY FAAS. In the present paper, a preconcentration procedure based in the coprecipitation of copper by silver dichromate (Ag 2 CrO 4) and consecutive determination by flame atomic absorption spectrometry (FAAS) was proposed. The experimental factors were optimized from application of the Doehlert matrix and the conditions set: chromate concentration 5.8 × 10-4 mol L-1 , silver concentration 1.1 × 10-3 mol L-1 , pH 7.3 and disperser concentration HNO 3 0.38 mol L-1. Under these conditions, analytical parameters of the procedure were obtained, with the quantification limits of 0.76 μg L-1 , precision (based in the relative standard deviation, RSD %) with values lower than 2.7%, and preconcentration factor of 28. The accuracy of the procedure was given by addition/recovery test in water samples groundwater and mineral, and by comparison with results obtained by ICP-MS. The procedure developed presented be simple, sensitive and low cost, thus can be applied in the preconcentration and determination of copper in several water samples.