Determination of iron in alkaline salts by ICP-AES using 1-(2-Thiazolylazo)-p-cresol (TAC) for preconcentration and separation

Abstract

O presente trabalho descreve o uso de 1-(2-thiazolylazo)-p-cresol (TAC) para separação, preconcentração e determinação de traços de ferro (ng g -1 ) em sais alcalinos usando a técnica ICP-AES. O método proposto é baseado na extração líquido-líquido do complexo formado entre o cátion ferro(III) e o 1-(2-thiazolylazo)-p-cresol (TAC). Foram estudados parâmetros tais como: quantidade de TAC, efeito de pH, influência do solvente orgânico, mineralização da fase orgânica e re-extração. Os resultados demonstraram que o complexo ferro(III)-TAC, formado na faixa de pH de 4,0 a 10,0, pode ser quantitativamente extraído de soluções salinas, usando como solvente extractor álcool isoamílico, tetracloreto de carbono, clorofórmio ou metil isobutil cetona. A solução para determinação de ferro pode ser obtida por uma re-extração usando soluções de ácido clorídrico 1 mol/L ou ácido nítrico 1 mol/L ou também por uma mineralização da fase orgânica, com uma evaporação do solvente orgânico e digestão do resíduo com ácido nítrico concentrado. O procedimento foi usado para determinação de ferro em amostras de vários sais alcalinos. A técnica da adição padrão foi aplicada e as recuperações obtidas revelaram que o procedimento proposto tem uma boa exatidão.The present paper describes the use of 1-(2-thiazolylazo)-p-cresol (TAC) for separation, preconcentration and determination of iron traces (ng g -1 ) in alkaline salts by the ICP-AES technique. The proposed method is based on the liquid-liquid extraction of the complex formed between iron(III) and 1-(2-thiazolylazo)-p-cresol (TAC). Parameters such as: TAC amount, pH effect, influence of the organic solvent on the extraction, back extraction and mineralization of the organic phase were studied. The results show that the iron(III)-TAC complex, formed in the pH range from 4.0 to 10.0, can be quantitatively extracted from saline solutions (up to 30% NaCl) using isoamyl alcohol, carbon tetrachloride, chloroform or methyl isobutyl ketone as extracting solvent. The solution for the iron determination can be obtained by a back extraction using 1 mol/L hydrochloric acid or 1 mol/L nitric acid solutions or also by mineralization of the organic phase, which was accomplished by evaporation of the organic solvent and digestion of the residue with concentrated nitric acid. The procedure was used for iron determination in several alkaline salt samples. The standard addition technique was applied and the recoveries obtained revealed that the proposed procedure has a good accuracy.

Quick detection of iron in contaminated water before feeding to RO membranes

“…A number of techniques have been used for detection of iron ions in water, viz. atomic absorption spectrophotometer [16,17] and inductively coupled plasma mass spectrometry [18,19]. However, these techniques have limitations, viz.…”

Liquid-Liquid Microextraction with Vortex-Assisted for Determination of Palladium and Gold in Water Samples by Flame Atomic Absorption Spectrometry

“…Therefore, low concentration of analytes and matrix effects are often required a suitable sample pretreatment step. Techniques such as co-precipitation 13 , solid phase extraction [14][15][16] , cloud point extraction 17,18 and liquid-liquid extraction 19,20 are widely used in the separation and preconcentration of trace elements. These preconcentration methods have attributed to improve the sensitive and efficiency in environmental samples.…”

Optimization of the preconcentration system of cadmium with 1(2-thiazolylazo)-p-cresol using a knotted reactor and flame atomic absorption spectrometric detection

“…The 2-(2-thiazolylazo)-p-cresol (TAC) reagent forms insoluble chelates with numerous metal ions. For preconcentration procedures, it was used in liquid liquid extraction for iron determination [29] and for solid phase extraction for cobalt determination [30]. However, it was not used for preconcentration systems, using KR.…”