An anionic resin modified by di-2-pyridyl ketone salicyloylhydrazone as a new solid preconcentration phase for copper determination in ethanol fuel samples

Abstract

A adsorção do DPKSH em resina aniônica foi investigada a 25 ± 1 °C e em pH 12 com base em três modelos cinéticos pseudo-primeira ordem, pseudo-segunda ordem e difusão intra-partícula. Os dados experimentais foram aplicados com sucesso aos modelos das isotermas de Langmuir, Freundlich e Dubinin-Radushkevich (D-R). A resina aniônica modificada com DPKSH foi usada na determinação espectrofotométrica do cobre após pré-concentração em linha. Nas melhores condições, foi observada uma resposta linear entre 20 e 80 mg L , respectivamente, com um nível de confiança de 95%, e um fator de pré-concentração igual a 11. O desvio padrão relativo foi estimado em 2,6% para a concentração de 32 mg L -1 Cu(II) (n = 20). Os resultados obtidos na determinação de cobre em amostras de etanol combustível apresentaram concordância, com um nível de confiança de 99%, aos obtidos por espectrometria de absorção atômica com chama (F AAS).The adsorption of DPKSH onto anionic resin was investigated at 25 ± 1 °C and pH 12 on the basis of three kinetic models including pseudo-first order, pseudo-second order and intraparticle diffusion. Isotherm equations including Langmuir, Freundlich and Dubinin-Radushkevich (D-R) were successfully applied to model the experimental data. An anionic resin loaded with DPKSH was used in a flow system for the in-line concentration of copper prior to spectrophotometric determination. Under optimized conditions, a linear response was observed between 20 and 80 µg L , respectively, at the 95% confidence level with an enrichment factor of 11. The relative standard deviation was estimated to be 2.6% for 32 mg L -1 Cu(II) (n = 20). The results obtained for copper determination in ethanol fuel samples agreed with those achieved by flame atomic absorption spectrometry (F AAS) at the 99% confidence level.

Atomic spectrometry update. Industrial analysis: metals, chemicals and advanced materials

“…73 Good agreement with results generated using AAS was observed, and low mg L À1 detection was achieved. An interesting paper was presented by Garcia and colleagues who modified an anionic resin with di-2-pyridyl ketone salicyloylhydrazone to use it as a solid preconcentration phase for Cu determination in ethanol fuel samples, prior to spectrophotometric determination.…”

An environmentally friendly analytical procedure for nickel determination by atomic and molecular spectrometry after cloud point extraction in different samples

“…These results were in agreement with those observed in complexation of other metals with DPKSH. [30][31][32][33] So, a 0.10 mol L À1 acetate buffer solution of pH 4.6 was used for further experiments.…”

“…Zn(II), Fe(II), Fe(III) and Cu(II). [30][31][32][33]37 The effect of acidity on Ni(II) complexation with DPKSH and thus the formation of hydrophobic species was investigated from pH 2.5 to 9.5 using appropriate buffer solutions (CH 2 ClCOONa-CH 2 ClCOOH at pH 2.5 or 3.0, CH 3 COONa-CH 3 COOH at pH 4.0, 4.6 and 5.5; CH 3 COONH 4 at pH 7.0 and Tris/HTris + at pH 8.0 or 9.5). The analytical signal increased with pH up to 5.5, as shown in Fig.…”

“…19,28,29 Di-2-pyridyl ketone salicyloylhydrazone (DPKSH) is a complexing agent which has been used in the spectrophotometric determination of metal ions, including Fe(II) and Fe(III) in natural waters, 30 Zn in pharmaceutical and biological materials 31,32 and Cu in ethanol fuel. 33 Moreover, DPKSH has been immobilized onto silica gel, 34 XAD 2, XAD 7 35 and IRA 402 resins 33 aimed at solid phase extraction and preconcentration of metallic ions.…”

Analytical approaches for the determination of cobalt, nickel and copper by aeration-assisted homogeneous liquid–liquid microextraction and flame atomic absorption spectrometry

“…[21] This technique suffers from some drawbacks such as chemical interference from the sample matrix and high detection limit. In order to overcome these problems, various preconcentration/separation methods including cloud point extraction (CPE), [22] solid-phase extraction (SPE), [23][24][25][26] solid phase microextraction (SPME) [27][28][29][30] and dispersive liquid-liquid microextraction (DLLME) [30][31][32][33][34] were used.…”