Synthesis and application of a functionalized polystyrene resin for on-line preconcentration and determination of cobalt(II) in water samples by flow injection/FAAS

Abstract

Foi desenvolvido um método simples e sensível de espectrometria de absorção atômica em chama com injeção por fluxo para a pré-concentração em linha e determinação de níveis traço de cobalto(II). Uma mini-coluna empacotada com poliestireno clorometilado e funcionalizado com N,N-bis(naftilidenoimina)dietilenotriamina (PS-NAPdien) foi utilizada para o enriquecimento em sistema de fluxo de cobalto(II) a partir de amostras em pH 7.0. Todas as variáveis químicas e de fluxo foram otimizadas. Sob condições ótimas, o gráfico de calibração foi linear na faixa de concentração de 1.0-80.0 e 0.30-0.40 µg L -1 para a pré-concentração de volumes de soluções de 10.0 e 20.0 mL, respectivamente. Os valores de limites de detecção para a pré-concentração de amostras para volumes de 10.0 e 20.0 mL foram 0.75 e 0.25 µg L -1 , respectivamente. Um fator de enriquecimento de 110 para um volume de amostra de 10.0 mL foi obtido. Os desvios padrão relativos para 10 replicatas de cobalto(II) nos níveis de 10.0 e 60.0 µg L -1 foram 4.7 e 3.3%, respectivamente. A exatidão do método proposto foi demonstrada a partir da determinação de Co(II) em diferentes amostras de água usando experimentos de adição e recuperação.A simple and sensitive flow injection-flame atomic absorption spectrometric (FI-FAAS) method was developed for on-line preconcentration and determination of trace levels of cobalt(II). A mini-column packed with a chloromethylated polystyrene, functionalized with N,N-bis(naphthylideneimino)diethylenetriamine (PS-NAPdien) was used for on-line enrichment of cobalt (II) , respectively. An enrichment factor of 110 for a sample volume of 10.0 mL was obtained. The relative standard deviations for 10 replicate determinations of cobalt(II) at the 10.0 and 60.0 µg L -1 levels were 4.7 and 3.3%, respectively. The accuracy of the proposed method was demonstrated by determining Co(II) in different spiked water samples.Keywords: flame atomic absorption spectrometry, on-line preconcentration, flow injection, polystyrene, cobalt(II) IntroductionCobalt is an essential element for humans and animals because it is associated with the synthesis of vitamin B 12 . On the other hand, cobalt is also classified as an environmental toxin. It can harm the natural environment, even at low concentrations, through its inherent toxicity and its tendency to accumulate in the food chain. Therefore, it is clear that the determination of trace amounts of cobalt in biological and environmental samples plays an important role in the fields of environmental surveillance, food control, medicine and toxicology.Atomic spectrometric methods are extensively employed for the quantification of metal species.1 In particular, FAAS has been one of the most applied methods for the determination of inorganic elements in a variety of samples.2 However, its main problem is the low sensitivity for some elements at the µg L -1 level. To improve FAAS sensitivity and selectivity, preconcentration procedures are frequently required. Solid phase extraction (SPE) has found increasing appl...

Sequential eluent injection technique as a new approach for the on-line enrichment and speciation of Cr(III) and Cr(VI) species on a single column with FAAS detection

“…1) was prepared by incorporation of a nitrogen/oxygen donor (N 3 O 2 -type) Schiff base ligand namely NAPdien on the polystyrene (PS) polymeric support. The immobilization reaction of NAPdien on the chloromethylated polystyrene polymer and its characterization details have been reported in our previous papers [34,35]. In these papers, we have also reported the capability of PS-NAPdien in the on-line solid phase preconcentration and determination of Co(II) [34] and Cd(II) [35] in different water samples.…”

“…The immobilization reaction of NAPdien on the chloromethylated polystyrene polymer and its characterization details have been reported in our previous papers [34,35]. In these papers, we have also reported the capability of PS-NAPdien in the on-line solid phase preconcentration and determination of Co(II) [34] and Cd(II) [35] in different water samples. The presence of multi-active chelating sites gives the ability to PS-NApdien to sorb more chromium; Cr(III) is retained by forming a stable complex, and chromate is adsorbed by forming the ion pair molecule [H 2 PS-NApdien] 2+ [CrO 4 ] 2− , where [H 2 PS-NAPdien] 2+ is the protonated form of PS-NApdien in acidic media.…”

“…The immobilization of NAPdien on chloromethylated polystyrene was carried out according to our previously reported procedure [34,35] …”

Synthesis of carbon nanotube‐based nanocomposite and application for wastewater treatment by ultrasonicated adsorption process

“…The XRD pattern of Ag@ZnO/MWCNT-NC shows no shift in the peak positions due to the fact that only a small amount of Ag particles after grain-boundary separation from ZnO crystallites may be going to the substitutional Zn sites as reported in previous works. [46][47][48] The XRD pattern of Ag@ZnO/MWCNT-NC shows an additional diffraction peak at 2θ = 26.2°. This peak is in good agreement with JCPDS card no.…”

Desenvolvimento de procedimentos analíticos limpos empregando multicomutação em sistemas de análises em fluxo para determinação fotométrica de cobalto e cádmio em águas

“…36,40,42,44,45,51,53 Todos estes empecilhos, relacionados a procedimentos manuais, podem ser superados ao empregar sistemas de análise em fluxo. 41,43,51,52,58 Na literatura é visto diferentes metodologias para a determinação de cobalto, empregando espectrofotometria em conjunto com a análise em fluxo e em processos manuais. …”