Direct determination of free metal concentration by implementing stripping chronopotentiometry as the second stage of AGNES

Parat, Corinne; Authier, Laurent; Camaño, David Aguilar; Companys, Encarnació; Puy, Jaume; Galceran, Josep; Potin‐Gautier, Martine

doi:10.1039/c1an15481h

Cited by 37 publications

(47 citation statements)

References 29 publications

(53 reference statements)

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“…Ao fazer sequencialmente AGNES e SSCP a forma mais fácil de quantificar o metal amalgamado em AGNES é usar uma etapa de reoxidação similar à SCP. 60 Na segunda etapa o tempo de reoxidação (τ) é diretamente proporcional a c M,amalg , o qual é diretamente proporcional à concentração de íon metálico no interior da solução segundo:…”

Section: Técnica De Redissolução Nernstiana Na Ausência De Gradientesunclassified

“…108,[112][113][114][115] Sensores impressos de ouro, por exemplo, foram usados para investigar as interações dinâmi-cas de Hg(II) com ácidos húmicos e suspensões de microalgas. 110,111 Assim, estudos recentes têm demosntrado que metais como ouro e bismuto apresentam propriedades eletroquímicas que permitem seu uso em especiação dinâmica, sendo considerados "ambientalmente amigáveis" por serem menos tóxicos e terem enorme potencial para viabilizar a realização de estudos on site.…”

Section: Exemplos De Estudos De Especiação Dinâmica Em Sistemas Modelunclassified

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Especiação Dinâmica De Metais Traço Em Ambiente Aquático Usando Cronopotenciometria De Redissolução Anódica

Monteiro¹,

Goveia²,

Rotureau³

et al. 2018

Quim. Nova

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Recebido em 26/01/2018; aceito em 12/04/2018; publicado na web em 22/05/2018 DYNAMIC SPECIATION OF TRACE METALS IN AQUATIC ENVIRONMENT USING ANODIC STRIPPING CHRONOPOTENTIOMETRY. The contamination of natural environments by trace metals has several adverse effects on human health, which is mainly due to the high toxicity, persistence and reactivity of these species in the environment. To understand the bioavailability of trace metals, it is necessary to know the speciation in equilibrium and the dynamic behavior of the system. In this context, the present work aims to present a bibliographic review about the potentialities of the Stripping Chronopotentiometry (SCP) and Stripping Chronopotentiometry at Scanned Deposition Potential (SSCP) in the study of dynamic trace metal speciation. These techniques have low detection limits and do not suffer interference due to the adsorption of organic matter on the surface of the working electrode. Coupling these techniques with the Absence of Gradients and Nernstian Equilibrium Stripping (AGNES) enables simultaneous determination of free ions, complexation equilibrium constants and diffusion coefficients of the complexes, thus providing information on the dynamic and heterogeneity of the metal complexes in the presence of macromolecules or particles. In this paper we will present the theory of dynamic speciation of trace metals, a detailed description of how to use the techniques to obtain this information, and examples of application in model systems and natural samples.Keywords: metal complexes; metal ions; lability; redissolution techniques; deposition time. INTRODUÇÃOO interesse no estudo de metais traço em solução provém da elevada toxicidade, persistência e reatividade de muitos destes no ambiente. Em ambientes aquáticos naturais, os íons metálicos podem se distribuir em diferentes espécies como resultado das interações com componentes da matriz (matéria orgânica, partículas inorgâni-cas) e das características físico-químicas (temperatura, força iônica, pH, potencial redox, presença de outros íons) do meio. A maioria das espécies formadas tem caráter polifuncional e polieletrolítico, apresentando ampla faixa de constantes de velocidade de formação/ dissociação e de tamanhos, que controlam a biodisponibilidade, toxicidade e mobilidade dos íons metálicos. 1O estudo da distribuição dessas espécies é denominado de especiação de metais. O termo especiação foi definido como a descrição da abundância de um elemento numa amostra (distribuição da espé-cie), enquanto a análise de especiação se refere aos procedimentos analíticos de identificação e/ou medida quantitativa de uma ou mais espécies químicas numa amostra. Cada uma destas espécies pode se comportar de forma diferente em termos de mobilidade e biodisponibilidade em sistemas aquáticos naturais, portanto, estão sujeitas à mudança de condições e praticamente nunca atingem o equilíbrio químico. Isto torna o estudo da especiação muito mais complicado, uma vez que se faz necessária uma compreensão da cinética das reações do ...

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Section: Técnica De Redissolução Nernstiana Na Ausência De Gradientesunclassified

Section: Exemplos De Estudos De Especiação Dinâmica Em Sistemas Modelunclassified

Especiação Dinâmica De Metais Traço Em Ambiente Aquático Usando Cronopotenciometria De Redissolução Anódica

Monteiro¹,

Goveia²,

Rotureau³

et al. 2018

Quim. Nova

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“…Recent developments of AGNES [17][18][19] are making the possibility of on-site measurements realistic, which would avoid numerous problems that can potentially occur during sampling and sample handling of natural solutions (contamination, changes in pH and temperature, loss by adsorption, etc). Obviously, the HMDE is poorly adapted for on-site studies.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, the application of AGNES has been undertaken with thin-film mercury screen-printed electrodes (SPEs), which represent an ideal alternative to the use of the HMDE. [19,20] These sensors have a very small size (9.6 mm 2 ) and use a thin mercury film thickness (200 nm), which make them easy to deploy on site. Unlike the HMDE, SPEs do not need any N 2 pressure and, thus the transport of N 2 bottles to the field, which could be very problematic, is avoided.…”

Section: Introductionmentioning

confidence: 99%

Free Zn2+ determination in natural freshwaters of the Pyrenees: towards on-site measurements with AGNES

Parat¹,

Authier²,

Castetbon³

et al. 2015

Environ. Chem.

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Environmental context. Knowledge of the speciation of metals, especially of the free metal ion concentration, is essential to understand the fate of these elements in rivers and their effects on living organisms. On-site analyses are preferred for these measurements as they allow problems associated with sample transportation and preservation to be avoided. In this context, an on-site methodology based on an electrochemical method and screen-printed sensors has been developed in the laboratory and validated on site.Abstract. An on-site methodology has been developed for the direct determination of free Zn 2þ with AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) in freshwaters. This implementation includes: (i) the use of screenprinted electrodes, which provide good limits of detection and easy transportation and deployment; (ii) no need for sample purging; (iii) a calibration in a synthetic river solution that reproduces the speciation changes of the natural samples well and allows oxygen interference to be minimised; (iv) the addition of a background electrolyte up to 0.01 mol L À1 in both the calibration and freshwater samples; (v) chemical stripping chronopotentiometry as the quantification stage of AGNES. This procedure minimises the effects of working at low ionic strength and in the presence of dissolved oxygen. In the laboratory, the methodology was checked with different natural samples taken from rivers Garonne, Gave de Cauterets and Gave de Pau in the Pyrenees. Results appeared in good agreement with theoretical estimations computed from Visual Minteq. On-site measurements were performed for the first time with AGNES in the Gave de Cauterets in Soulom (France) and the results were corroborated with purged measurements performed in the laboratory.

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“…This is an important parameter as the relative toxicities of different metal species and complexes can be quite notable. Recently TF-SPCEs have been utilised with a technique referred to as absence of gradients and Nernstian equilibrium stripping (ANGES) [31,32]. This is a relatively new technique which has been developed to measure the free ion concentration alone.…”

Section: Introductionmentioning

confidence: 99%

Screen-printed Electrochemical Sensors and Biosensors for Monitoring Metal Pollutants

Honeychurch¹

2012

Insciences J.

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Abstract:The present review (with 231 references) focuses on developments made in the area of screen-printed biosensors and sensors for the determination of metal ions in industrial, environmental and biomedical applications. The year 2012 represents the twentieth anniversary of the first reported application of screen-printed electrodes for the determination of metal ions. Focus is placed on fabrication techniques, operating details and performance characteristics for the selected applications. The greater proportion of articles have utilised the technique of stripping voltammetry, gaining detection limits in the low ng/mL (ppb) region. An increasing percentage of these have explored bismuth as an alternative to mercury for the modification of the carbon electrode surface. However, a steady number of applications have shown the possibility of utilising the unmodified screen-printed carbon, gold or silver electrode surface. More recently the alternative approach of electrochemical biosensors has become a growing area. The majority of these have exploited the inhabitation metal ions exhibit on the enzyme activity of urease, acetylcholinesterase and glucose oxidase gaining detection limits in the sub µg/mL region, however recent applications utilising thiol-functionalised oligonucleotides have been shown the possibility of gaining detection limits as low as 120 ng/L for Hg .

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Direct determination of free metal concentration by implementing stripping chronopotentiometry as the second stage of AGNES

Cited by 37 publications

References 29 publications

Especiação Dinâmica De Metais Traço Em Ambiente Aquático Usando Cronopotenciometria De Redissolução Anódica

Especiação Dinâmica De Metais Traço Em Ambiente Aquático Usando Cronopotenciometria De Redissolução Anódica

Free Zn2+ determination in natural freshwaters of the Pyrenees: towards on-site measurements with AGNES

Screen-printed Electrochemical Sensors and Biosensors for Monitoring Metal Pollutants

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