New Strategies for the Simple and Sensitive Voltammetric Direct Quantification of Se(IV) in Environmental Waters Employing Bismuth Film Modified Glassy Carbon Electrode and Amberlite Resin.

Marzena Adamczyk,Małgorzata Grabarczyk

doi:10.3390/molecules26144130

Marzena Adamczyk, Małgorzata Grabarczyk

Open Access

https://doi.org/10.3390/molecules26144130

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Abstract

An analytical procedure regarding the determination of selenium(IV) by anodic stripping voltammetry exploiting the in situ plated bismuth film electrode is described. Since organics are commonly present in untreated natural water samples, the use of Amberlite XAD-7 resin turns out to be quite important to avoid problems such as the adsorption of these compounds on the working electrode. The optimum circumstances for the detection of selenium in water using differential pulse voltammetry techniques were found to be as follows: 0.1 mol L−1 acetic acid, 1.9 × 10−5 mol L−1 Bi(III), 0.1 g Amberlite XAD-7 resin, and successive potentials of −1.6 V for 5 s and −0.4 V for 60 s, during which the in situ formation of the bismuth film on glassy carbon and the accumulation of selenium took place. The current of the anodic peak varies linearly with the selenium concentration ranging from 3 × 10−9 mol L−1 to 3 × 10−6 mol L−1 (r = 0.9995), with a detection limit of 8 × 10−10 mol L−1. The proposed procedure was used for Se(IV) determination in certified reference materials and natural water samples, and acceptable results and recoveries were obtained.

Highlights

Research has been focused on the speciation of selenium in the natural environment, as the bioavailability and toxicity of this element depend on its concentration in the environment and in a variety of organisms
In response to the above-mentioned demand, in this work, we have described a new sensitive and selective method for the determination of Se(IV) by anodic stripping voltammetry (ASV) using the in situ plated bismuth film electrode as a thin film sensor
The nature and type of electrolytes used have a central role in the voltammetric signal of the sensor toward selenium

Summary

Introduction

Research has been focused on the speciation of selenium in the natural environment, as the bioavailability and toxicity of this element depend on its concentration in the environment and in a variety of organisms. Selenium plays a key role in a variety of biochemical and physiological functions in living organisms, but it will be toxic if it is present excessively. In addition to the range of concentration, the beneficial and toxic effects of selenium are dependent on which chemical form it takes. Inorganic selenium compounds are more toxic than organic ones [2]. Among the selenium inorganic species, selenite Se(IV) and selenate Se(VI) are the most common water soluble species found in aerobic water sources [1]. Selenite is more bioavailable and approximately 10-fold more toxic than selenate [3]. There is a strong need for methods of selenium speciation analysis in order to evaluate its actual risk for the environment in connection with its biological availability and toxicity

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