Complex Formation in a Liquid-Liquid Extraction System Containing Vanadium(IV/V), 2,3-Dihydroxynaphtahlene and Thiazolyl Blue.

Vassil B. Delchev,Galya K. Toncheva,Zlatimir T. Zhelev,Kiril B. Gavazov

doi:10.17344/acsi.2018.4225

Abstract

Liquid-liquid extraction systems for VIV/V containing 2,3-dihydroxynaphtahlene (DN) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (thiazolyl blue, MTT) were studied. The optimum conditions for VIV and VV extraction were found. VIV is extracted in chloroform as a 1:2:2 complex (V:DN:MTT) with lmax = 570 nm and e570 = 2.9´104 dm3 mol-1 cm-1. However, this wavelength was found unsuitable for precise spectrophotometric measurements due to time dependent absorbance changes. VV forms predominantly a 1:1:1 complex with lmax = 335 nm. The calibration graph for this oxidation state is linear in the range of 0.06-1.5 mg cm-3. The molar absorptivity, Sandell's sensitivity and limit of detection were calculated to be 1.6 ´ 104 dm3 mol-1 cm-1, 3.2 ng cm-2 and 0.02 mg cm-3, respectively. The ground-state equilibrium geometries of the anionic parts of the extracted ion-associates, [VIVO(DN2-)2]2-and [VVO2(DN2-)]-, were optimized at the BLYP/6-31++G* level of theory.

Highlights

Vanadium is an essential trace element for living organisms[1] and a pillar of modern technology[2] with a potentially significant environmental impact due to human activity, such as the burning of fossil fuels, manufacturing of steel alloys, dyes, glass and ceramics, and application as a catalyst in various processes.[2,3] Vanadium is the fifth most abundant transition element in the Earth’s crust with an average content of 0.014%.3 Natural sources of airborne vanadium include continental dust, volcanic activity, marine aerosols and wild forest fires.[2]It is known that prolong exposure to vanadium increases the risk of lung cancer and can damage the integumentary, respiratory, central nervous and digestive systems.[4]
The amount of vanadium resorbed in the gastrointestinal tract is a function of the oxidation state and coordination environment.[5]
The following variables were considered for the performed liquid-liquid extraction (LLE)-spectrophotometric optimisation experiments: organic solvent, wavelength for spectrophotometric measurements, pH, extraction time and concentration of the reagents

Summary

Introduction

Vanadium is an essential trace element for living organisms[1] and a pillar of modern technology[2] with a potentially significant environmental impact due to human activity, such as the burning of fossil fuels, manufacturing of steel alloys, dyes, glass and ceramics, and application as a catalyst in various processes.[2,3] Vanadium is the fifth most abundant transition element in the Earth’s crust with an average content of 0.014%.3 Natural sources of airborne vanadium include continental dust, volcanic activity, marine aerosols and wild forest fires.[2]It is known that prolong exposure to vanadium increases the risk of lung cancer and can damage the integumentary, respiratory, central nervous and digestive systems.[4]. Vanadium is an essential trace element for living organisms[1] and a pillar of modern technology[2] with a potentially significant environmental impact due to human activity, such as the burning of fossil fuels, manufacturing of steel alloys, dyes, glass and ceramics, and application as a catalyst in various processes.[2,3] Vanadium is the fifth most abundant transition element in the Earth’s crust with an average content of 0.014%.3. Natural sources of airborne vanadium include continental dust, volcanic activity, marine aerosols and wild forest fires.[2]. It is known that prolong exposure to vanadium increases the risk of lung cancer and can damage the integumentary, respiratory, central nervous and digestive systems.[4] The amount of vanadium resorbed in the gastrointestinal tract is a function of the oxidation state and coordination environment.[5] The most important oxidation states of vanadium are IV and V. The ability to switch between them, along with the stereochemical flexibility of this element[6] are key factors that determine its role in biological systems.[1,7]

Methods

Results

Conclusion