Novel catalytic fluorescence method for speciative determination of chromium in environmental samples

Sunil Adurty,Jagadeeswara Rao Sabbu

doi:10.1186/s40543-015-0044-7

Abstract

Thiourea derivatives act as promising chemosensors for sensing transition metal ions. 1-(2-hydroxyphenyl)thiourea (HPTU) is one such chromophore that has potential for metal ion sensing. The current investigation reports the sensing of chromium species using transition metal-oxo-based reaction of 1,2-hydroxyphenylthiourea. The catalytic effect of chromium (III) and chromium (VI) on the oxidation of HPTU was studied. The reaction was followed spectrofluorimetrically by measuring the fluorescence intensities of the reaction product at λ ex = 416 and λ em = 520 nm, respectively. Under the optimum analytical conditions, HPTU acts as a chromogenic sensor for the detection of chromium species in nano-gram levels with a determination range of 0.3 to 250 ng/mL. The methods are fairly sensitive, and the role of activators and sensitizers in enhancing the catalysis was studied. Interference due to various cations and anions in the experiment was investigated. The proposed method was applied to environmental samples for the analysis of chromium content.

Highlights

Thiourea derivatives act as promising chemosensors for sensing transition metal ions. 1-(2-hydroxyphenyl) thiourea (HPTU) is one such chromophore that has potential for metal ion sensing
Proposed mechanism The proposed mechanism describes that chromium species complexes with activators like 1,10-phenanthroline, 2,2′-bipyridyl resulting in the formation of organo-metallic complexes
With respect to the observations pertaining to pH study, it was noticed that HPTU reaction was catalysed by chromium(III) ions only in the pH range of 3.5 to 4.2

Summary

Introduction

Thiourea derivatives act as promising chemosensors for sensing transition metal ions. 1-(2-hydroxyphenyl) thiourea (HPTU) is one such chromophore that has potential for metal ion sensing. Thiourea derivatives act as promising chemosensors for sensing transition metal ions. 1-(2-hydroxyphenyl) thiourea (HPTU) is one such chromophore that has potential for metal ion sensing. The current investigation reports the sensing of chromium species using transition metal-oxo-based reaction of 1,2-hydroxyphenylthiourea. The toxicological and biological characteristics of many transition metals like chromium are related to their chemical forms. A great interest in chromium speciation originates from applications of this metal in various industrial activities such as tanning of leather, electroplating, pigment production and wood preservation. Owing to these industrial processes, large amounts of chromium compounds discharge into the environment, which can affect biology and ecology of the environment. Cr(III) appears to be one of the essential elements for the proper functioning of living organisms, effective in the maintenance of normal glucose, cholesterol and fatty acid metabolism, while water soluble Cr(VI) is toxic to human and living organisms and

Methods

Results

Conclusion