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

Journal of Analytical Science and Technology, Feb 2015

Background 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. Methods 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. Results 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. Conclusions 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.

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

Adurty and Sabbu Journal of Analytical Science and Technology Novel catalytic fluorescence method for speciative determination of chromium in environmental samples Sunil Adurty 0 Jagadeeswara Rao Sabbu 0 0 Department of Chemistry, Sri Sathya Sai Institute of Higher Learning (Deemed to be university) , Prasanthi Nilayam-515134, Puttaparthi, Anantapur District, Andhra Pradesh , India Background: 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. Methods: 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 ex = 416 and em = 520 nm, respectively. Results: 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. Conclusions: 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. 1-(2-hydroxyphenyl) thiourea; Chromium; Speciative determination; Catalytic fluorescence - Background 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. Therefore, speciation analysis of chromium is of great importance to assess pollution levels. Chromium mainly exist in two oxidation states, i.e. Cr(III) and Cr(VI). 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 was found to be carcinogenic. Due to the different toxicities of Cr(III) and Cr(VI), and due to their association in many sample matrices, it is necessary to develop methods where both species can be determined simultaneously (Kotas and Stasicka 2000). In the past years, various analytical techniques such as atomic absorption spectrometry (AAS) (Karosi et al. 2006; Ren et al. 2007) spectrophotometry (Wu et al. 2007), stripping voltammetry (SV) (Grabarczyk et al. 2006), inductively coupled plasma-mass spectrometry (ICP-MS) (Sun et al. 2006), inductively coupled plasma-optical emission spectrometry (ICPOES) (Schramel et al. 1992), and high performance liquid chromatography (HPLC) (Padarauskas and Naujalis 1998) have been successfully used to determine chromium in various samples. An extensive coverage of the available methods for chromium determination was put forth by Gomez and Callao, including the various types of sample matrices selected for the determination (Gomez and Callao 2006). Reagents such as bis-[2-hydroxy-1-naphthaldehyde] thiourea (Kiran et al. 2008), quercetin (Hosseini and Belador, 2009), chromotropic acid (CA) (Themelis et al. 2006), bis (salicylaldehyde) orthophenylenediamine (BSOPD) (Arancibia et al. 2012 and Soomro et al. 2011), etc. have been used. Methods such as solidified floating organic drop microextraction (SFODME) in combination with graphite furnace atomic absorption spectrometry (GFAAS) (Moghadam et al. 2011), cloud point extraction (CPE) using diethyldithiocarbamate (DDTC) as the chelating agent (Yildiz et al. 2011), solid phase extraction procedure using ICP-MS (Guerrero et al. 2012), fluorescence method using tetraphenylphosphonium bromide (TPP+Br) (El-Shahawi et al. 2011), EPA methods 3060A and 3052 (Martone et al. 2013), a disposable dual screen-printed electrode method using batch and flow analysis (SnchezMoreno et al. 2010), p-aminoacetophenone and phloroglucinol (Parmar et al. 2010), ultrasoundassisted cloud point extraction (UACPE) (Hashemi and Daryanavard 2012), electrospray ionization mass spectrometry using CYDTA (Hotta et al. 2012), HPLC and preconcentration by CPE with 1-(2-thiazolylazo)-2-naphthol (TAN) as the chelating agent (Wang et al. 2010), ytterbium (III) hydroxide (Duran et al. 2009), mixed-micelle cloud point extraction using electrothermal atomic absorption spectrometry (ET-AAS) (Ezoddin et al. 2010), room temperature ionic liquids (RTILs) for hollow fiber liquid phase microextraction (HF-LPME) com (...truncated)


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Sunil Adurty, Jagadeeswara Rao Sabbu. Novel catalytic fluorescence method for speciative determination of chromium in environmental samples, Journal of Analytical Science and Technology, 2015, pp. 7, Volume 6, Issue 1, DOI: 10.1186/s40543-015-0044-7