Polarographic Interaction of Nickel (II) with Ammonium Piperidine-1- Carbodithioate: Application to Environmental Samples Suvardhan Kanchi 1* , Bathinapatla Ayyappa 1 , Myalowenkosi I Sabela 1 , Krishna Bisetty 1* and Nuthalapati Venkatasubba Naidu 2 1 Department of Chemistry, Durban University of Technology, Durban, South Africa 2 Department of Chemistry, Sri Venkateswara University, Tirupati, A.P, India * Corresponding authors: Suvardhan Kanchi, Department of Chemistry, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa, Tel: +91-9440722881, +27-373-3004/2311, E-mail: ksuvardhan@gmail.com Krishna Bisetty, Department of Chemistry, Durban University of Technology, P.O. Box 1334, Durban 4000, South Africa Rec date: Jan 21, 2014; Acc date: Mar 10, 2014; Pub date: Mar 12, 2014 Copyright: © 2014 Kanchi S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract This paper describes the interaction of nickel (II) with ammonium piperidine-1-carbodithioate (APC) using Direct Current (DC) polarography (DCP) & differential pulse polarography (DPP) at the Dropping Mercury Electrode (DME) in NH 4 Cl-NH 4 OH buffer medium at pH 6.0. The polarograms shows a predominant peak for nickel (II)-APC at -1.30 V vs SCE, indicating the production of catalytic hydrogen wave (CHW) due to electrostatic interactions between APC and nickel (II). The interactions were characterized with UV-visible spectrophotometer, FT-IR and cyclic voltammetric techniques. The developed method was applied successfully to determine the nickel (II) levels in leafy vegetables and biological samples with acceptable recoveries. Keywords: Direct Current Polarography (DCP); Differential Pulse Polarography (DPP); Nickel (II); Ammonium Piperidine-1- Carbodithiate (APC); Interaction; Environmental samples Introduction Carbodithioates, a group of small organic molecules with a strong chelating ability towards inorganic species that have been extensively been used in the agricultural industry for more than eighty decades. In recent years their applications have not only become apparent as pesticides and fungicides, but also widely used as vulcanization accelerators in the rubber industry [1]. Moreover, carbodithioates are of biological importance due to their antibacterial, antituberclosis and antifungal properties. The insolubility of metal salts (with the exception of sodium and other alkali and alkaline earth metals) and the capacity of the carbodithioates to form stable metal-complexes are mainly responsible for the extensive use of this class of compounds as superior ligands. Furthermore, carbodithioates exhibit strong binding properties with a number of transition metal ions resulting in stable colored complexes [2]. Nickel is ubiquitous in the environment and an essential metal for animal nutrition, and consequently it is probably essential to humans. Nickel is a relatively non-toxic element; however, certain nickel compounds have been proven to be carcinogenic. The main sources of nickel in aquatic systems include dissolution of rocks and soils, biological cycles, atmospheric fallout, and most importantly industrial processes and water disposal [3]. Over toxicity of nickel may cause skin disorder known as Nickel- eczema [4] and other occupational disease [5] especially to workers who handle nickel on regular basis. This skin disorder has also been reported by Cempel and Nikel [6] to appear in people who have great sensitivity to nickel, mostly women, and can be caused by wearing of jewellery made of nickel alloys [6]. While the medical diagnosis is currently established through nickel determination in blood and urine, other studies [7,8] show that disease incidence increased in patients who consume foods rich in nickel, such as oats, nuts, beans and chocolate. Hence, an appropriate knowledge of the nickel content in foods could be of a great interest for the dietary control of nickel- eczema patients. Several analytical techniques such as FAAS [9-13], GFAAS [14-16], ETAAS [17], AFS [18], UV-vis spectrophotometry [19-24] and ICP-OES [25,26] have been proposed for the analysis of nickel (II), but most of these require expensive equipments and time consuming sample preparation procedures. However, the electrochemical analysis of trace amounts of nickel (II) require relatively inexpensive equipment but presents certain difficulties due to their irreversible reduction behavior [27,28] of nickel. Therefore it is needless to say, it has successfully been accomplished using a variety of electro-analytical techniques such as stripping & voltammetric analysis [29-34] including polarography [35]. In this paper, electrochemical and spectrophotometry data are reported on the interaction between nickel(II) and APC, obtained by applying cyclic voltammetry (CV), differential pulse polarography (DPP), FT-IR and UV-visible spectrophotometry. After interaction, the electrochemical behaviour of the complex is studied at DME in presence of NH 4 Cl-NH 4 OH medium at pH 6.0 with the view of attaining catalytic hydrogen wave which ensures the credibility of the method for the determination of nickel (II) in selected leafy vegetables and biological samples. Experimental Chemicals All the experiments were performed at 25°C using freshly prepared solutions. Double distilled mercury and double distilled water were used throughout the experiment. The dissolved oxygen in the solutions was removed by passing a 99.99% pure nitrogen gas through the measuring solution in an electrochemical cell for 10-15 minutes. Standard metal ion solution was prepared taking 0.004050 g L -1 of Environmental Analytical Chemistry Kanchi et al., J Environ Anal Chem 2014, 1:1 http://dx.doi.org/10.4172/ jreac.1000107 Research Article Open Access J Environ Anal Chem ISSN:JREAC an open access journal Volume 1 • Issue 1 • 107