20 ISSN 1023-1935, Russian Journal of Electrochemistry, 2018, Vol. 54, No. 1, pp. 20–26. © Pleiades Publishing, Ltd., 2018. Published in Russian in Elektrokhimiya, 2018, Vol. 54, No. 1, pp. 24–32. Rapid and Sensitive Determination of Hg(II) Using Polarographic Technique and Application to Chlorophytum comosum 1 Ummihan Taskopran Yilmaz*, Goknur Ozdemir Kum, Saliha Alan Akman, and Hasim Yilmaz Gazi University, Polatlí Science and Art Faculty, Department of Chemistry, Polatlí, Ankara, 06900 Turkey *e-mail: ummihan@hotmail.com Received May 30, 2016; in final form, December 9, 2016 Abstract—A differential pulse polarographic (DPP) method has been used for the indirect determination of Hg(II). With a known amount of cyanuric acid (CA) in polarography cell (B–R buffer, pH 10.5) was added an unknown Hg(II) sample and the Hg(II) concentration is calculated simply from the decrease in the CA peak after reaction with Hg(II). The linear concentration range was between 20 and 120 μM and limit of detection was calculated to be 6.7 μM. The proposed method was successfully applied to the dried leave sam- ples belong to C. comosum plant. The method was extended to the indirect determination of mercury(II) in C. comosum plant and results were in agreement with that obtained by a spectrometric comparison method (ICP-MS). The sufficiently good recoveries and low standard deviations reflect the high accuracy of devel- oped method. Keywords: electrochemical determination, trace, differential pulse polarography, mercury(II), cyanuric acid DOI: 10.1134/S1023193518010032 INTRODUCTION Mercury ions (Hg(II)) are the highly toxic environ- mental pollutants in the aquatic environment. It can pose serious threat to human health and the environ- ment [1, 2]. It has been reported that mercury can accumulate in the human body through food chain, which has severe human health problems, such as brain damage, organ function disablement, and immune system homeostasis disruption [3, 4]. Thus, there is a pressing need to develop highly sensitive methods for the rapid detection of mercury ions’ (Hg(II)) trace concentration in the foodstuff, phar- maceutical or biological samples. Mercury is present in most natural materials at usually very low concentrations and therefore, highly sensitive methods are required for its determination. Spectroscopic, chromatographic, fluorometric meth- ods are used. The methods in already published stud- ies are gas chromatography with flame ionization detection (GC-FID) [5, 6], immunochromatographic strip assay [7], fluorescence detection [8], photolu- minescence dedection [9], atomic absorption spec- trometry (AAS) with flow injection cold vapor [10], mass spectroscopy with inductively coupled plasma (ICP-MS) [11, 12], spectrofluorometry [13], spec- trophotometry [14]. The above-mentioned spectroscopic methods can be used safely in the determination of metals in com- plex matrices; however, they are very expensive when compared with electrochemical techniques and require sophisticated instruments for analysis. The reported methods offer a wide working range and low detection limit, these suffer from one or more draw- backs such as tedious sample preparation, extraction process and long analysis time. To overcome these limitations, over the past few years, many types of sensors for Hg(II) ion detection based on oligonucleotides [15], DNA or DNA zymes [16, 17], conjugated polymers [18], proteins [19] and gold nanoparticles [20, 21] have been improved. In this respect, the development of different colo- rimetric or fluorescence-based optical sensors for determination of mercury plays a significant role [22, 23]. Most of the reported colorimetric sensors are based on using organic molecules that normally play in organic media and, consequently, do not take on the selectivity and sensitivity requirements for the detection of mercury in aqueous solutions. This sensor is based on the Hg(II)-induced confor- mational change of a single-stranded DNA (ssDNA) which involves an electroactive, ferrocene—labeled DNA hairpin structure and provides strategically the selective binding of a thymine-thymine mismatch for the Hg(II) ion. The developed sensor showed a linear 1 The article is published in the original.