Simultaneously electrochemical determination of dihydroxybenzen isomers using nano carbon paste electrode modified with Cu (II) complex

Benzenediols or dihydroxybenzenes are organic chemical compounds in which two hydroxyl groups are substituted onto a benzene ring. These aromatic compounds are classed as phenols.There are three isomers of benzenediol: 1,2-benzenediol (the ortho isomer) is commonly known as catechol (CC), 1,3-benzenediol (the meta isomer) is commonly known as resorcinol (RC), and 1,4-benzenediol (the para isomer) is commonly known as hydroquinone (HQ) [1]. There areextremely toxic and some of the harmful effects of these are difficulty with breathing, fever, headache, nausea, swelling, vomiting, worsening of pain, redness and swelling. Therefore, the rapid in situ determination of dihydroxybenzenes pollutants is an important environmentalchallenge because of the easy penetration of such species through membranes or skins of plants, animals and humans. Thus, the simultaneous determination of three isomers for quality control analysis and for medical control is very important [2]. Carbon paste electrodes (CPEs), isinexpensive kind of electrode and possess many advantages such as low background current, wide range of potential application, easy fabrication, rapid surface renewal and compatibility with various types of modifiers, have been widely used as suitable matrixes for preparation ofmodified electrodes [3]. Recently, the modified electrode with Multi-walled carbon nanotube has good electrocatalytic activity, sensitivity, and selectivity; it has also a low detection limitcompared to traditional carbon paste electrodes. Also over recent years, transition metal complexes have been employed for the modification of the electrode surfaces. In this work, a highly sensitive electrochemical sensor for the simultaneous determination of o-, m-, pdihydroxybenzeneisomers was fabricated on modified carbon paste electrode. Under the optimum conditions, the calibration curves for CC, RC and HQ were obtained in the range of 1– 500 μM with the sensitivity of 5.0 μA μM−1 cm−2, 5.62 μA μM−1 cm−2 and 7.45 μA μM−1 cm−2,Tarbiat respectively. The detection limits were found to be 0.3 μmol L−1 for CC, 0.1 μmol L−1 for RC and 0.4 μmol L−1 for HQ based on S/N of 3. The developed method was successfully applied to the simultaneous determination of dihydroxybenzene isomers in synthetic and real samples, and the results are satisfactory.

کلیدواژه ها:

Catechol ، Resorcinol ، Hydroquinone ، Modified electrode ، Voltammetry