REV. CHIM. (Bucharest) ♦ 65 ♦ No. 1 ♦ 2014 http://www.revistadechimie.ro 39 Improved Stability and Catalytic Activity of Screen Printed Electrode Modified with PB in the Presence of Anionic Surfactant FLORENTINA HUTANU 1 , MIHAELA BADEA DONI 2 , CORNEL MUNTEANU 3 , SIMONA PETRESCU 3 , MARIA MARCU 3* 1 Stefan cel Mare University of Suceava, 13 Universitatii Str., 720229, Suceava, Romania 2 INCDCP- ICECHIM, 202 Splaiul Independentei, 060021, Bucharest, Romania 3 Romanian Academy, Institute of Physical Chemistry Ilie Murgulescu, 202 Spl. Independentei, 060021, Bucharest, Romania In this article is reported the effect of anionic surfactants AOT (dioctyl sulfosuccinate) in the electrodeposition of Prussian Blue (PB) onto screen-printed carbon electrodes (SPCE). The SPCE/PB/AOT electrode displayed a significant improvement of its electrochemical properties and of its stability compared with PB modified SPCE formed in absence of surfactant. The effects of AOT concentration and applied potential on the sensor response to H 2 O 2 are discussed. The PB film stabilized with AOT, were characterized by Scanning electron microscopy (SEM), and Raman spectroscopy. The new electrodeposed PB/AOT film proved excellent electroanalytic properties for H 2 O 2 determination and is a promising material for assembling biosensors based on oxidoreductase enzymes. Keywords: Prussian blue, electrochemical, AOT, hydrogen peroxide, screen printed carbon electrode * email: m_marcu2000@yahoo.com; Tel:0213167912 / 16 Prussian blue is a material which has been extensively investigated due to its electrochemical, photophysical, and magnetic properties and potential analytical applications [1-3]. In 1978, Neff [4] reported for the first time the successful deposition of Prussian blue on a platinum foil as well as its electrochemical behaviour [5-7]. From thereon, enormous number of studies has used different methods for preparation of PB-modified electrodes which have been reported in the literature [8]. The PB modified electrodes developed by Karyakin et al. [9] is based on the reduction of H 2 O 2 rather than on its oxidation. Using iron hexacyanoferrate (Prussian Blue - PB) as an electro- catalyst, H 2 O 2 can be detected at potentials below 0 mV (vs. SCE) with high sensitivity and specificity thus eliminating problems with interfering compounds [9-11]. Itaya and co-workers reported an electrochemical method of PB films preparation, which is based on the electrochemical reduction of a solution of ferric ferricyanide under galvanostatic conditions on platinum, glassy carbon and SnO 2 electrodes [12-13]. The surfactants have been employed in a great number of applications in chemistry [14], exploiting their tendency to accumulate at a surface or interface between two different phases, such as the electrode-solution. This property has been utilized in recent years in the surface modification of electrodes with PB and other hexacyananoferrates, where the presence of added surfactant offers enhanced film, improved stability and excellent electrochemical reversibility [15-18]. Although, studies to date have focused mainly on the use of cetyltrimethyl ammonium bromide (CTAB), we have recently shown the other cationic surfactants such as benzethonium chloride (BZTC) may also be used successfully [19]. The aim of this article was to optimize the electro- deposition of PB in presence of AOT and to study the electrochemical and analytical properties of different modified AOT/PB films. The improved electro-deposition methods, permeability of the optimized AOT/PB provide a further boost in its sensitivity for H 2 O 2 detection, which can be a critical parameter in biosensor design and application. Experimental part Equipment, materials and methods Apparatus Electrochemical measurements were carried out using a Autolab potentiostat/galvanostat computer controlled by the GPES software and a PARSTAT 4000 potentiostat/ galvanostat controlled via VersaStudio software with FRA module. The morphology of the samples were investigated by scanning electron microscopy (SEM) using a high- resolution microscope, FEI Quanta 3D FEG model, at an accelerating voltage of 5 kV, in high vacuum mode with Everhart-Thornley secondary electron (SE) detector. Unpolarized solid state Raman spectra were recorded by means of a LabRam HR spectrometer (Jobin-Yvon- Horiba) over 50-2400 cm -1 range. The 514 nm line of an Ar + laser was used as exciting radiation with the power within 4-6 mW. The backscattered light was collected through the x 50 objective of an Olympus microscope at a confocal hole of 200 μm. The diameter of the laser spot on the sample surface amounted to 2-3 mm providing a spectral resolution better than 2 cm -1 . Electrodes Screen-printed carbon electrodes (SPCE) model DRP- 110 purchased from DropSens (Spain) were used for electrochemical measurements. In this case the electro- chemical cell is composed by a graphite working electrode (d = 4 mm), a graphite auxiliary electrode and a silver pseudo-reference electrode, with silver electric contacts deposed on a ceramic substrate. Reagents All chemicals from commercial sources were of analytical grade. Iron chloride (FeCl 3 ), potassium ferricyanide K 3 [Fe(CN) 6 ], HCl 37%, sodium chloride, hydrogen peroxide (30%) and Dioctyl sulfosuccinate sodium salt (AOT), Sodium dihydrogen phosphate Na 2 HPO 4 · 2H 2 O 2 , disodium hydrogen phosphate KH 2 PO 4 , KCl were purchased from Sigma-Aldrich.