ORIGINAL PAPER Fabrication of an electrochemical sensor based on the electrodeposition of Pt nanoparticles on multiwalled carbon nanotubes film for voltammetric determination of ceftriaxone in the presence of lidocaine, assisted by factorial-based response-surface methodology Saeed Shahrokhian & Niloufar Hosseini-Nassab & Zahra Kamalzadeh Received: 3 May 2013 /Revised: 23 August 2013 /Accepted: 26 August 2013 /Published online: 10 September 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract A glassy carbon electrode (GCE) is modified with platinum nanoparticle (PtNPs) decorated multiwalled carbon nanotube (MWCNT). The modified electrode is applied for the determination of ceftriaxone (CFX) in the presence of lidocaine. Different methods were used to characterize the surface morphology of the modified electrode. The electro- chemical behavior of CFX was investigated at GCE, MWCNT/GCE and PtNPs/MWCNT/GCE. A factorial-based response-surface methodology was used to find out the opti- mum conditions with minimum number of experiments. Under the optimized conditions, oxidation peak currents in- creased linearly with CFX concentration in the range of 0.01– 10.00 μM with a detection limit of 9.01 nM. The results prove that the modified electrode is also suitable for the determina- tion of CFX in pharmaceutical and clinical preparations. Keywords Ceftriaxone . Platinium nanoparticle . Multiwalled carbon nanotube . Experimental design . Cyclic voltammetry Introduction The world of nanomaterials, in general, and metal nanoparticles, in particular, has drawn renewed attention in recent years because of their wide range of applications in sensors, catalysis, biological labeling, photonics, optoelectronics, information storage and many other areas [1–3]. Metal nanoparticles like other nanomaterials show special features that are altered considerably with their structural characteristics [4–6]. Consequently, much effort has been devoted to synthesizing metal nanoparticles with various shapes and sizes [7, 8]. On the other hand, multicomponent assemblies of nanoscale entities have been widely studied due to their collective properties that are drastically different from a simple combination of individual components [9]. Since their discovery, carbon nanotubes (CNTs) have been the subject of intensive research due to possession of extraor- dinary electrical and mechanical properties, good chemical stability and large surface area. These distinctive properties make CNTs as effective supporting materials for immobilizing metal nanoparticles [9–11]. Based on several reports, grafting of metal nanoparticles onto the structure of CNT proposes a novel class of nanocomposite materials with potential appli- cation in wide range of multifunctional systems from sensitive electrochemical sensors to catalyst supports to highly efficient fuel cells. Previously, considerable efforts have been made to prepare CNT–metal nanoparticles assemblies [12–17]. Different be- haviors of metal nanoparticles depending on their size, distri- bution and composition have been investigated. Therefore, it is important to develop effective preparation methods of nanoparticles with well-controlled composition, shape and size [2–4]. Several approaches have been suggested for the deposition of metal NPs on CTs [17, 18]. However, electro- chemical methods are mainly considered for purpose of elec- trodeposition of metallic nanostructures on the surface of the electrode and not for mass preparation in the bulk solution. S. Shahrokhian : N. Hosseini-Nassab : Z. Kamalzadeh Department of Chemistry, Sharif University of Technology, Tehran 11155-9516, Iran S. Shahrokhian (*) Institute for Nanoscience and Technology, Sharif University of Technology, Tehran, Iran e-mail: shahrokhian@sharif.edu J Solid State Electrochem (2014) 18:77–88 DOI 10.1007/s10008-013-2243-8