**1. Introduction**

Bisphenol A (BPA, 2, 2-bis (4-hydroxy phenyl) propane), is one of the most extensively used industrial compounds in the production of plastics due to its transparent, strong and light characteristics [1]. Till now, BPA has been widely employed as a monomer to synthesize polycarbonate, expoxy resin, polysulfone resin and other various polymer materials [2]. These polymer materials are mostly used to produce storage containers, nursing bottles, thermal papers, medical apparatus, food can linings and supply pipes [3]. However, toxicology studies have

shown that BPA is a typical endocrine-disrupting compound (EDC) in which even a low level can mimic and interfere with hormonal activity by interfering with growth and reproductive development [4, 5]. Consequently, the popular use of BPA has raised serious concerns regarding its implications for food safety and environmental health. In fact, BPA can be released from waste plastics, thermal printing papers, compact disks, powder paints, and adhesives into food and water samples at low concentration (ppb level) and will eventually find its way into the human body [6]. Unsurprisingly, BPA was found to be present in many biological fluids such as human blood, serum, and urine [1]. Although many countries have begun to phase out the use of BPA [7], several of the BPA-containing products that often occupy landfills are still around. This means that BPA will continue to migrate into the environment through runoff and wastewater discharges, eventually contaminating our water resources and food supplies. Therefore, it is still needed to develop a sensitive and simple method for the determination of trace amounts of BPA in the environment. Notably, multiple procedures have been utilized for determining the contents of BPA in diverse matrices, including liquid chromatography-mass spectrometry [8], electrochemiluminescence, colorimetry, liquid chromatography coupled to UV/vis, fluorescence spectrometry, enzyme-linked immunosorbent assay (ELISA) [9], surface-enhanced Raman scattering (SERS) [10] and so forth. These methods can offer good accuracy and sensitivity, however they have some drawbacks, such as high-cost equipment, time consuming operation and unsuitability for onsite analysis [11, 12], thus restricting their application. On contrary, electrochemical sensors have been extensively used as an alternative solution for detecting trace levels of BPA due to their inherent advantages such as low cost, short analysis time, portability and excellent sensitivity [13]. Direct monitor BPA using an electrochemical sensor with a bare electrode has a poor response due to fouling and sluggish electron transfer kinetics [14]. In order to avoid and reduce this problem, several kinds of nanomaterials or their composites with excellent catalytic properties have been employed to modify the electrode. Amongst such materials, porphyrins and their derivatives have been long employed in electrochemical sensors applications [15] thanks to their special electrochemical properties [16]. These latter originated from the highly *π*-conjugated system of porphyrin which is an efficient platform for electron transfer [17]. Indeed, porphyrins are naturally occurring macrocyclic species that bind metals *via* nitrogen donor atoms on four pyrrole subunits, resulting in versatile chelating systems [18]. The coordination sites of porphyrin molecule can easily connected with metal ions such as Fe, Zn, Mg and so on to form stable metallo-porphyrins. This coordination increases the movement capacity of electrons [19], thus the electrocatalytic activity of the porphyrin. Among the metalloporphyrins, iron porphyrins have demonstrated excellent electrocatalysis for many biologically important target molecules [20] thanks to their electronic media role based on their reversible Fe(III)/Fe(II) redox states [21, 22]. Various carbon nanomaterials such as graphene and its derivates have been proven to be excellent carriers to enhance the sensitivity of sensors [23]. Graphene (or reduced graphene oxide, RGO), a 2D material with a single layer of an sp2 carbon atom network densely packed in a honeycomb structure, has unique properties, such as large surface-to-volume ratio, high adsorption capacity, excellent conductivity and easiness of modifications [24]. This innovative nanocarbon material has been inserted into the sensitive membrane to form a nanocomposite as well as into the transducer to form a nanocarbon transducer. Recently, Nanocarbon Transducers based on RGO have enhanced the target analyte current response which makes them attractive for preparing highly sensitive sensors [25]. The aim of this chapter is to study the effect of nanocarbon transducer on the sensitivity of BPA sensor based on iron (III) porphyrin as a sensitive membrane.

*Novel Sensor Based on Nanocarbon Transducer Functionalized by Iron (III) Porphyrin… DOI: http://dx.doi.org/10.5772/intechopen.98560*
