Surface Plasmon Resonance Sensing Detection of Mercury and Lead Ions Based on Conducting Polymer Composite

Abstract

A new sensing area for a sensor based on surface plasmon resonance (SPR) was fabricated to detect trace amounts of mercury and lead ions. The gold surface used for SPR measurements were modified with polypyrrole-chitosan (PPy-CHI) conducting polymer composite. The polymer layer was deposited on the gold surface by electrodeposition. This optical sensor was used for monitoring toxic metal ions with and without sensitivity enhancement by chitosan in water samples. The higher amounts of resonance angle unit (ΔRU) were obtained for PPy-CHI film due to a specific binding of chitosan with Pb2+ and Hg2+ ions. The Pb2+ ion bind to the polymer films most strongly, and the sensor was more sensitive to Pb2+ compared to Hg2+. The concentrations of ions in the parts per million range produced the changes in the SPR angle minimum in the region of 0.03 to 0.07. Data analysis was done by Matlab software using Fresnel formula for multilayer system.

Polymerization of PEDOT/PSS/Chitosan-Coated Electrodes for Electrochemical Bio-Sensing

“…In this study, the immersion of the PEDOT/PSS/chitosan-coated electrodes into Dex solution, the electrochemical properties of the PEDOT/PSS/chitosan-coated electrodes were altered with time at first, then stay at a constant level. Chitosan facilitating the immobilization of molecular or ions [19,30] could result in the permeability of Dex into the PEDOT/PSS/chitosan coatings increasing with time at first. The electrochemical properties of the PEDOT/PSS/chitosan-coated electrodes reached constant levels, probably due to the saturation of the binding sites available on the PEDOT/PSS/chitosan coatings.…”

“…As a matter of fact, previous studies have revealed that several conducting polymers/chitosan coatings or films can be used for electrochemical bio-sensing. For example, polypyrrole/chitosan conducting polymer composite was used for toxic metal Pb 2+ and Hg 2+ ion detection [19]. Polyaniline/chitosan hybrid conducting polymers were used for detection of Ochratoxin-A, one of a mycotoxin [30], and a breast cancer susceptible gene [21].…”

“…Chitosan can favor the immobilization of biomolecules over its surface. It has been reported that chitosan has an excellent property of immobilization and protection of the bio-sensing elements, such as for DNA probes [17,18] and tonic metal ions [19] and, thus, can be used for monitoring cancer-susceptible genes and metal ions. Even though chitosan is a non-conductive biomaterial it can, however, be modified or doped into conducting polymers, such as polyaniline [20,21] and polypyrrole [19,22], and these conducting polymer/chitosan coatings can be used for electrochemical sensing detections.…”

“…Electrochemical techniques, such as traditional cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), have been widely used for bio-sensing purposes [25][26][27]. Although electrochemical biosensor systems based on polyaniline/chitosan [20,21] and polypyrrole/chitosan [19,22] have been investigated, however, polymers of PEDOT/chitosan for bio-sensing has not been reported. In this study, EDOT, poly(styrene sulfonate) (PSS) (acting as count ions), and chitosan were subjected to electrochemical reactions and the PEDOT/PSS/chitosan coatings were electrodeposited on the surface of platinum (Pt) electrodes.…”

Reduced Graphene Oxide Decorated with Polypyrrole Nanoparticles Layer for Detection of Pyrene Using Surface Plasmon Resonance Technique

“…18 In order to enhance the sensitivity, selectivity, and accuracy of the SPR sensor, carefully chosen polymers films are used to modify the gold or silver layer. Hence, polypyrrole, 19 polypyrrolechitosan, 20 and polypyrrole/multi-walled carbon nanotubes 17 are used to improve the pertinent parameters of the SPR sensor.Conducting polymers such as polypyrrole, polypyrrole-chitosan, polyanilin, and polythiophene 21 have particularly optical and magnetic properties, thermal stability, high conductivity. 22 They have π-electron conjugation 23,24 which is responsible for electronic properties, low energy optical transition and high electron affinity.…”