Detection of nitrite using poly(3,4-ethylenedioxythiophene) modified SPCEs

Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
Sensors and Actuators B Chemical (Impact Factor: 4.1). 06/2009; 140(1):51-57. DOI: 10.1016/j.snb.2009.04.047


The poly(3,4-ethylenedioxythiophene) (PEDOT)- and PEDOT/multi-wall carbon nanotubes- (PEDOT/MWCNTs) modified screen-printed carbon electrodes (SPCEs) were fabricated and their catalytic properties towards nitrite were studied. Due to the electrostatic interaction between the negatively-charged nitrite ions and the positively-charged PEDOT film, the operating potential for nitrite oxidation was shifted about 160 mV to negative side, compared to bare SPCE, as a PEDOT film was deposited on the SPCE. The diffusion coefficient obtained from RDE experiment is 2.05×10−5 cm2 s−1. The electron transfer coefficient (α) was increased from 0.515 to 0.615 as the sensing electrode was changed from PEDOT-modified to PEDOT/MWCNTs-modified electrode. Therefore, PEDOT/MWCNTs composite shows the superior catalytic property towards nitrite and the operating potential was further shifted about 100 mV to the negative side. The sensitivity and limit of detection (LOD) for the PEDOT- and PEDOT/MWCNTs-modified SPCEs are about 100 mA cm−2 M−1, 1.72 μM and 140 mA cm−2 M−1, 0.96 μM, respectively. The possible interferences from several common ions were tested. The developed sensor was also applied to the determination of nitrite concentration in tap water sample.

  • Source
    • "Poly(3,4-ethylenedioxythiophene) (PEDOT) has become one of the most intensively studied conducting polymers due to its excellent conductivity, chemical stability, and electrocatalytic properties. In addition to its potential application for the detection of important analytes, such as dopamine [20], nitrite [21], and ascorbic acid [22], the pristine PEDOT and its composite with Pt have also been explored in the fields of fuel cells [23-25], photovoltaics [26-28], and super-capacitors [29,30]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Poly(3,4-ethylenedioxythiophene)-Pt nanoparticle composite was synthesized in one-pot fashion using a photo-assisted chemical method, and its electrocatalytic properties toward hydrogen peroxide (H2O2) was investigated. Under UV irradiation, the rates of the oxidative polymerization of EDOT monomer along with the reduction of Pt4+ ions were accelerated. In addition, the morphology of PtNPs was also greatly influenced by the UV irradiation; the size of PtNPs was reduced under UV irradiation, which can be attributed to the faster nucleation rate. The immobilized PtNPs showed excellent electrocatalytic activities towards the electroreduction of hydrogen peroxide. The resultant amperometric sensor showed enhanced sensitivity for the detection of H2O2 as compared to that without PtNPs, i.e., only with a layer of PEDOT. Amperometric determination of H2O2 at -0.55 V gave a limit of detection of 1.6 μM (S / N = 3) and a sensitivity of 19.29 mA cm-2 M-1 up to 6 mM, with a response time (steady state, t95) of 30 to 40 s. Energy dispersive X-ray analysis, transmission electron microscopic image, cyclic voltammetry (CV), and scanning electron microscopic images were utilized to characterize the modified electrode. Sensing properties of the modified electrode were studied both by CV and amperometric analysis.
    Full-text · Article · Jun 2012 · Nanoscale Research Letters
  • Source
    • "Electrochemical analysis was conducted by integrating the proposed system with a nitrite amperometric sensor [30] and a pH potentiometric sensor [31] in vitro. The nitrite sensor was immersed into a 0.1 M phosphate-buffered-saline (PBS) solution (pH 6). "
    [Show abstract] [Hide abstract]
    ABSTRACT: A real-time telemetry system, which consists of readout circuits, an analog-to-digital converter (ADC), a microcontroller unit (MCU), a graphical user interface (GUI), and a radio frequency (RF) transceiver, is proposed for amperometric and potentiometric electrochemical sensors. By integrating the proposed system with the electrochemical sensors, analyte detection can be conveniently performed. The data is displayed in real-time on a GUI and optionally uploaded to a database via the Internet, allowing it to be accessed remotely. An MCU was implemented using a field programmable gate array (FPGA) to filter noise, transmit data, and provide control over peripheral devices to reduce power consumption, which in sleep mode is 70 mW lower than in operating mode. The readout circuits, which were implemented in the TSMC 0.18-μm CMOS process, include a potentiostat and an instrumentation amplifier (IA). The measurement results show that the proposed potentiostat has a detectable current range of 1 nA to 100 μA, and linearity with an R2 value of 0.99998 in each measured current range. The proposed IA has a common-mode rejection ratio (CMRR) greater than 90 dB. The proposed system was integrated with a potentiometric pH sensor and an amperometric nitrite sensor for in vitro experiments. The proposed system has high linearity (an R2 value greater than 0.99 was obtained in each experiment), a small size of 5.6 cm × 8.7 cm, high portability, and high integration.
    Full-text · Article · Dec 2011 · Sensors
  • Source
    • "Chemical sensors play an important role in environmental monitoring , healthcare, industrial production, national security, with economic impact on medicine, agriculture, aerospace industries and so on [1] [2] [3] [4] [5]. In recent years, many kinds of sensing materials like metal oxides [6] [7], polymers [8] [9], and polyelectrolytes [10] have been used to serve these applications. Among these materials, zinc oxide (ZnO), as an n-type semiconducting metal oxide, due to its chemical sensitivity to volatile and radical gases, high chemical stability, easy doping, non-toxicity, and low cost has witnessed an explosion of interest as an excellent candidate material for gas sensing [11] [12] [13]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Mesoporous ZnO–SiO2 composites with various Si/Zn molar ratios were synthesized through a simple one-pot sol–gel method and their humidity sensing properties were also examined. Compared with pure SBA-15, ZnO–SiO2 composite shows improved humidity sensing properties and the introducing level of ZnO has a great influence on the humid sensitivity of ZnO–SiO2 composites. The results exhibited that the sample with Si/Zn = 1 showed better humidity sensing properties than others within the range of 11–95% relative humidity (RH). Its impedance changed by more than four orders of magnitude over the whole humidity range. The response and recovery time were about 50 s and 100 s, respectively. High sensitivity and low hysteresis were also observed. A possible mechanism was suggested to explain the humidity sensitive properties.
    Full-text · Article · Aug 2010 · Sensors and Actuators B Chemical
Show more