The Modified Electrode by PEDOP with MWCNTs-Palladium Nanoparticles for the Determination of hydroquinone and Catechol

Abstract

Poly-ethylenedioxypyrrole (PEDOP) coated thiolated multiwall carbon nanotubes palladium nanoparticles (MWCNTs-Pd) modified glassy carbon electrode (GCE) [PEDOP/MWCNTs-Pd/GCE] for the determination of hydroquinone (HQ) and it's isomer catechol (CA) were synthesized and compared with bare GCE and thiolated multiwall carbon nanotubes (MWCNTs-SH/GCE). The modification could be made by simple processes on a GCE with MWCNTs-Pd covered by PEDOP in a 0.05 M tetrabutylammonium perchlorate (TBAP)/MeCN solution system. A well-defined peak potential evaluation of the oxidation of hydroquinone to quinone at 0.05 V (vs. Ag/AgCl), and electrochemical reduction back to hydroquinone were found by cyclic voltammetry (CV) in phosphate buffered saline (PBS) at pH 7.4. Peak current values increased linearly with increasing hydroquinone contents. The peak separation between the anodic and cathodic peaks at the PEDOP/ MWCNTs-Pd/GCE was ΔEp = 40 mV for HQ and ΔEp = 70 mV for CA, resulting in a higher electron transfer rate. Moreover, good reproducibility, excellent storage stability, a wide linear range (0.1 µM -5 mM for HQ and 0.01 µM -6 mM for CA), and low detection limits (2.9 × 10 −8 M for HQ and 2.6 × 10 −8 M for CA; S/N = 3) were determined using differential pulse voltammetry (DPV) and amperometric responses; this makes it a promising candidate as a sensor for determination of HQ and CA.Key Words : Hydroquinone, Catechol, Electrochemical sensor, Carbon nanotubes, MWCNTs-palladium nanoparticles IntroductionSince its introduction for clinical use in 1961, hydroquinone (HQ; 1,4-dihydroxybenzene) has been a popular depigmenting agent, inhibiting melanin formation.1,2 Accordingly, it has been used not only in cosmetic creams and tanning but also pesticides, flavoring agents, medicines, photography chemicals, organic constituent of tobacco smoke, and widely distributed throughout nature.3-6 Nevertheless, HQ and its isomers, catechol (CA; 1,2-dihydroxybenzene) and resorcinol (RE; 1,3-dihydroxybenzene), are harmful to both humans and animals, even at low concentrations, and they are difficult to degrade due to their coexistence and interference during determination.7-10 Moreover, they are considered to be environmental pollutants by the United States Environmental Protection Agency (EPA) and the European Union (EU) and banned its use in cosmetics and such formulations.11 But some researchers have acknowledged that these dihydroxybenzenes not only affect activities of some enzymes, but also have biological importances such as antioxidation and antivirus characterestics, thus are environmentally significant as antioxidants and antiviral agents.12 Therefore, various methods for their determination have been carried out by spectrophotometric and chromatographic techniques.13-15 Unfortunately they possess high cost and low sensitivity, require complicated pretreatments, and consume much time. So, it's demanding to develop simple, rapid, and electrochemical methods with low cost, high sensitivity, and ease of operation. 16,17 From previous re...

Ultrasensitive voltammetric determination of catechol at a gold atomic cluster/poly(3,4-ethylenedioxythiophene) nanocomposite electrode

“…The limit of detection is calculated to be 6.3 pM based on 3 times the standard deviation (s) of the blank value. The reported detection limit was found to be the lowest when compared to the previously reported catechol electrochemical sensors (TableS3of ESI †) [40][41][42][43][44][45][46][47][48][49][50][51][52]. The wider calibration range and low detection limits may be attributed to higher surface area, stability and catalytic effects (in the presence of Cu 2+ ) of the AuAC/PEDOT/Au nanocomposite.…”

“…The reported detection limit was found to be the lowest when compared to the previously reported catechol electrochemical sensors (Table S3 of ESI †). [40][41][42][43][44][45][46][47][48][49][50][51][52] The wider calibration range and low detection limits may be attributed to higher surface area, stability and catalytic effects (in the presence of Cu 2+ ) of the AuAC/PEDOT/Au nanocomposite. The reproducibility of the developed sensor was measured at 10 À9 M and the relative standard deviation (RSD) was found to be 1.23% for three successive measurements using the developed sensor and found to be stable for 1 week when stored dry at room temperature.…”

Enhanced Electrochemical Determination of Catechol and Hydroquinone Based on Pd Nanoparticles/Poly(Taurine) Modified Glassy Carbon Electrode

“…It is necessary to compare the LOD, linearity and other properties of the proposed composite electrode with the other published works (Table ) . The lowest LOD with a good linear range was obtained at Pd/Poly(TAU)/GCE when compared to the reported studies.…”

Electrochemical performance of TiO 2 /Au/carbon nanotubes composite interface for hydroquinone detection

“…However, used to modify electrodes, CNTs typically become entangled, and form kinks that work against electron transfer. However, CNTs loaded with metal particles such as Pd [8], Au [9] and Ag [10] can dramatically improve electronic transmission speeds. De Luca et al [11] reported the hydrogen‐sensing properties of Pt/TiO 2 /MWCNT composites.…”