A lignin polymer nanocomposite based electrochemical sensor for the sensitive detection of chlorogenic acid in coffee samples

Abstract

In this study, an innovative nanocomposite of multiwalled carbon nanotubes (MWCNTs), copper oxide nanoparticles (CuONPs) and lignin (LGN) polymer were successfully synthesized and used to modify the glassy carbon electrode for the determination of chlorogenic acid (CGA). Cyclic voltammetry (CV) emphasised a quasi-reversible, adsorption controlled and pH dependent electrode procedure. In cyclic voltammetry a pair of well distinct redox peaks of CGA were observed at the LGN-MWCNTs-CuONPs-GCE in 0.1 M phosphate buffer solution (PBS), at pH 2. The synthesized nanoparticles and nanocomposites were characterized by Fourier transformation infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and x-ray diffraction (XRD) analyses. Differential pulse voltammetry (DPV) was applied to the anodic peak and used for the quantitative detection of CGA. Under optimal conditions, the proposed sensor showed linear responses from 5 μM to 50 μM, the linear regression equation I pa (μA) = 2.6074 C-5.1027 (R 2 = 0.995), whilst the limit of detection (LOD) and limit of quantifications (LOQ) were found to be 0.0125 μM and 0.2631 μM respectively. The LGN-MWCNTs-CuONPs-GCE were applied to detect the CGA in real coffee samples with the recovery ranging from 97 to 106 %. The developed sensor was successfully applied for the analysis of CGA content in the coffee samples. In addition, electrophilic, nucleophilic reactions and chlorogenic acid docking studies were carried out to better understand the redox mechanisms and were supported by density functional theory calculations.

Nanocomposite Polymeric Materials Based on Eucalyptus Lignoboost® Kraft Lignin for Liquid Sensing Applications

“…High electrocatalytic activity of oxidized lignin films allowed their use in electrode modification for the amperometric detection of ascorbic acid [4], nicotinamide adenine dinucleotide [5], and ozone [11]. Composites of lignin with nanoparticles and carbon nanotubes were used in electrode modification for the amperometric detection of trinitrotoluene [12] and chlorogenic acid [13].…”

Design of a Sensitive and Selective Voltammetric Sensor Based on a Cationic Surfactant-Modified Carbon Paste Electrode for the Determination of Alloxan

“…From the voltammograms ( Figure 10 A) obtained, it is clear that the peak current increases with the increase of the scan rate where both the anodic peak potential and cathodic peak potential shifts toward more positive and negative side, respectively, indicating that the redox action of AL is quasi-reversible. 47 , 48 As shown in Figure 10 B, a linear dependence of the anodic peak current ( I pa ) with the square root of the scan rate ( v 1/2 ) is observed, which recommends that the electrode reaction is a diffusion-controlled process and the linearity equation can be stated as I pa (μA) = −0.4588 + 121.55 v 1/2 (V/s); R 2 = 0.9963. Figure 10 C shows the plot of log I pa versus log v , which shows linearity ( R 2 = 0.9970) with a slope of 0.53, which is in close proximity with theoretical value of 0.5 for the diffusion-controlled process.…”

Electrochemical Detection of Curcumin in Food with a Carbon Nanotube- Carboxymethylcellulose Electrode

“…There are many reports concerning polyphenol analysis with CNT-base electrodes. [13][14][15][16] In contrast, there has been only one report on curcumin sensing with CNT-based electrodes, 9 likely because of the hydrophobic nature of the CNT electrode and the fact that as-synthesised CNT is an agglomeration of molecules. In a previous study, we reported on an electrode with CNT-carboxymethyl cellulose (CMC) dispersion.…”