Impedimetric Sensor for Pentoses Based on Electrodeposited Carbon Nanotubes and Molecularly Imprinted poly-o-phenylenediamine

Abstract

Impedimetric D-Xylose and D-Arabinose sensors was development from composite electrodes of graphite and histological paraffin, modified with functionalized multi-walled carbon nanotubes (FMWCNTs) based on molecular imprinted poly-ophenylenediamine (poly-o-PD). The contribution of this work was not only the development of a D-xylose and D-Arabinose MIP impedimetric sensor with good performance, but also the electrodeposition method for FMWCNTs onto surface of graphite composites electrodes with ease of control and reproducibility of the electrodeposition process. The sensors were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), field emission gun scanning electron microscopy (FEG-SEM) and RAMAN spectroscopy. The MIPs sensors for the pentoses have good selectivity, sensitivity in the concentration range of 1.0 × 10 −11 to 1.0 × 10 −10 mol l −1 with limit of detection (LOD) of 4.50 × 10 −12 mol l −1 for D-Xylose and 4.25 × 10 −12 mol l −1 for D-Arabinose. MIPs was applied to determination of pentoses in samples of sugarcane bagasse hydrolysates using the standard addition method and validated by recovery study, which presented satisfactory results between 92.9% and 115.5%.

NiOOH/FeOOH Supported on Reduced Graphene Oxide Composite Electrodes for Ethanol Electrooxidation

“…The electrodes were made using a syringe and a copper wire was connected. After the electrodes (EGP) were confected, a composite graphite-paraffin mixture was prepared [9]. The mixture of graphite and paraffin was carried out with constant heating of 80 °C and the resulting slurry homogenized was inserted into syringe and cured at room temperature for 1 day.…”

Characterization of Electrochemical Sensors Based on Carbon Nanotubes and MIPS for Determination of Ferulic Acid

“…The substrates were prepared from a graphite/paraffin mixture in the proportion of 7:3 (v/v), similar to that described in the literature [6,7]. The modification of the electrode surface is carried out by electrodeposition of FMWCNTs in the range of −0.5 to 1.0 V for 15 consecutive cycles at a scanning speed of 50 mVs −1 [8][9][10]. This can also be achieved by electropolymerization of MIPs in a range of −0.4 to 1.0 V for 20 cycles, with a speed of 50 mV −1 in a standard acetate solution with pH 5.0 containing 5.0 × 10 −3 mol L −1 o-PD and 9.0 × 10 −4 mol L −1 of ferulic acid, similarly to the literature [8,11].…”

“…The modification of the electrode surface is carried out by electrodeposition of FMWCNTs in the range of −0.5 to 1.0 V for 15 consecutive cycles at a scanning speed of 50 mVs −1 [8][9][10]. This can also be achieved by electropolymerization of MIPs in a range of −0.4 to 1.0 V for 20 cycles, with a speed of 50 mV −1 in a standard acetate solution with pH 5.0 containing 5.0 × 10 −3 mol L −1 o-PD and 9.0 × 10 −4 mol L −1 of ferulic acid, similarly to the literature [8,11]. For the extraction step the dimethylformamide/acetic acid solution (5:2, v/v) is used, where the modified electrodes are immersed for 60 s. Afterwards, the adsorption process is performed, where the sensor is immersed in a standard acetate solution with pH 5.0 containing 9.0 × 10 −4 mol L −1 of ferulic acid for 7 min, in order to fill the cavities left after the extraction step.…”

Optical Properties of Composites Based on Poly(o-phenylenediamine), Poly(vinylenefluoride) and Double-Wall Carbon Nanotubes

“…The composites based on POPD and various carbon nanoparticles were intensely studied for a wide range of applications. In order to support this sentence, we note that in the case of: (i) the POPD/graphene composites, the applications in the field of supercapacitors [ 18 , 19 ] and sensors [ 20 ] were reported, while in the case of (ii) the POPD/carbon nanotube composites, the main applications were as (a) sensorial platforms for detection of glucose [ 21 ], meldonium [ 22 ], paraquat [ 23 ], pentose [ 24 ] and ampicillin [ 25 ], (b) corrosion protection layers [ 26 ] and (c) as active materials in rechargeable lithium batteries [ 27 ] and supercapacitors [ 28 ]. Special attention was given to blends consisting of conducting and insulating polymers such as POPD/poly(vinyl alcohol), applications in the sensors field being reported in this particular case [ 29 ].…”

“…All these applications were possible as a consequence of good knowledge of the optical and structural properties of these materials. In this context, the main experimental techniques used to evidence the optical and structural properties were: scanning electron microscopy (SEM), Raman scattering, Fourier-transform infrared (FTIR) spectroscopy, photoluminescence, X-ray diffraction, UV-VIS spectroscopy and transmission electron microscopy [ 13 , 17 , 21 , 24 ].…”