Computational Design and Application of Molecularly Imprinted/MWCNT Based Electrochemical Sensor for the Determination of Silodosin

Abstract

A novel molecularly imprinted polymer (MIP) based electrochemical sensor was developed for differential pulse voltammetric detection of silodosin (SLD), used for enlarged prostate (benign prostatic hyperplasia; BPH) treatment. A computational design was first applied for optimization of the molar ratio between silodosin (SLD, template): Methacrylic acid (MAA, functional monomer), based on which five polymeric ratios were prepared followed by testing the amount of crosslinker (ethylene glycol dimethacrylate (EGDMA)), imprinting and rebinding efficiency of the polymer. The ratio 1:4:20 was found to have the highest binding capacity for SLD, and thus, was used as a modifier for the development of modified carbon paste electrodes in presence of multiwalled carbon nanotubes (MWCNT). The sensor was electrochemically characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements and morphologically using SEM, TEM and BET and its performance was optimized in terms of amounts of MIP, MWCNT, pH and other electrochemical parameters. A linear response range of 1.0 × 10 À 12 -1.0 × 10 À 3 M SLD with a detection limit (S/N = 3) of 1.0 × 10 À 13 M was shown. Finally, the MIP-modified carbon paste sensor was successfully used to determine SLD in pure solutions, pharmaceutical formulations and spiked serum and urine samples.

Application of a Gold /Poly(Congo Red) Modified Electrochemical Sensor Toward Fast and Reliable Detection of the Oxazolidinone Fungicide Famoxadone in Vegetables

“…Figures 8C, 8D shows a linearity between peak current and square root of scan rate for bare GCE and AuNPs/ poly(CR)/GCE, which indicates that the process is diffusion controlled as expected for this catalytic system with two regression equations: І p = 10.391 + 4.674 υ 1/2 with (R 2 = 0.984) and І p = −7.166 + 8.081 υ 1/2 with (R 2 = 0.999) for bare GCE and AuNPs/ poly(CR)/GCE, respectively. 35,53,54 The effective surface area of electrodes was calculated using Randles-Sevcik equation Eq. 2.…”

“…8E was shown to be linear with a regression equation presented as: Log[І p ] = 0.817 + 0.52 log [υ] with correlation coefficient (R 2 = 0.998) and the slope was found to have a value 0.52 which is in quite close to the theoretical value of 0.5 which indicated a diffusion-controlled process. [53][54][55] Interference studies.-The performance of AuNPs/poly(CR) towards FAM in the presence of other classes pesticides, Cymoxanil, Fluopicolide, Azoxystrobin, Chloropyrifos, Imidacloprid, Penconazole, Kasugamycin, that might exist in the same environment was examined. DPV was performed for solutions containing 1 μM FAM mixed with different ratios 1:1, 1:10 and 1:100 of the tested interferents As given in Table I, it is clear from the given data that no significant changes (±5%) were recorded in the peak currents of FAM oxidation at the different tested ratios, which revealed that the AuNPs/Poly(CR)/GCE has acceptable selectivity with respect to FAM.…”

Application of Molecularly Imprinted Electrochemical Sensor for Selective Non-Labelled Detection of Acetamiprid Insecticide in Fruits

“…The slope was found to be 0.43 which is close to the theoretical of 0.5, confirming that an adsorption-diffusion controlled process occurred on the surface of MIP/MW-CNT/CPE. [56][57][58][59] Randle-Sevcik Eq. 5 correlating, the slope of the relation between square root of the scan rate (υ 0.5 mV/s 0.5 ) and anodic peak current (I a μA) for 2.5 mM FCN in 0.1 M KCl solution was used for calculating the total surface area of the final sensor 60,61 Where: υ 1/2 is square root of the scan rate by mV/s 0.5 , C 0 is the concentration of the probe (2.5 mM), D 0 is the diffusion coefficient for FCN = 7.6 × 10 −6 cm 2 s −1 , A is the surface area of the electrode by cm 2 , and n is the number of transferred electrons for 1 mM FCN (n = 1).…”

“…It is noteworthy to mention that the smallest charge transfer resistance (R ct = 191.9 Ω) was recorded for MIP/MW-CNT/ CPE electrode, due to the synergistic effect of both high electroactivity of multi-walled carbon nanotube and recognition cavities of molecularly imprinted polymer, enhancing the transfer of FCN probe through electrode surface. 44,58 Calibration function, repeatability, and reproducibility.-DPV measurements were applied for the stepwise characterization of the sensor modification, using 2.5 mM FCN in 0.1 M KCl solution at potential range (−0.2 to 0.8) V and scan rate 50 mV s −1 . At optimum conditions for sensor's operation, the relationship between the differential pulse voltammetric current response of FCN at different concentrations of ACP was studied as shown in Fig.…”

Design and application of molecularly imprinted electrochemical sensor for the new generation antidiabetic drug saxagliptin

“…The physical and catalytic properties of CNTs turned them ideal as composite modifiers in polymeric films, solar and fuel cells and electrochemical sensors. They were also reported to exhibit excellent chemical, thermal, and mechanical properties flexibility, and electrical conductivity which promotes their catalytic activity and charge transfer enhancement especially when incorporated in carbon paste electrodes [54][55][56]. Recently, MWCNT were used as modifiers in different electrochemical sensors for the detection of many analytes including: rutin [57], food azo dyes [58], pesticides [59] and vitamin D3 [60].…”