β-Cyclodextrin-PANI decorated pencil graphite electrode for the electrochemical sensing of morin in almonds and mulberry leaves

Abstract

Morin (3,2,4,5,7-pentahydroxyflavone) is one of the natural flavonoids which is present in a variety of fruits and herbs. β-cyclodextrin (β-CD) and polyaniline (PANI) decorated Pencil graphite electrode (PGE) has been successfully used as a sensitive and conducting electrode for the determination of morin. The hydroxyl groups of β-CD attract the analyte towards the modified electrode through hydrogen bonding. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques were employed to study the electrochemical properties of the modified electrodes. The enhanced surface roughness of β-CD-PANI/PGE has resulted in the increase of electrocatalytic activity of electrode towards the analyte. Opitical profilometric studies were performed to evaluate the surface roughness of electrodes and differential pulse votammetry (DPV) was used for the quantitative analysis of morin. Scanning electron microscopy (SEM), Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy were carried out to know the physicochemical characteristics of the modified electrodes. The experimental conditions such as scan rate, pH and concentration were optimized. The electrochemical process was found to be adsorption controlled and irreversible from scan rate studies. Under optimal conditions, the linear dynamic range for the quantification of morin was found to be 1.17-32 nM. The low detection limit (0.38 nM) indicates ultrasensitivity of the proposed method. The suggested method has been effectively employed for the determination of morin in almonds and mulberry leaves.

Non-enzymatic electrochemical determination of salivary cortisol using ZnO-graphene nanocomposites

“…The electrode surface area was then calculated by means of the Randles–Sevcik eqn (6) using the slopes, concentration, and diffusion coefficient ((6.70 ± 0.02) × 10 −6 cm 2 s −1 ). 34 i p = 2.69 × 10 5 AD o 1/2 n 3/2 ν 1/2 C where, A represents electroactive surface area (cm 2 ), D o is the diffusion coefficient (cm 2 s −1 ), n : electrons transferred in the reduction–oxidation reaction ( n = 1), C : concentration of the redox couple in the bulk solution (mol cm −3 ) and ν : scan rate (V s −1 ). The electroactive surface area of modified and bare electrodes was found to be 4.90 cm 2 (ZnO/GR/PGE), 2.30 cm 2 (GR/PGE), and 1.12 cm 2 (bare PGE).…”

A facile and economic electrochemical sensor for methylmalonic acid: a potential biomarker for vitamin B12 deficiency

“…An anionic surfactant, SDS, was used for better adherence of PEDOT to the electrode surface, enhancing the solubility associated with the EDOT in an aqueous acidic medium, and influencing the rate of electropolymerization. 18 The electrodeposition process was carried out using 25 consecutive potential cycles ranging from −1.9 V to 1.9 V with a scan rate of 0.05 V s −1 (Fig. S1, ESI†).…”

“…17 Besides this, PGEs also offer a renewable surface which is much more facile and rapid as compared to the polishing procedures required in the case of their solid counterparts, such as glassy carbon electrodes, whose surface renewal plays a paramount role because redox reactions at the electrode surface may bring changes in the GCE's surface properties. 18,19 The modification of PGE using a conducting polymer can further improve the physico-chemical properties of the bare electrode.…”