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Purpose: The novel sodium dodecyl sulfate modified carbon nanotube paste electrode (SDS/CNTPE) was used as a sensitive sensor for the electrochemical investigation of L-tyrosine (TY).Methods: The electrochemical analysis of TY was displayed through cyclic voltammetry (CV)and differential pulse voltammetry (DPV). The surface morphology of SDS/CNTPE and barecarbon nanotube past electrode (BCNTPE) was reviewed trough field emission scanning electronmicroscopy (FESEM).Results: The functioning SDS/CNTPE shows a voltammetric response with superior sensitivitytowards TY. This study was conducted using a phosphate buffer solution having neutral pH(pH=7.0). The correlation between the oxidation peak current of TY and concentration of TYwas achieved linearly in CV method, in the range 2.0×10-6 to 5 ×10-5 M with the detection limit729 nM and limit of quantification 2.43 μM. The investigated voltammetric study at SDS/CNTPEwas also adopted in the examination of TY concentration in a pharmaceutical medicine as a realsample with the recovery of 97% to 98%.Conclusion: The modified electrode demonstrates optimum sensitivity, constancy, reproducibility,and repeatability during the electrocatalytic activity of TY.

Intense present work is directed on the fabrication and application of Poly (serine) modified graphite carbon nanotube composite paste electrode (PSR/CNTPE) for determining the Riboflavin (RF). The surface qualities of the projected sensor were observed by Field Emission Scanning Electron Microscopy (FE-SEM) and the conductivity by Electrochemical Impedance Spectroscopy (EIS) method. The electrochemical redox activity of the PSR/CNTPE to RF was investigated through Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Outcomes displays that Poly (serine) in CNTPE enhanced the catalytic performance of the electrode towards the redox reaction of RF. The voltammetric response of PSR/CNTPE exhibited linear dependence for extended concentration range of RF from 6 μM to 50 μM with lower detection limit of 3.4 × 10 À 8 M.The PSR/CNTPE revealed to be reproducible, highly stable and successfully validated for the pharmaceutical, beverage and milk samples. The fabricated electrode was conducive and displayed two well-separated oxidation signals for the solution containing two vitamins RF and Folic Acid (FA). The projected sensor is an adequate candidate for electrochemical sensing of RF.

A Sodium lauryl sulfate modified carbon nanotube paste electrode (SLSMCNTPE) was fabricated for the electroanalysis of Riboflavin (RF) in phosphate buffer solution (PBS) at pH, 7.0 by cyclic voltammetry (CV). The electrode was found to be a very sensitive tool for detection of RF; it was shown that SLSMCNTPE yields a high current response towards RF as compared to the bare carbon nanotube paste electrode (BCNTPE). Key parameters were optimized for RF determination. The effects of surfactant concentration, pH, scan rate and concentration of RF on the oxidation peak current values were determined. The RF oxidation peak appeared at −440 mV and reduction peak at −575 mV vs. saturated calomel electrode (SCE). The SLSMCNTPE revealed good repeatability, reproducibility, stability, high electrochemical sensitivity in its voltammetric response and a detection limit of 9.25×10‐8 M.

Suitable electro-catalytic technique is established for the selective determination of Indigo Carmine (IC) at poly(arginine) modified carbon paste electrode (PAMCPE). The surface morphological study of the electrode is done through Field Emission Scanning Electron Microscopy (FESEM). The different parameters such as concentration, pH and scan rate on the electrode response are studied. The individual and simultaneous performance of IC and Riboflavin (RF) is carried out through differential pulse voltammetry. The electrocatalytic response of the sensor varied with the concentration of IC in the range from 2×10-7 M to 1×10-6 M and 1.5×10-6 M to 3.5×10-6 M is observed. Limit of detection (LOD) and the limit of quantification (LOQ) is found 2.53×10-8 M and 8.43×10-8 M respectively. The developed PAMCPE successfully shows better electrochemical response towards IC when compared with BCPE. Preparation and characterization of both the electrodes is simple and easier. This has derived a standard method for the determination of IC in real samples.

Objective: A poly niacin (NN) modified graphite paste electrode was prepared through a simple electrochemical polymerization route for the determination of Riboflavin (RF) Methods: Electropolymerization technique was used for the preparation of a modified electrode. The electrochemical impedance spectroscopy (EIS) method was used to study the surface behaviors and conductivity of the bare and modified electrodes. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used to study the electrochemical behavior of RF using 0.2 M PBS of 7.5 pH. Results: Poly niacin modified graphite paste electrode (PNNMGPE) provides more affinity towards RF detection with high sensitivity and selectivity over bare graphite paste electrode. RF calibration curve was obtained by LSV between 5.0 µM to 65.0 µM with 0.782 µM limit of detection (LOD) and 2.7608 µM limit of quantification (LOQ), respectively. Selective analysis of RF in the presence of ascorbic acid (AA) and dopamine (DA) was performed at PNNMGPE by the LSV method. Conclusion: The developed PNNMGPE was tested for RF analysis in a multivitamin tablet with good results. Furthermore, the developed electrode shows good stability and reproducibility.

Present work describes the electrochemical sensing and determination of phenolic compound (Phloroglucinol) using non-ionic surfactant Octyl phenol ethoxylate modified carbon nanotube paste electrode (OPEMCNTPE) in PBS (0.1 mol, pH 6.0) by Voltammetric method. The developed electrode was characterized by field emission scanning electron microscope (FE-SEM) and cyclic voltammetric (CV) studies. The OPEMCNTPE shows an exceptional catalytic impact towards the electro-oxidation of Phloroglucinol (PL) in contrast to the bare carbon nanotube paste electrode (BCNTPE). The rise in the concentration of PL is directly proportional to PL anodic peak current in the linear working range 10-90 μmol with a small detection limit (LOD) 0.71 μmol. This method was utilized for the estimation of PL in the water and blood serum samples.