Analytical and Bioanalytical Chemistry Research
Volume:8 Issue: 3, Summer 2021

Herein, Piperine, a phytochemical present in Long pepper is quantitatively analyzed via an electrochemical technique using a chemically modified electrode. Mesoporous nanomaterial has been utilized as a base matrix to carry out the experiments. The piperine is isolated from crude Long pepper through a standard procedure. Glassy carbon electrode is chemically modified with mesoporous carbon matrix and isolated piperine designated as (GCE/GMC@piperine). The cyclic voltammetry response gave a perfect redox response of piperine at E’= +0.2 V vs Ag/AgCl at 50 mV s-1in pH 7 PBS. Effect of scan rate and effect of solution pH was studied. Further, it was observed that a change in concentration of piperine is directly proportional to the redox peak current obtained. Therefore, this studies could act as a key for quantitative analysis of Piperine; naturally occurring phytochemical in natural products like Pepper, Long pepper, white pepper etc. This is a prototype study and can be further extended to disposable screen printed electrodes for portable analysis.

Dehydration of alcohols has attracted a great deal of attention owing to its wide application in ‎several medical, pharmaceutical and chemical industries. High separation efficiency, low energy ‎consumption, simplicity and minimum contamination are the main characteristics which make ‎pervaporation (PV) a promising method in the area of alcohol dehydration to provide extremely ‎pure alcohols. Due to their permselectivity and high processability, polymers are the main ‎materials for PV membranes. For this purpose, poly(vinyl alcohol) (PVA) is the most commonly ‎used polymer because of its desired hydrophilicity, flexibility, good film-forming ability and low ‎cost. However, excessive swelling is the main challenge in fabrication of PVA membranes for ‎dehydration application; to overcome this disadvantage, various attempts have been made to ‎modify PVA membranes for separation of water and alcohols. In this paper, various ‎modifications and developments that have been made to improve the PV performance of PVA-‎based membranes for separation of water and alcohols have been reviewed.‎

This study aims to develop a promising electrochemical sensor based on polymer film overoxidation following the electrochemical polymerization of p-aminophenol on a bare glassy carbon electrode (GCE) surface for the voltammetric determination of sumatriptan succinate (SUM). Cyclic voltammetry (CV), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and square wave voltammetry (SWV) were employed to characterize the electroanalytical performance and morphology of the modified electrode. The results indicated a significant improvement in electrode sensitivity to SUM after electrochemical polymerization and overoxidation of poly(p-aminophenol). We also investigated the effect of all effective instrumental and experimental parameters on sensor response. Under the optimum conditions (accumulation for 60 s at 0.055V and pH= 2.0) the electrode SWV response to SUM within the range 1.0-100.0 μmol L-1 with a limit of detection (LOD) of 0.294 μmol L-1 was linear under optimized conditions. We also attempted to evaluate the designed sensor selectivity to different interfering species, suggesting no significant interference. The designed sensor was also used to determine SUM in pharmaceutical preparations and human serum samples with minimal matrix effects, admissible recoveries (99-106), and satisfactory repeatability (1.2-5.1 %RSD). The proposed sensor exhibited admissible repeatability, reproducibility, and stability.

In the present work, combination of unique properties of two nano material compounds, MgO nano paricles (MgO NPs) and multi-wall carbon nanotubes (MWCNT), and electrocatalytic activity of an oxadiazole derivative, 3-(5-(pyridine-4-yl)-1,3,4-oxadiazole-2-ylthio)-4- methylcyclohexa-1,3-diene-1,2-diol; POM, was used to fabricate a sensitive electrode (POM-MgO NPs-MWCNT-CPE) for electrochemical determination of folic acid. The electrochemical treatment of folic acid was studied in phosphate buffer solution (0.1 M, pH 7) by means of common electrochemical techniques such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The sensitive fabricated electrode displayed good operating characteristics such as wide linear range and low detection limit for the determination of folic acid. Using the fabricated electrode, a wide linear dynamic range in concentration range 0.08-650.0 μM, and a limit of detection of 0.02 μM were found. Using the modified electrode, the two well distinguished peaks were recorded at 110.0 and 209 mV for ascorbic acid and folic acid, respectively. Reliability and accuracy of the introduced electrode were studied in pharmaceutical and biological samples.

In this report, a new aptamer-based assay was presented reporting the electrochemical aptasensing for sensing tyrosinamide (Tyr-NH2). This strategy was relied on unbeatable conformational flexibility and specific recognition of aptamers. The tyrosinamide aptamer (Tyr-NH2-aptamer) was immobilized onto the metal-organic frameworks/silver nanoparticles modified glassy carbon electrode and hexacyanoferrate was selected as a probe to monitor interface variations during modification of the electrode and the aptamer conformational change generated by the Tyr-NH2 binding. Results showed that measurements by using electrochemical impedance spectroscopy had linear with the Tyr-NH2 concentrations in range of 0.01-0.25 nM and 0.25-1.15 nM. Detection limit of this system was found to be 2.3 pM. This method was also used to the Tyr-NH2 detection in serum samples successfully. Remarkable simplicity, ease of use and low-cost, make methodology as sensitive analytical system for sensing of the Tyr-NH2 that can be miniaturized. This strategy offers some promising advantages in reliable detection of the Tyr-NH2, which may be helpful in the routine analysis.

Bimetallic nanoparticles have numerous applications in different areas, including catalysis, medicine, optics, and so on. Due to numerous intrinsic disadvantages and potentially toxic chemical procedures, finding nontoxic, green, cost-effective, and eco-friendly approaches for the production of bimetallic nanoparticles is much desired. In this study, Zn NPs, Zn/Fe3O4 NPs, and Zn/Chitosan/Fe3O4 nanocomposites were synthesized via a one-pot procedure by using leave extract of Quercus brantii, in the absence of any dangerous components. The catalytic capacity of the green synthesized Zn/Chitosan/Fe3O4 nanocomposite was considered for the degradation of environmental pollutants, including Congo red (CR), Methylene blue (MB), Cr(VI), and 4-nitrophenol (4-NP). The Zn/Chitosan/Fe3O4 nanocomposites have been morphologically characterized using UV–Vis, SEM, and EDX studies. The antioxidant reducing and antibacterial activities of Zn/Chitosan/Fe3O4 nanocomposites have been considered. Our results showed that this nanocomposite could be reused five times for removal of Congo red (CR), Methylene blue (MB), Cr(VI), and four times for reduction of 4-nitrophenol (4-NP), without substantial reduction in the catalytic capacity. Results showed the high potential catalytic activity of Zn/Chitosan/Fe3O4 nanocomposite for the reduction of organic pollutants.

A liquid chromatographic method was developed and validated to estimate glycopyrrolate (GLP) present in pharmaceutical formulations. The method was developed using a C18 column with a mobile phase involved methanol: phosphate buffer (pH=3.2) (65:35, %v/v) flowing at 1.0ml min-1. GLP was detected at a wavelength of 224nm. The method was found linear over a concentration range of 6-14µg ml-1. Degradation studies proved the chromatographic method specificity. Validation studies postulated method acceptability and suitability for estimating GLP in both bulk as well as injectables. The detection and quantitation limits were 2.5µg ml-1 and 6.0µg ml-1, respectively. Further, method precision was assured (%R.S.D. <2%) employing an experimental design approach using a factorial design. Also, it revealed that analyst skills are of critical importance and may influence the method preciseness. Overall the method was reliable and of optimum quality and possesses the potential of application in routine quality control of dosage forms of GLP and may serve as a basis for future bio-analytical method development purpose.