Search

Creatine is a well-known member of supplement family and is widely preferred by consumers for therapeutic applications, muscle strength, and energy recovery. This study describes a new concept, which is based on a simple, one-step, and non-enzymatic creatine detection system on the Pt electrode. The creatine content of food supplements was determined using an elemental analyzer, and five different supplements were separated in terms of creatine. Three supplements were investigated as creatine sources, and the other two supplements were considered as branched-chain amino acid sources. For the electrochemical detection of creatine, cyclic voltammetry and square-wave voltammetry techniques were used. Graphene oxide and carbon nanotube-modified surfaces were applied in addition to bare Pt surface; however, bare Pt surface was found to be superior to the modified surfaces. Creatine was successfully detected using the proposed Pt electrode, and the limit of detection was calculated to be 36.0 mu g L-1. The obtained selectivity allowed performing a voltammetric comparison of creatine and branched-chain amino acid supplements. Real sample analysis was performed by analyzing milk powder; however, milk powder supplied only 32.4% of creatine content. This study presents a new method for detection of food supplements without the need for modification, high-cost, or pretreatment process.

Topological phononic states with nodal lines not only have updated our knowledge of the phases of matter in a fundamental way, but also have become a major frontier research direction in condensed matter physics. From a mathematical perspective, nodal line phonons can be divided into open and closed types. The present attempt is a report on the coexistence of such open and closed nodal line phonons in two realistic solids, CoAsS and Na

Topological phononic states with nodal lines not only have updated our knowledge of the phases of matter in a fundamental way, but also have become a major frontier research direction in condensed matter physics. From a mathematical perspective, nodal line phonons can be divided into open and closed types. The present attempt is a report on the coexistence of such open and closed nodal line phonons in two realistic solids, CoAsS and Na2CuP, based on first-principles calculations. Furthermore, it is shown that the closed and the open nodal line states in CoAsS and Na2CuP have touching points and can form a complex nodal structure phonon in a momentum space. Due to the topologically non-trivial behavior of the complex nodal structure in both phonons, evident phononic surface states occur in the projected surfaces of both materials. In this way, these states, arising from the projected crossing points, can benefit experimental detection in follow-up studies. It has been stated that the open and closed nodal line states are formed by the crossings of two phonon branches and, hence, these two types of nodal line phonons are coupled with each other. The results obtained here could be considered as a breakthrough in clearly demonstrating the coexistence of the open and closed nodal line states in phonons and, for this reason, may inspire researchers seeking materials with such topological states in other bosons, such as photons. © 2022 The Royal Society of Chemistry.

Determination of ?-lactoglobulin in milk products is very important because ?-lactoglobulin is the main ingredient in whey-based protein powders. However, ?-lactoglobulin is a dangerous food allergen. On such an occasion, the determination of ?-lactoglobulin is coming into prominence and electrochemistry is a good alternative for this purpose because of its simple, economic and rapid response. In this work, a graphene oxide modified pencil graphite electrode is developed to determine ?-lactoglobulin based on the current signal of known concentration of hydrogen peroxide. Cyclic voltammetry technique is performed to obtain the electrochemical behavior of ?-lactoglobulin. Linear range, limit of detection and limit of quantification were calculated according to the calibration curve of various amounts of ?-lactoglobulin. Ultraviolet–visible spectroscopy technique is also used to investigate the absorption behavior of ?-lactoglobulin in various biological macromolecules including whey proteins. The proposed graphene oxide modified pencil graphite surface is successfully applied to determine ?-lactoglobulin in real milk sample, so a new methodology based on a newly developed electrochemical technique is described as a promising alternative in diary products. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

In this work, two independent methods including inductively coupled plasma-mass spectrometry (ICP-MS) and electrochemistry were combined to analyze and treat drinking water. ICP-MS is a highly sensible and multi-element capable method, so heavy metal ions content of drinking water samples coming from various resources was determined using ICP-MS. At the same time, average, median and limit of detection (LOD) of elements existing in water samples were obtained to compare regional variations between resources. 10 different elements (Al, Cr, Mn, Fe, Ni, Se, Cd, Sb, Ba and Pb) were detected in rural, well and urban water. Only Pb level (18.73 mu g L-1) exceeded the standard level (15.00 mu g L-1) in well water, so an electrochemical removal procedure was developed. To remove Pb present in drinking water, electrochemical techniques (cyclic and square wave voltammetry) were used and nano-dimensional new surfaces (graphene oxide and nanotubes modified gold and platinum) were created to obtain specific Pb behavior (- 0.20 V vs. Ag/AgCl). After removal, LOD levels of the detected elements were ranged between 0.03 and 5.73 mu g L-1, and Pb level was lowered to 8.09 mu g L-1 in well water. In this way, electrodeposition was successfully applied to achieve metal ion-free water samples., Ege University Scientific Research Project of Turkey [FKB-2019-20505], This work was supported and granted by the Ege University Scientific Research Project of Turkey (FKB-2019-20505).

Arsenic is one of the most abundant elements on the earth and possesses metallic as well as nonmetallic properties. Besides arsenic is very toxic and carcinogenic, it is found in nature both naturally and anthropogenically. Inorganic arsenic species existing in water are arsenite (As3+) and arsenate (As5+). Arsenic toxicity is a global problem because arsenic contamination is naturally coming from water resources. The maximum admissible concentration of arsenic must not exceed 10 µg L–1, so the determination of the total arsenic amount regardless of its species is very important. In this work, the presence of arsenic was electrochemically determined using cyclic, square wave and differential pulse voltammetry, and a spectroscopic determination method including induc-tively coupled plasma-mass spectrometry (ICP-MS) was applied. A combination of ICP-MS as a sen-sitive, multi-element capable and reliable method with electrochemistry as a simple, cost-efficient and powerful method was performed to determine and remove arsenic for the first time. Newly modified nano-dimensional surfaces were developed to obtain specific arsenic behavior and effective electrodeposition of arsenic in the removal process. With the water supply research, regional differences in drinking waters were discovered, and different kinds of drinking water samples were put into a common form in terms of drinkable, arsenic-free, high-grade standards. © 2021 Desalination Publications. All rights reserved., FKB-2019-20505, This work was supported and granted by the Ege University Scientific Research Project of Turkey (FKB-2019-20505).

An electrodeposition-based process was developed in this work. Electrochemical atomic layer epitaxy (ECALE) and co-deposition methodologies were employed to grow copper (II) sulfide (CuS) and zinc sulfide (ZnS) thin films as photovoltaic semiconductors on polycrystalline gold electrode. The deposition potentials of copper (Cu), zinc (Zn) and sulfur (S) were defined separately by cyclic voltammetry. Thin films were created from an electrolyte containing copper (II) sulfate (CuSO4), sodium sulfur (Na2S) and zinc sulfate (ZnSO4) in ethylenediaminetetraacetic acid (EDTA) using both cyclic voltammetry and bulk electrolysis techniques. The influence of bath temperature at the deposition potential was studied to determine the crystallinity of deposits. From the chronoamperometry results including the transients obtained within the under potential region, the nucleation and growth process of deposits were estimated. In this way, an electrodeposition-based method for CuS and ZnS semiconductors in a comparable basis was improved on polycrystalline gold substrate.

The nonenzymatic detection of glucose has been widely investigated in a variety of fields ranging from biomedical applications to ecological approaches. Among these fields, electrochemical methods have great advantages such as high electrocatalytic ability, high sensitivity, good selectivity and low-cost for the electrooxidation of glucose. Future trends on glucose sensing are nanostructured electrodes depending upon the development of nanotechnology. In this study, an electrochemical and nonenzymatic glucose sensor based on (E)-4-((5-methylthiazole-2-yl)diazenyl)-N-phenylaniline (MDPA)/multi-walled carbon nanotube (MWNT)/pencil graphite electrode (PGE) was performed. Electrochemical measurements were obtained using cyclic voltammetry and square wave voltammetry techniques, and characterization of surfaces was carried out using scanning electron microscope and electrochemical impedance spectroscopy techniques. The modification of PGE was made using MDPA and MWNT, and 10 cycles coating was used to prepare the proposed electrode. The effects of scan rate and pH on the peak potential and the peak current were determined. The limit of detection and linear range were calculated using various concentrations of glucose. The interference study was made using coexisting substances including metal ions such as Al3 +, Cu2 +, Fe3 + and ascorbic acid.

A combination of a novel synthesized azo dye (E)-1-(4-((4-(phenylamino)phenyl)diazenyl) phenyl)ethanone and reduced graphene oxide was used to electrochemically modify the surface of a pencil graphite electrode. The surfaces of the modified electrodes were characterized using electrochemical techniques (cyclic voltammetry and electrochemical impedance spectroscopy) and spectroscopic techniques (scanning electron microscopy and attenuated total reflectance). This azo dye/reduced graphene oxide modified electrode was applied first time for the electrochemical detection of an organophosphorus pesticide, fenitrothion. The modified pencil graphite electrode displayed excellent performance for the detection of fenitrothion. Cyclic voltammetry was used to study the dependence of the scan rate on the peak current and peak potential and to determine the kinetic parameters for fenitrothion. Square wave voltammetry was used to determine the effect of pH on the peak potential and for the sensitive and selective detection of fenitrothion using the modified electrode. Satisfactory results were obtained with the proposed sensor for the analysis of FT in tomato samples.

Sterilization is the certain and absolute decontamination of microorganisms totally from all manner of alive and active species. Sterilization devices used in the sterilization processes are between laboratory and external patient application devices of biomedical device technology, and they are designed to remove equipments from germs. The application potential of hetarilazo indole based azo dyes in the biomedical sterilization are known and azo dyes come into prominence in this class because of simplicity of their synthesis and procurement of low-cost raw materials. In this work, the application potential of a novel synthesized azo dye, ( E )- N -phenyl-4-(thiazole-2-yldiazenyl)aniline was investigated as an indicator in the biomedical sterilization performing the electrochemical and spectroscopic characterizations. The application of indicator was tested by ethylene oxide, hydrogen peroxide and peracetic acid sterilization techniques introducing into various sterilization rolls.

New surfaces were created by modifying gold electrode for electropolymerization of thiophene in aqueous media. The first step in modified electrode production was self assembled monolayer (SAM) coating. Thereby, surfaces with controllable chemical functionalities were obtained. The second step was gold nanoparticle (AuNP) deposition above this coating. Characterization of surfaces was made with electrochemical and spectroscopic methods. In this study, initially, the surface was insulated with inserting Au electrode into 11-mercaptoundecanoic acid (MUA) solution. Conductivity of surface was increased by gold nanoparticle deposition and gold nanoparticle pores were used as a platform for thiophene polymerization. Electropolymerization of thiophene in the aqueous media was achieved with the obtained modified electrode. At the end of study, voltammograms were taken in the 5 mM Fe ( CN ) 6 4 - / 3 - redox probe containing 0.1 M KCl and 0.1 M HClO4 solutions. The characterization of modified surfaces was carried out by Scanning Electron Microscopy (SEM) and Attenuated Total Reflectance (ATR) methods.

An enormous range of possible dyes are available, especially as the starting molecules are readily available and cheap. As other dye classes become less viable from either an environmental or economic reasons, azo dyes come to the forefront. Therefore, electrochemical characterization of a novel synthesized azo dye (E)-1-(4-((4-(phenylamino)phenyl)diazenyl)phenyl) ethanone was achieved for the first time. Cyclic voltammetry, chronoamperometry and square wave voltammetry techniques were used to investigate the electrochemical behavior and electrocatalytic effect of azo dye (E)-1-(4-((4(phenylamino)phenyl)diazenyl)phenyl) ethanone at pencil graphite electrode. Cyclic voltammograms were utilized to determine the effect of scan rate and pH on the peak current and peak potential. Chronoamperometry technique was used to determine diffusion constant, D and the type of adsorption isotherms. The kinetics parameters which were the apparent electron transfer rate constant, k(s) and charge transfer coefficient, a were calculated. Square wave voltammetry was used to verify responses of cyclic voltammetry technique. (C) 2016 Elsevier Ltd. All rights reserved.