Fourier Transform Continuous Cyclic Voltammetry Research Articles

Study of catalase reversibility during multiple injections of H2O2 using online measurement by FFT continuous cyclic voltammetry

This work presents a new method for the determination of catalase activation reversibility upon injection of different concentrations of hydrogen peroxide (H2O2) based on fast Fourier transformation continuous cyclic voltammetry (FFTCCV). The spectroscopic and cyclic voltammetric data demonstrated that catalase could rapidly decompose H2O2 at concentrations below 40 mM. Also, the catalase activity gradually decreased at higher concentrations of H2O2. In addition, the calculated kinetics model of suicide inhibition demonstrated that the catalase irreversibility was triggered at the concentration of 80 mM. FFTCCV data by multiple injections of H2O2 revealed that the catalase activity could be recovered at 10, 20, 40, and 60 mM after 6, 4, 3, and 2 injections of H2O2, respectively. H2O2 at concentrations above 40 mM was not fully decomposed and remained in the solution after the catalase reaction. The maximum reversibility of the catalase activity was observed for the concentration of 10 mM, when H2O2 concentration drastically decreased within a few seconds of the reaction. Our data shows that the FFTCCV method can be recruited to monitor and evaluate enzymatic reactions.

Supercapacitive evaluation of carbon black/exfoliated graphite/MnO2 ternary nanocomposite electrode by continuous cyclic voltammetry

A new ternary nanocomposite was prepared by using MnO2, carbon black (CB), and exfoliated graphite (EG) through a sonochemical method. In this process, the MnO2 nanoparticles was anchored on the mixture of CB and EG to maximize the specific capacitances of these materials. Structure and morphology of the CB/EG/MnO2 nanocomposites were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the CB/EG/MnO2 nanocomposites with different content of MnO2 were studied by cyclic voltammetry (CV), fast Fourier transformation continuous cyclic voltammetry (FFTCCV) technique, galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS). The best nanocomposite electrode displayed specific capacitance of 364 F g−1 at the scan rate of 2 mV s−1 in 0.5 M Na2SO4 aqueous solution, which is higher than pure MnO2 (289 F g−1). The capacitance stability of the nanocomposite electrode was studied by FFTCCV at the scan rate of 500 mV s−1. The result shows that after recording 4000 CVs, the specific capacitance of the nanocomposite decline only 5%. Furthermore, the nanocomposite electrode showed higher energy density than MnO2 electrode.

Theoretical and Electrochemical Study of Carbon Steel Corrosion Inhibition in the Presence of Two Synthesized Schiff Base Inhibitors: Application of Fast Fourier Transform Continuous Cyclic Voltammetry to Study the Adsorption Behavior

Theoretical and Electrochemical Study of Carbon Steel Corrosion Inhibition in the Presence of Two Synthesized Schiff Base Inhibitors: Application of Fast Fourier Transform Continuous Cyclic Voltammetry to Study the Adsorption Behavior

Using fast Fourier transformation continuous cyclic voltammetry method for new electrodeposition of nano-structured lead dioxide

In this work, a new electrochemical method based on fast Fourier transformation continuous cyclic voltammetry (FFTCCV) technique is introduced for electrodepositing of nano-structured PbO2. During the electrodepositing, a special potential waveform, consisted of a potential step and a potential ramp, was continuously applied on a Pt disk electrode. Various parameters such as potential scan rate, and potential of step were optimized to obtain higher capacity and stability for the formed lead oxide layer. Depend on the potential waveform condition, the morphology and connectivity of the oxide film was changed. The energy storage ability of the prepared lead acid batteries shows a close relation with the morphology of cathode materials. Maximum current efficiency was observed when the potential scan rate reaches to 5Vs−1. The electrode surface was characterized by SEM. The results showed the high surface area as well as high connectivity between particles resulted at optimum scan rate. Analysis of FFTCCV data of obtained PbO2 in H2SO4 revealed that the electrocatalytic properties, and as well stability of PbO2 layer amplified by increasing scan rates up to an optimum value. In addition, a larger over potential for oxygen evolution reaction was also observed for the electrodes by application of this method.

Monitoring of Anti Cancer Drug Letrozole by Fast Fourier Transform Continuous Cyclic Voltammetry at Gold Microelectrode

AbstractA continuous cyclic voltammetric study of letrozole at gold microelectrode was carried out. The drug in phosphate buffer (pH 2.0) is adsorbed at −200 mV, giving rise to change in the current of well‐defined oxidation peak of gold in the flow injection system. The proposed detection method has some of advantages, the greatest of which are as follows: first, it is no more necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. Signal‐to‐noise ratio has significantly increased by application of discrete Fast Fourier Transform (FFT) method, background subtraction and two‐dimensional integration of the electrode response over a selected potential range and time window. Also in this work some parameters such as sweep rate, eluent pH, and accumulation time and potential were optimized. The linear concentration range was of 1.0×10−7−1.0×10−10 mol/L (r=0.9975) with a limit of detection and quantitation 0.08 nmol/L and 0.15 nmol/L, respectively. The method has the requisite accuracy, sensitivity, precision and selectivity to assay letrozol in tablets. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the letrozol were considered.

Separation and Determination of Medium Lanthanides: A New Experiment with Use of Ion-Exchange Separation and Fast Fourier Transform Continuous Cyclic Voltammetry

Separation and Determination of Medium Lanthanides: A New Experiment with Use of Ion-Exchange Separation and Fast Fourier Transform Continuous Cyclic Voltammetry

Light Lanthanides Determination by Fast Fourier Transform Continuous Cyclic Voltammetry after Separation by Ion-exchange Chromatography

Light Lanthanides Determination by Fast Fourier Transform Continuous Cyclic Voltammetry after Separation by Ion-exchange Chromatography

Monitoring of Methyldopa by Fast Fourier Transform Continuous Cyclic Voltammetry at Gold Microelectrode

AbstractA continuous cyclic voltammetric study of methyldopa at gold micro electrode was carried out. The drug in phosphate buffer (pH 2.0) is adsorpted at 400 mV, giving rise to change in the current of well‐defined oxidation peak of gold in the flow injection system. The proposed detection method has some of advantages, the greatest one of which are as follows: first, it is no more necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. Signal‐to‐noise ratio has significantly increased by application of discrete Fast Fourier transform (FFT) method, background subtraction and two‐dimensional integration of the electrode response over a selected potential range and time window. Also in this work some parameters such as sweep rate, eluent pH, and accumulation time and potential were optimized. The linear concentration range was of 1.0×10−7−1.0×10−11 mol·L−1 (r=0.9975) with a limit of detection and quantitation 0.004 nmol·L−1 and 0.03 nmol·L−1, respectively. The method has the requisite accuracy, sensitivity, precision and selectivity to assay methyldopa in tablets. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the methyldopa were considered.

Application of Adsorptive Voltammetry for the Detection of Sub-nano Molar Cyclizine in Biological Fluids and Tablets Using Fast Fourier Transform Continuous Cyclic Voltammetry in a Flowing System

An easy and fast Fourier transform continuous cyclic voltammetric technique (FFTCV) for monitoring of ultra trace amounts of cyclizine in a flow-injection system has been introduced in this work. The potential waveform, which was applied continuously on an Au disk microelectrode (12.5 microm in radius) consisted of the potential steps for cleaning, accumulation and potential ramp. The proposed detection method has some advantages, the greatest of which are as follows: first, it is no longer necessary to remove oxygen from the analyte solution and second, this is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The detection limit for cyclizine was 1.8 ng ml(-1). The relative standard deviation (RSD) of the proposed technique at 5.0 x 10(-7) was 2.0 for 10 runs. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the cyclizine were considered. The proposed method was applied to the determination of cyclizine in a pharmaceutical preparation.

A new method for the determination of loratadine at an Au microelectrode in flowing systems with the use of fast continuous cyclic voltammetry

This research presents a new method for the fast monitoring of loratadine in pharmaceutical formulation. The method employs the fast Fourier transformation continuous cyclic voltammetry (FFTCV) at a gold microelectrode in a flowing-solution system. Three considerable advantages of the technique are demonstrated. First, there is not any requirement for the oxygen removal from the test solution; second, a subnanomolar detection limit is gained; and, finally, the speed of the method for the determination of a compound is in a broad range of chromatographic methods. A special computer-based numerical method is also introduced for the calculation of the analyte signal and noise reduction. The electrode response was calculated in accordance with the partial and total charge exchanges on the electrode surface after the background current subtraction from that of the noise. The integration range of the currents was set for all potential scan ranges, including the oxidation and reduction of the Au surface electrode in order to obtain a sensitive determination. The objective of the performed experiments was to study the effects of different parameters on the method sensitivity. It was concluded that the method had a linear concentration range of 40–765000 pg/mL (r = 0.999) with a limit of detection and quantitation of 12 and 40 pg/mL, respectively. For the achievement of these optimum results, the parameter values were set to 80 V/s for the scan rate, 0.7 s for the accumulation time, 300 mV for the accumulation potential, and 2 for the pH.

Development a New Method for the Determination of Chloropromazine in Trace Amounts by Fast Fourier Continuous Cyclic Voltammetry at an Au Microelectrode in a Flowing System

AbstractIn this study a new technique has been developed for the determination of chloropromazine in flow‐injection systems. The technique, named fast Fourier transformation continuous cyclic voltammetry (FFTCV), basically illustrates the benefits of sensitivity, selectivity, simplicity and low detection limit.It is also important to refer to the positive points, presented only by the use of this technique. Firstly, it is no longer necessary to remove the oxygen from the test solution. Furthermore, the quick determination of any such compound in many chromatographic methods is possible. Thirdly, the corresponding detection limit is of sub‐nanomolar level. Additionally, a special computer based numerical method is also introduced for the calculation of the analyte signal and noise reduction. The electrode response was calculated in accordance with the partial and total charge exchanges on the electrode surface, after the background current subtraction from that of noise. The integration range of currents was set for all the potential scan ranges, including oxidation and reduction of Au surface electrode, to obtain a sensitive determination.The performed experiments aimed at measuring the effects of different parameters on the method sensitivity. In the end of these measurements, it was concluded that the method was linear for the concentration range of 0.32–31900 pg/mL (r = 0.996) with a limit of detection and quantitation 0.1 and 0.32 pg/mL, respectively. For the achievement of these optimum results, the parameter values were set to 100 V/s for the scan rate, 0.4 s for accumulation time, 800 mV for accumulation potential and 2 for the pH.

Application of Adsorptive Stripping Voltammetry for the Nano‐Level Detection of Tramadol in Biological Fluids and Tablets Using Fast Fourier Transform Continuous Cyclic Voltammetry at an Au Microelectrode in a Flowing System

A novel adsorptive fast Fourier transform cyclic voltammetry (AFFTCV) technique for the fast determination of tramadol in flow‐injection systems has been introduced in this work. The potential waveform, consisting of the potential steps for cleaning, stripping, and potential ramp, was continuously applied on an Au disk microelectrode (with a 12.5 µm in radius). The proposed detection method has some advantages, the greatest of which are as follows: first, it is no more necessary to remove oxygen from the analyte solution and second, it is a very fast and appropriate technique for determination of the drug compound in a wide variety of chromatographic analysis methods. The influences of pH of eluent, accumulation potential, sweep rate, and accumulation time on the determination of the tramadol were considered. The method was linear over the concentration range of 1.5–900,000 pg/ml (r=0.9968) with a limit of detection and quantitation 0.32 and 1.5 pg/ml, respectively. The method has the requisite accuracy, sensitivity, precision, and selectivity to assay tramadol in tablets and in biological fluids.

Fast Fourier Transform Continuous Cyclic Voltammetry Development as a Highly Sensitive Detection System for Ultra Trace Monitoring of Thiamine

In this work, a highly sensitive method for the fast monitoring of thiamine hydrocholoride in flow‐injection systems has been developed. The fast Fourier transform continuous cyclic voltammetry (FFCV) in flowing solution as a detection system was applied for the very fast monitoring of thiamine in its pharmaceutical formulations. This technique is very simple, precise, accurate, time‐saving and economical, compared to all previous reported methods. The effects of various parameters on the sensitivity of the detection system were considered. The best condition was obtained within the pH value of 2, and scan rate value of 25 V s−1, accumulation potential of −400 mV, and accumulation time of 0.6 s. The proposed method has some advantages over other reported methods such as, there is no need for the removal of oxygen from the test solution, has a sub‐nanomolar detection limit, and finally the method is fast enough for the determination of any such compound, in a wide variety of chromatographic methods. This research also introduces a special computer‐based numerical method, for the calculation of the analyte signal and noise reduction. The electrode response was calculated based on partial and total charge exchanges on the electrode surface after subtracting the background current from that of noise. To obtain a sensitive determination, the integration range of currents was set for all the potential scan ranges, including oxidation and reduction of the Au surface electrode, while performing the measurements. The potential waveform, consisting of the potential steps for cleaning, accumulation and potential ramp of analyte, was applied on an Au disk microelectrode (12.5 µm in radius) in a continuous way. The detection limit of the method for thiamine was 1.0×10−12 M. The relative standard deviation of the method at 1.0×10−8 M was 2.2% for 8 runs.

Development of fast Fourier transformation continuous cyclic voltammetry as a highly sensitive detection system for ultra trace monitoring of penicillin V

Fast continuous cyclic voltammetry was used as a detection method for penicillin V in a flow injection system. Additionally, a special computer-based numerical calculation method (using fast Fourier transformation) providing enhancement of the analyte signal and noise reduction is introduced here. During the measurements, the potential waveform (consisting of the potential steps of cleaning, stripping, and the potential ramp) was continuously applied to an Au disk microelectrode (12.5 μm in radius). In particular, the effects of accumulation potential, sweep rate, and delay time on the sensitivity and selectivity of the method were investigated. Eventually, the stripping time was found to be less than 300 ms, the detection limit of the method was 7.0 × 10 −12 M, and the associated relative standard deviation at 5.0 × 10 −6 M penicillin V was 2.3 for eight runs.

A sub-second fast Fourier transform-adsorptive voltammetric technique for the nano-level determination of guthion at a gold microelectrode in flowing solutions

This research demonstrates the quick guthion monitoring with the help of a sensitive method called fast Fourier transformation continuous cyclic voltammetry (FFTCV). Fortunately, FFTCV illustrates the benefits of precision, determination speed, cost-effectiveness, accuracy and simplicity, in comparison with formerly reported techniques. In particular, this method was applied to a gold microelectrode in flowing solutions to detect the guthion concentration in its formulations. The effects of several parameters were examined regarding the sensitivity of the method. After a series of experiments, the detection limit of the method was found to be equal to1.27 pg/mL, when the optimum conditions were imposed, which is a scan rate value of 40 V/s, an accumulation time of 0.4 s, an accumulation potential of 0 mV and a pH value of 2. During the measurements performance, the integration range of currents included all the potential scan ranges, even the oxidation and reduction of the Au surface electrode, for the achievement of a sensitive determination. Then, the potential waveform, consisting of the potential steps for cleaning, accumulation and the step for the potential ramp, was applied to an Au disk microelectrode in a continuous way. It is also important to refer to the positive points, presented only by the use of this technique. Firstly, it is no longer necessary to remove the oxygen from the test solution. Furthermore, the quick determination of any such compound in many chromatographic methods is possible. Thirdly, the corresponding detection limit is of nanomolar level.

Fast Monitoring of Nano‐Molar Level of Gentamycin by Fast Fourier Transform Continuous Cyclic Voltammetry in Flowing Solution

A novel method for the determination of gentamycin in flow‐injection systems has been developed in this work. The principal advantages of this method are that it is rapid, simple, and possesses low detection limit. Some investigations were also done to find the effects of various parameters on the sensitivity of the proposed method. The conditions producing the performance were the pH value of 2, the scan rate value of 350 V/s, accumulation potential of (100 mV), and accumulation time of 0.9 s. Some of the advantages of the proposed method are: the removal of oxygen from the test solution is not required anymore, the detection limit of the method is sub‐nanomolar, and finally, the method is fast enough for determination of such compounds, in a wide variety of chromatographic methods. We also introduce a special computer‐based numerical method for calculation of the analyte signal and noise reduction. After subtracting the background current from noise, the electrode response was calculated, based on partial and total charge exchanges at the electrode surface. The integration range of currents was set for all the potential scan ranges, including oxidation and reduction of the Au surface electrode, to obtain a sensitive determination. The waveform potential was continuously applied on an Au disk microelectrode (12.5 µm in radius). Detention limit of the method for gentamycin was found to be 1.0×10−9 M. For 10 runs, the relative standard deviation of the method at 1.0×10−7 M was 2.1%.