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This review provides an overview of recent advances in electrochemical sensors for analyte detection in saliva, highlighting their potential applications in diagnostics and health care. The purpose of this paper is to summarize the current state of the field, identify challenges and limitations and discuss future prospects for the development of saliva-based electrochemical sensors.

The paper reviews relevant literature and research articles to examine the latest developments in electrochemical sensing technologies for saliva analysis. It explores the use of various electrode materials, including carbon nanomaterial, metal nanoparticles and conducting polymers, as well as the integration of microfluidics, lab-on-a-chip (LOC) devices and wearable/implantable technologies. The design and fabrication methodologies used in these sensors are discussed, along with sample preparation techniques and biorecognition elements for enhancing sensor performance.

Electrochemical sensors for salivary analyte detection have demonstrated excellent potential for noninvasive, rapid and cost-effective diagnostics. Recent advancements have resulted in improved sensor selectivity, stability, sensitivity and compatibility with complex saliva samples. Integration with microfluidics and LOC technologies has shown promise in enhancing sensor efficiency and accuracy. In addition, wearable and implantable sensors enable continuous, real-time monitoring of salivary analytes, opening new avenues for personalized health care and disease management.

This review presents an up-to-date overview of electrochemical sensors for analyte detection in saliva, offering insights into their design, fabrication and performance. It highlights the originality and value of integrating electrochemical sensing with microfluidics, wearable/implantable technologies and point-of-care testing platforms. The review also identifies challenges and limitations, such as interference from other saliva components and the need for improved stability and reproducibility. Future prospects include the development of novel microfluidic devices, advanced materials and user-friendly diagnostic devices to unlock the full potential of saliva-based electrochemical sensing in clinical practice.

The purpose of this paper is to produce non-conductive copolymers of N-vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKFR) by the electroinduced Ce (IV) polymerization method and the electrochemical oxidization of the formed copolymer to produce their conductive green form. The non-conductive and conductive copolymers were characterized by using Fourier transform infrared, solid-state conductivity and spectroelectrochemical, chronoamperometric, cyclovoltammetric and electrochemical impedance spectroscopic measurements.

The chronoamperometric electropolymerization of white, insulator form of the copolymer of NVCz and MEKFR (copolymer 1) on to Pt electrode was carried out and the green coloured film of the MEKFR-ox-NVCz copolymer (copolymer 11) was produced in the doped and conductive form. All reactions were performed in dichloromethane containing 0.1 M B_U4NClO₄. Copolymer 11 films obtained on the surface of the working electrode were removed and washed in acetonitrile and dried at room temperature before characterization. The results were compared with the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2).

The insulating copolymer of NVCz and MEKFR (copolymer 1) was produced by the electroinduced Ce (IV) polymerization method and converted into the conductive form electrochemically on the surface of the Pt electrode (copolymer 11). The polymers were characterized by electrochemical, spectrophotometric and conductivity measurements. The ionization potentials, optical band gap, peak potentials Ep, doping degree and specific capacitance of the copolymer 11 were obtained. The conductivity of the copolymer 11 is lower than the PNVCz and higher than the copolymer obtained by electrochemical oxidation of MEKF-R and NVCz (copolymer 2). The copolymer 11 has a lower onset potential than PNVCz and the copolymer 1 and slightly higher band gap than PNVCz. The capacitive behaviours of the copolymer 11 were very close to PNVCz.

This study focuses on obtaining a green and conductive form of the copolymer of NVCz and MEKFR with the electrochemical method by using a white and insulator form of the same copolymer.

This work provides technical information for the synthesis of conducting copolymer of NVCz and MEKFR.

These copolymers may be in the field of PNVCz applications such as photoconductivity and corrosion inhibition.

Electroinduced Ce (IV) MEKFR redox system was applied for the polymerization of NVCz monomer to produce the copolymer 1. The conductive copolymer 11 was synthesized through electrochemical oxidative coupling of the carbazole groups of the copolymer 1.

The purpose of this paper is to report a novel electrochemical sensor designed to detect the corrosion of metal cans used for beverage packaging.

Electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were performed to detect the corrosion degree of beverage cans that had been stored for 1 month (named s1), 3 months (named s2), 27 months (named s3) and 43 months (named s4).

The EIS results showed that the EIS plot of s1 samples had not developed to a characteristic of two time‐constants, indicating that the coating showed good protective performance. The EIS plots of s2, s3 and s4 showed characteristics of two time‐constants, indicating that the organic coatings of s2, s3, and s4 had lost their protective performance. EN results showed that quantities and amplitudes of transient peaks increased with the increasing storage time, indicating that an increasing degree of local corrosion occurred within the cans. A corrosion process for beverage cans is discussed and can be considered in three stages.

The designed electrochemical sensor was successfully applied to detect the performance of beverage cans and, further, provided scientific proof to evaluate the shelf life of metal cans for packaging.

This paper aims to investigate the galvanic corrosion of titanium/L 316 stainless steel, by electrochemical noise (EN), electrochemical impedance spectroscopy (EIS), and anode/cathode area ratio effect on the galvanic behavior of the couple.

The EN measurement was employed to examine effects of anode to cathode area ratio on the galvanic corrosion behavior between stainless steel L 316 and titanium in artificial seawater. Current noise and potential noise were monitored simultaneously using a three‐electrode configuration under open‐circuit condition. The noise resistance was evaluated as the ratio of the standard deviation of the potential to that of the current noise after removing the DC component. The time‐series noise patterns were transformed into frequency domain by fast Fourier transformation and then their power spectrum densities (PSDs) at specified frequency were determined and compared with the EIS and polarization results.

The EN, EIS and polarization results were in agreement. Galvanic corrosion density increase and galvanic potential moved slowly to negative direction with decrease in anode/cathode area ratio. The results showed that the slope of PSD of the current (i.e the “roll off”) was rising slowly where the anode/cathode area ratio was declined. The relationship between polarization resistance (Rp) and noise resistance (Rn) was investigated. Rt was determined by EIS for samples, and its value compared with Rp and Rn. The result indicates that galvanic corrosion has an inversely relation with anode/cathode area ratio that exposed to aggressive environment.

This paper presents the application of noise analysis to demonstrate galvanic corrosion and the effect of area ratio anode/cathode on current density and galvanic potential.

In this study, corrosion behavior of X53CrMnNiN219 austenitic stainless steel (SS) and X45CrSi93 martensitic SS, as well as the galvanic corrosion produced by coupling of these dissimilar alloys, are evaluated in a 3.5 Wt.% NaCl solution at temperature 25°C ± 1°C.

The corrosion parameters were estimated through a series of electrochemical tests, including Tafel polarization, electrochemical impedance spectroscopy (EIS), and zero-resistance ammeter (ZRA) technique.

The results of polarization measurements indicate that the value of corrosion current in the galvanic pair is slightly higher than that of both the austenitic and martensitic SS during the initial time of immersion in the chloride solution, which is an indication of compatibility of members in the couple. The galvanic current density measured by ZRA technique shows negative values throughout the test; accordingly, the martensitic SS acts as anode of the pair and corrodes preferentially. Localization index values are limited to the mixed corrosion process, showing relative susceptibility of the martensitic alloy to the uniform and localized corrosion (pitting) due to chloride ions.

The originality is the evaluation of galvanic corrosion susceptibility of X53CrMnNiN219 and X45CrSi93 SSs in chloride solution by the various electrochemical methods consisting of Tafel polarization, EIS, and (ZRA) technique. To our knowledge, no work has been reported on this issue for these chemical compositions under this condition up to now.

This paper aims to further investigate the behavior and mechanism in simulated oilfield solution on CO₂ corrosion of P110 steel at various temperatures by potentiodynamic sweep and electrochemical impedance spectroscopy (EIS) measurements, especially discussing the influence of the coverage fraction of corrosion film.

Potentiodynamic sweep and EIS measurements were applied to investigate the behavior and mechanism with the effect of temperature on CO₂ corrosion of P110 steel in simulated oilfield solution at 30°C, 60°C and 90°C.

The corrosion parameters of polarization curves, such as corrosion potential (Ecorr), corrosion current density (icorr), anodic and cathodic branches slopes (βa and βc), were analyzed and discussed in detail. In addition, the equivalent circuit models and ZsimpWin software were utilized to fit and analyze the Nyquist plots. The plots showed that corrosion potential shifted more negatively as temperature increased. The corrosion current density (icorr) initially increased and then decreased with the increase of temperature. The impedance spectra measured at various temperatures had different time constants.

The paper highlights that the coverage fraction θ of corrosion film is one most important and key variable influencing CO₂ corrosion mechanisms.

In this work, a kind of Mannich base (C₂₁H₂₅NO) was synthesized with cinnamal aldehyde, acetophenone and diethylamine in a condensing reflux device based on the conventional method. Optimization of the inhibitor concentration was explored.

Spectral properties of this compound was investigated by FTIR, and its inhibition efficiency and mechanism on N80 steel in 20% hydrochloric acid solution were studied by weight loss measurement, electrochemical measurement (potentiodynamic polarization and electrochemical impedance spectroscopy) and surface analytical measurement (scanning electron microscope with energy dispersive spectrometer).

The results showed that the new inhibitor reduced the double-layer capacitance and increased the charge transfer resistance. The inhibition efficiency is 99.7% when the concentration of C21H25NO is 3%. The adsorption of C₂₁H₂₅NO on N80 steel surface in 20% HCl solution was found to be spontaneous and steady. Observed from the steel surface, an inhibition film was confirmed to be presented after adding inhibitor and successfully hindered the corrosive ions from reaching the bulk steel.

A new Mannich base (C₂₁H₂₅NO) was synthesized by cinnamal aldehyde, acetophenone and diethylamine for the corrosion prevention of N80 steel in 20% hydrochloric acid solution.

The purpose of this paper is to investigate the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using the electrochemical noise (EN) analysis and electrochemical impedance spectroscopy (EIS) techniques.

EN and EIS measurements were employed to study the corrosion behavior of aluminum alloy in Na₂SO₄(0.50 M)/NaCl(0.20 M) solution in presence of inorganic inhibitors. The time‐series noise patterns were transformed into the frequency domain using fast Fourier transformation, and then their power spectrum densities (PSDs) at specified frequencies were determined and compared with the EIS and polarization results.

The EN, EIS and polarization results were in agreement. The inhibitive effect of the anions decreased in the order: CrO₄²⁻>Cr₂O₇²⁻>NO₃⁻>WO₄²⁻>MoO₄²⁻>NO₂⁻. The results showed that the slope of PSD of the current (i.e. the “roll off”) was less where inhibition efficiency was greater. The spectral noise impedance and the modulus of the impedance recorded using impedance spectroscopy showed good agreement.

This paper provides useful information relative to corrosion inhibition efficiency of the sodium and potassium salts using EN analysis technique.

The purpose of this paper was to investigate the anti-corrosion behavior of polypyrrole (PPy) films in different states and presence of alumina nanoparticles synthesized by galvanostatic electropolymerization on stainless steel (SS) electrodes in an artificial seawater solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).

The electrochemical measurements were used to examine the effects of PPy and its nanocomposite on the corrosion behavior of SS type 316L in artificial seawater. A standard electrochemical cell with three electrodes was used for the measurements. The electrochemical response of the coated electrodes in the doped and the undoped state was compared with that of a bare electrode. Corrosion rate information was obtained by the Tafel extrapolation method, where the intersection point of a cathodic and an anodic polarization curve provides both the corrosion potential and the corrosion current. EIS measurements confirmed the potentiodynamic and open circuit potential (OCP) results. The microstructure of the obtained films was investigated by scanning electron microscopy.

The results showed that the coated polymer films shifted the electrode potential toward more positive potentials, but this shift did not lead to passivation. However, a notable synergy was observed between PPy undoped film, oxygen reduction and iron dissolution. The potential of the SS remained in the active dissolution region, and it was not possible to produce a passive oxide layer in this region. PPy separates the metal dissolution process from the oxygen reduction process. This would prevent the local pH increase at the metal surface and subsequent delamination. The polarization curves, EOCP and impedance measurements showed that PPy undoped/Al₂O₃ layers show promise as good candidates for the corrosion protection of reactive metals.

This paper presents that electrodes coated with undoped PPy synthesized in the presence of dodecyl sulfate anions and Al₂O₃ nanoparticles offered a noticeable enhancement of protection against corrosion processes.

Plasma electrolytic saturation (PES) treatments were applied on the surface of AISI H13 steel and corrosion resistance of the treated samples was investigated using electrochemical test methods. The aim was to obtain optimal corrosion resistance of the differently treated samples.

Nitrocarburized and boride layers were produced on AISI H13 steel by the means of the PES technique. Different experimental parameters during each treatment provided different microstructural and electrochemical properties. The techniques used in the present investigation included X‐ray diffraction, SEM, potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS).

The plasma electrolytic nitrocarburising coating was characterized by lower integrity than a PEB coating. All PES coated steels had a noble electrochemical behavior compared to the untreated steel. Different nano‐structures and morphologies obtained by different experimental parameters produced different electrochemical behaviors.

The results obtained in this research into PES techniques can be used wherever good corrosion resistance with the highest efficiency is required.

The speed of treatment by plasma electrolytic saturation techniques makes this method very suitable for industrial production of components.