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Zhou, X.Y. and Shang, H.J., 2020. Joint development of marine industry and regional economy. In: Al-Tarawneh, O. and Megahed, A. (eds.), Recent Developments of Port, Marine, and Ocean Engineering. Journal of Coastal Research, Special Issue No. 110, pp. 116–119. Coconut Creek (Florida), ISSN 0749-0208.The development of marine economy is closely related to the economic development of surrounding areas. Promoting the development of the economy of the entire area by adjusting the marine industry structure has become an important impetus for promoting the economy of coastal areas. This paper takes the Yangtze River Delta coastal area as the subject and construct a model to study the joint development of the marine industry and the regional economy. The research results show that the marine economy of Yangtze River Delta has developed rapidly and contributed greatly to the development of the economy of the entire area; the tertiary industry takes the highest proportion in the marine industry structure, and it plays the largest role in it; there is a close relationship between the output value of marine industry and the output value of regional economy. Each 1% increase in the output value of the marine industry will lead to a 0.635439% increase in output of regional economy. The research results provide useful reference and guidance for the economic development of other coastal areas in China.

The electrochemical characteristics of poly(o-phenylendiamine) (POPD) film modified electrodes have been investigated using different electrochemical techniques. The main interest is focused on the effect of potential and film thickness on the electrode process. Good agreement has been found for the apparent diffusion coefficient estimated by chronocoulometry and impedance spectroscopy. The charge transfer process within POPD films is diffusion processes at negative and positive overpotentials and electron hopping mechanism at formal potential. The POPD film conductivity of the oxidized state is better than that of the reduced state. For all electrode processes, the H+ may penetrate the film/electrolyte interface and take part in charge transfer or protonation-deprotonation of phenazine rings.

A novel electrophoresis technique, in which the separation column was replaced by a strip of Nafion membrane (5.0 cm x 0.20 mm x 0.25 mm), was developed for the separation of an amino acid mixture (glycine, asparic acid and lysine), followed by quadruple-pulse electrochemical detection. Nafion membrane contains hydrophilic pores (10-20 A and 50-60 A in size) acting as very narrow electrophoresis channels. The fixed-charge sites (-SO(3) (-)) on the hydrophilic pore surface provide a strong charged background. A platinum disk electrode (0.90 mm inner diameter) was employed as the detection electrode and the electrophoresis cathode was used as the quasi-reference and counter electrode for the end-column electrochemical detector, without decoupler. Under optimized conditions the mixture of amino acids could be separated at a voltage of only 90 V with a detection limit of 10(-7) M, indicating that Nafion membrane electrophoresis is a potentially attractive technique for the separation of small organic molecules or ions.

The glutathione (GSH) self-assembled monolayer and its compexlation with Cu2+ were studied by using voltammetry and EQCM. It was found that the monolayer could rearrange during the redox process of Cu2+/Cu+. The protonating, or not, of the carboxyl terminates of the adsorpted GSH molecules influence the compexlation interaction significantly for they are the key binding sites. The GSH monolayer had the capacity to accumulate Cu2+ and the monolayer modified gold electrode was employed to detect the low levels of Cu2+ with a limit of 1.0×10−10 mol L−1.

C60 was covalently attached onto a self-assembly monolayer (SAM) of glutathione (GSH) formed on a Au electrode. Characterization of the resulting monolayer was carried out on a FT-IR spectrometer and its electrochemical properties were investigated with cyclic voltammetry and impedance methods. It was found that the pinholes on the C60-GSH monolayer showed the response of the opening and closing with the change of pH. The modified electrode can be used to determine NADH in neutral solution.

Mixed dodecanethiol-glutathinone self-assembled monolayers (DDT-GSH) were prepared on a gold electrode and further derivatized to form a monolayer of cupric hexacyanoferrate (CuHCF). Electrochemical behavior of the modified electrode was investigated by cyclic voltammetry. This inorganic monolayer modified electrode is electroactive and its surface concentration is 4.2×10–10 mol cm–2. It is observed that this modified electrode shows selectivity to potassium ion and exhibits an ideal Nernstian response with a slope of 60 mV/decade to potassium ions in the range from 10–2 to 1.0 mol L–1.

A monolayer membrane of 2-mercaptobenzothiazole (MBT) was prepared on a gold electrode through a self-assembly procedure. The monolayer structure and the electrochemical properties were investigated by various electrochemical techniques, like cyclic voltammetry and an impedance measurement with external redox. Experiments show that MBT can form a closely packed monolayer that can be charged due to the active N atom. The amount of charge on the membrane surface varies with the solution pH, and the monolayer shows opening and closing which depends on the solution pH. The electrostatic interaction of the monolayer with other ions is also related to the pH in solution. An impedance analysis shows that the heterogeneous electron-transfer rate of a fast redox like Fe(CN) 6 3-/4- decreases from 1.2 x 10 -2 to 4.7 × 10 -5 cm s -1 in neutral solution due to blockage of the self-assembled monolayer membrane.

Monolayer films of thiols with different terminal groups (CH3, COOH and NH2) were prepared on gold electrodes using a self-assembling procedure. Cyclic voltammetry was used to investigate the electron-transfer reaction of potassium ferricyanide at the thiol modified gold electrode in the presence of surfactants. It was found that surfactants show some effects on the electron-transfer reaction at the thiol modified electrode. Cationic surfactants can improve the reversibility of a redox reaction at the thiol modified gold electrodes, while anionic surfactants cause a little inhibition of electron transfer of the redox at both methyl and carboxyl terminal thiol modified gold electrodes. Surfactants can interact with thiol monolayers in different ways, changing the structure and properties of the monolayer film, and can further affect electron transfer at the modified gold electrode.

Cyclic voltammetry and chronoamperometry were used to study the deposition of polypyrrole on a decanethiol self-assembled monolayer modified gold electrode (PPY/SAM/Au). The voltammetric behavior of the PPY/SAM film was investigated in the presence of several different electrolytes. It is found that the SAM shows great influence on the nucleation and growth of the PPY film. The reaction of the SAM and the anions causes the different voltammetric behavior of the polymerization of pyrrole on the modified electrode. Chronoamperometry shows the nucleation and growth of the PPY is initially inhibited but followed by a rapid increase. The SAM also influences electrochemical behavior of PPY film. Experiments show that the SAM can greatly depress the diffusion of anions in the PPY film, and minimize the background capacitance current.

A novel glassy carbon electrode modified with Malachite Green was investigated. The modified electrode can be used to determine dopamine (DA) and ascorbic acid (AA). The anodic peaks for ascorbic acid and dopamine were separated (ΔEpa about 200 mV) at the poly(malachite green) modified electrode. Thus, DA can be determined in the presence of AA.

The electrochemical redox mechanism of I(-) ion under different concentrations on gold electrodes was studied in detail using the EQCM technique (a combination of the QCM technique and cyclic voltammetry). The redox behavior of the I(-) ion on a gold microelectrode when no supporting electrolyte was added was compared with a conventional gold microelectrode. Due to the small current and the very low solution iR drop of the microelectrode, the actual oxidation potential of I(-) on the microelectrode was much more negative than that of the conventional electrode and its anodic peak was better defined. Therefore the gold microelectode was employed for the determination of I(-). A linear range of 1.0x10(-5)-0.1 mol l(-1) with a detection limit of 1.0x10(-6) mol l(-1) was obtained on the microelectrode in pure KI aqueous solution. Two samples were measured using this method and the results were in good agreement with those indicated or calculated..

This paper reports our recent research about poly(neutral red) film modified glass carbon electrodes and their electrocatalytic oxidation reactions for both dopamine and ascorbic acid. The catalytic currents are linearly related to both dopamine and ascorbic acid concentrations in the ranges 5.0×10 −6 –2.0×10 −4 and 2.5×10 −5 –1.0×10 −1 mol l −1 , respectively. Moreover, the dopamine and ascorbic acid concentrations can be determined simultaneously by using the difference of the catalytic currents. This method has been used for determining dopamine and ascorbic acid concentrations in real samples with satisfactory results.

The resistance of the polypyrrole film (PPy) was measured in situ by the dual-disk microelectrode. Some factors (such as the kinds of electrolyte, anionic concentration, oxidation potential and solution pH) which influence the resistance or the stability of the film have been studied in detail. The oxidation potential had the most critical effect on the resistance and the stability of the film.

A conductivity equation based on the dual-disk microelectrode was derived. This electrode was used for in situ measurement of the conductivity of polyaniline. Some factors such as electrochemical potential, solution pH, scan rate and over-oxidation, which influence the conductivity of polyaniline, were conveniently controlled by this electrode. Experimental results proved that this electrode is very useful for measuring the relative conductivity in situ and studying the conducting mechanism of conductive polymers.

Dual-disk microelectrodes with interelectrode gap widths of 5 to 48 μm were used for the measurement of the electron transfer number n app of dioxygen reduction. The effects of the gap width, the scan rate and the diffusion coefficient on the generation-collection properties were studied. An equation for n app was derived and a semi-empirical expression of the collection efficiency was obtained. On the bare platinum electrode, the reduction of dioxygen is dominated by a four-electron reaction. On the polypyrrole (ppy) film containing nanodispersed platinum particles, more H 2 O 2 is produced and its catalytic activity varies with the conductivity of the film. The n app is affected by the pH value. The diffusion coefficient of H 2 O 2 in 1.0 M KOH determined by the dual-disk microelectrode is 1.29 × 10 −5 cm 2 s −1 .

The direct electron transfer reaction of glucose oxidase (GOx) at a bare silver electrode is verified. The electron transfer number n = 2, electron transfer coefficient α = 0.45 and rate constant of the electrochemical reaction Ks = 0.1 s−1 are obtained. This communication presents a multimolecular adsorption model to explain the properties of the direct electron reaction between GOx and bare silver electrodes. The residual valence force may be an important factor to ensure a direct electron transfer reaction on the bare electrode. On the basis of the experimental fact that only biologically active GOx exhibits electrochemical activity in solution, a facile analytical method for analyzing the active GOx concentration is developed. The results determined correspond very well to that of a spectrometric method.

A new type of disposable electrochemical sensor, which consists of a piece of Nafion membrane and a microdisk electrode, is developed. The Nafion membrane, which is butted by the electrode to actualize the electrochemical reaction, acts as the immobilization bed for mediator (anthraquinone) and enzyme (glucose oxidase). The sensor is not vulnerable to being broken or contaminated. By replacing the immobilization beds with different mediators and different enzymes in series, the sensor may be employed for the rapid analysis of a multi-component sample. The sensor exhibits a rapid, stable response to glucose. A consecutive calibration test shows that the original tip has an active period greater than 24 hours and the storage life time longer than 3 weeks. The linear range and the sensitivity of the original sensor are 6 mM and 0.52 nA/mM, respectively.

The electrochemical redox of hemoglobin at a bare silver electrode promoted by cetyl pyridinium chloride with the cyclic voltammetric technique has been studied. The electrode reaction exhibits such good stability that the peak currents change less than 8.5% (oxidation) and 10.2%(reduction) for a continuing scan of 30 min in a solution containing 1 × 10−7mol/L hemoglobin. The electrode reaction rate constant Ks is 0.0865s−1 with a single electron transfer. Moreover, both the oxidation currents and the reduction currents are linear with the concentration of hemoglobin over the range of 1 × 10 −8−5 × 10−7mol/L. So, it can be used as an analytical method of determining hemoglobin.

A series of dual-cylinder microelectrodes with different interelectrode gap were constructed with 7 μm diameter carbon fibers. The collection-efficiency, feedback and shielding properties were studied in dctail with cyclic voltammetry and chronoamperometry for the case of the ferrocyanide(III/II) couple. The effect of the collector potential on the collection-efficiency and the currents at the anode and cathode electrode were discussed. The application of these dual-cylinder microelectrodes to determine the electrochemical reaction mechanism was demonstrated.

Platinum dual-disk microelectrodes with interelectrode gaps of 5–40 μm were constructed for the first time by fixing two 60 μm diameter platinum wires onto a glass slide with epoxy resin as a fixative. The collection efficiency, shielding and feedback factors were investigated in detail. The collection efficiency is related both to the geometry gap width and the method used to polish the electrode and increases with a decrease of the gap width. The collection efficiency for a dual-disk microelectrode with a gap of 5 μm is 44.4%. The collector current decreases with an increase of the concentration of the ascorbic acid added to the solution of 2.0mmoll1 K4Fe(CN)6, because the follow-up chemical reaction between Fe(CN)63 and the ascorbic acid causes a decrease of the concentration of Fe(CN)63 diffusing to the collector. Shielding and feedback factors of this device are very small. The fluctuation of the collector current was observed due to the influence of the natural convection or vibration. The effects of temperature and stirring were also discussed. Results show that both the temperature and stirring result in an increase of the generator current. However, the collector current rises with the temperature and falls rapidly with an increase of the stirring rate.

A pH sensor was constructed with a polyaniline-coated piezoelectric crystal. Its resonant freqency is a function of pH in the range 2–12. It has a good selectivity, a long life and a wide linear resoponse range. In the present work, polyaniline films were electrochemically deposited onto one of the two gold surfaces on the quartz crystal by cyclic voltammetry. Some factors that influence the resonant oscillation frequency have been investigated in detail.

Surface-Enhanced Raman Scattering (SERS) spectra of bilirubin–metal ion (Cu2+, Co2+, Zn2+, Cd2+) complexes (MBR) are reported. These spectra reveal significant differences between MBR and bilirubin (BR) itself. But SERS spectra of bilirubin–Cu2+, Co2+, Zn2+, Cd2+ complexes are similar to each other. The mole ratio of bilirubin-metal in the complexes M2+ : BR = 1 : 1 was measured. Empirical assignments of the major SERS bands are given. The spectrum of CuBR in solution is consistent with a square planar structure. It should be noted, however, that H2O or COOH of another BR molecule occupy the positions above and below the plane in solutions of complexes of this type and forms CuO bond. By comparing the SERS spectra of bilirubin-copper (or zinc) and biliverdin-copper (or zinc) complexes, the similar Raman frequencies and relative intensities were attributed to the oxidation of the bilirubin-copper (or zinc) complex to the green biliverdin-copper (Zn) complexes. It is shown that . © 1995 John Wiley & Sons, Inc.

A novel method has been developed for the fabrication of carbon fiber cone nanometer-size ultramicroelectrodes (nanoelectrodes) with overall tip dimensions as small as 50 nm in diameter. In this method, carbon fibers were initially etched by an argon ion beam thinner. Afterward, a single etched carbon fiber was inserted into a glass capillary, which was then sealed by heating the glass/fiber interface in a vacuum; thus, no epoxy resin is involved. The success rate of our fabrication route for the electrodes with overall tip diameters of up to 500 nm was about 80%; for those with tip diameters of up to 100 nm, it was about 50%. The fabricated carbon fiber cone nanoelectrodes (CFCNEs) were inspected by optical and scanning electron microscopy. Their electrochemical behavior was examined by cyclic and linear sweep voltammetric measurements of ferricyanide and ferrocene ions in aqueous and nonaqueous media. The potential analytical applicability of the CFCNEs was tested by differential pulse voltammetric measurements of two well-known neurotransmitters, dopamine (DA) and 5-hydroxytryptamine (5-HT), and the results achieved were highly satisfactory. The calibration plots obtained were linear over the ranges from 5.0 × 10(-7) to 1.0 × 10(-4) and from 2.0 × 10(-6) to 1.0 × 10(-4) mol/L, with limits of detection of 1.0 × 10(-7) and 5.0 × 10(-7) mol/L for DA and 5-HT, respectively. Some advantages and improvements of the proposed CFCNE fabrication method, especially with respect to smoothness of the fiber (electrode) surface, strength, and control over the fiber tip dimensions, are also discussed.

In hydrogen peroxide-EDTA-sodium phosphate solution (pH 11.0), biliverdin (BV) shows a very sensitive cathodic polarographic wave at about −0.82 V (vs. Saturated Calomel Electrode, SCE). By using derivative single-sweep polarography, the wave height varies linearly with BV concentration over a range of 6 × 10−8 M to 2 × 10−6 M, so it can be used for the determination of BV. Various electrochemical techniques have been used to investigate the characteristics of the wave and the electrode reaction mechanism. As a result, the polarographic wave is identified to be an adsorptive-catalytic wave, and the electrode mechanism is considered to be a catalytic reaction coupled to an irreversible charge transfer process. In the electrochemical process, BV acts as catalyst and hydrogen peroxide as oxidizer. In this article, the rate constant of the catalytic reaction is also determined.

A total mass flux recycling model has been used to develop a theory for parallel dual-cylinder (PDC) microelectrodes held at a small constant potential difference in static solutions containing a reversible redox couple for the case of steady-state response. The bilinear transformation of coordinates in diffusion space has been used in the treatment. In the model used it is assumed that lines of mass flux and equiconcentration surfaces established between a microcylindrical anode and cathode are represented by orthogonal circular functions. It is shown that, using a PDC device with a very small interelectrode gap, data obtained from non-stirred ferri/ferrocyanide solutions are in good agreement with predictions of the established theory.

A polarographic method for the determination of bilirubin is described: In hydroquinone-sodium phosphate buffer (pH 11.2) medium, bilirubin can be rapidly oxidized to a green product, which causes a sensitive polarographic wave at −0.83 V (vs. SCE); the peak current of the wave is linear with the bilirubin concentration over a range of 3×10−7 to 5×10−6 mol/l. It has also been found to be more stable than that produced by bilirubin; in general, it can remain unchanged for about 1 h at room temperature and exposure to air. This overcomes the instability of bilirubin for its direct assay to a certain extent. If a small amount of EDTA is added to the solution, the stability of the wave can be further improved. In addition, the characteristics of the wave have been investigated and it has been confirmed to be an adsorptive catalytic wave. The chemical reaction mechanism is discussed and the green product is confirmed to be biliverdin.

Cyclic voltammetric scan of the glassy carbon substrate in an acidic solution containing both uranyl salt and ferricyanide can result in the new surface-deposition of an inorganic redox active film–polynuclear uranium hexacyanoferrate.

A carbon fibre ultramicroelectrode array modified with Nafion was fabricated and characterized by cyclic voltammetry, chronoamperometry and anodic stripping voltammetry. The array was employed for the measurement of dihydroxyphenylalanine ( l -DOPA) and the mechanism of the electrode reaction was studied. The voltammetric response was evaluated with respect to the pH of the electrolyte, the amount of coated Nafion, accumulation potential, l -DOPA concentration and other variables. The array was compared with a conventional glassy carbon electrode during anodic stripping voltammetry with and without stirring. A 5-min preconcentration period permitted convenient measurements down to 1.0 × 10−7 mol l−1 and the reproducibility of the process studies was satisfactory with a relative standard deviation of 5.5%. No major or minor interferences were observed during analysis in the presence of an excess of various metal ions and cations. Correlation with a spectrophotometric l -DOPA measurement is reported. Satisfactory results were obtained for the measurement of l -DOPA in injection solutions and tablets.

In an acetate acid buffer solution (pH = 4.5) containing 2-(3,5-dibromo-2-pridyl)azo-5-diethylaminophenol or 3,5-2Br-PADAP and nitrite, there is a catalytic single-sweep polarographic peak that is very sensitive and selective to cobalt(II). The linear range is from 1 × 10−10 M to 1 × 10−6 M, with a detection limit of 5 × 10−11 M. Most common cations and anions do not interfere with the determination. The method has been used or the determination of trace cobalt in human hair and pure nickel nitrate samples. The mechanism involved has been investigated by various electrochemical methods, and the catalytic process is .

Cobalt cyanometallate thin film modified electrodes have been prepared and also electrochemically and spectroscopically characterized. Results showed that these films can be considered as novel Prussian Blue analogues. The selective cation transport into or out of these films has been explained in terms of the effective ionic radii and the channel size in the film lattice whereas other factors can not be negligible. On the other hand, the high redox-reversibility and high stability of the modified electrodes make them potentially attractive in application of catalysis and electrochromism.

A sensitive single sweep polarographic peak, related to the nitrite concentration, appears in a slightly acidic solution containing nitrite and thiourea. The peak is ascribed to the reduction of formamidine disulfide (RSSR) resulting from the reaction between nitrite and thiourea. The reduction process involves a slow conversion of this disulfide to mercury sulfide, i.e.a preceding reaction mechanism. The method is used to determine trace concentrations of nitrite, with a detection limit of 5×10-7mol/dm3. The sensitivity increases ten times when catholic stripping voltammetry is used at the static mercury electrode.

Preparation et caracterisation d'un film d'hexacyanoferrate de titane depose sur une electrode de carbone vitreux

Une electrode de carbone vitreux modifiee par un film mince de zeolite (hexacyanoferrate (II), (III) de chrome (III)) est examinee pour ses proprietes d'electrochromisme

Four types of carbon fiber microelctrodes modified with polyaniline (PAn) and platinum particles (Pt) were fabricated to determine H2O2 at + 0.60 V (vs. SCE). The sensitivity, stability and selectivity of different electrodes were compared. The electrode modified with a sandwich film of PAn-Pt-PAn offered the best result. The linear range was 4.0 × 10−7–2.4 × 10−4 M with a detection limit of 1.0 × 10−7 M. The relative standard deviation (RSD) for 10 μM H2O2 was 1.9 % (n =7). The electrode was used to determine the H2O2 in the rainwater.

A piezoelectric crystal immunosensor for the detection of bovine haemoglobin has been developed. The immobilizing process was monitored by determining the frequency shift of a quartz crystal microbalance (QCM). Bovine haemoglobin concentrations in the range of 0.001 to 0.1 mg/ml could be detected by the system. The influence of the liquid depth on the frequency of QCM was discussed. The interference of bovine serum albumin was also studied.