Electrochemical Determination of Dapoxetine HCI in Biological Fluids Using Coated Wire Electrode

Coated wire sensor for potentiometric determination ofDAP （dapoxetine HCI） in pure form and in biological fluidsbased on DAP-TPB （dapoxetine-tetraphenyl borate） as the sensing element in the presence of DOP （dioctylphthalate） as the plasticizing solvent mediator was prepared. The best performance was obtained with a membrane composition of 10.0% （w/w） ion-pair, 45.0% DOP （w/w） and 45.0% PVC （w/w）. The electrode showed a Nemstian response （with a slope of 58.70 mV decade-1） for the concentration range of 4.2 × 10-5-1.0 ×10-2 mol/L. It illustrates a relatively fast response time in the whole concentration range （-15 s） in a pH range of 3.0-7.5. The selectivity coefficients were determined in relation to several inorganic and organic species. DAP is determined successfully in pure solutions and in biological fuids using the standard additions and petentiometric titrations methods.

Development of Chloride Electrode Coated Wire and Composite Systems for Determination Chloride Ion in Gunungkidul Spring Water

The purpose of this research was to fmd out effectiveness of chloride solid membrane electrode of coated wire system compared to solid membrane electrode of composite system, the Nernstian response and character＇s potential response （detection limit, selectivity and response time）. The chloride ISEs （ion selective electrodes） in this research were the solid membrane chloride ISEs based AgC1. There were two types of chloride ISEs that were developed, namely the chloride ISEs of coated wire and composite systems. Both types of electrodes were characterized. The selectivity was done by comparing Esel of the chloride standard solutions and Esel of the interference ions （Br- and I-）. The measurement of chloride ions in water samples was done by using the coated wire chloride ISE, the composite chloride ISE and the Mohr method. We compared the result of the two chloride ISE methods to that of standard method for chloride determination （Mohr） by using F-test and Post Hoc Test LSD （least significant difference） and Duncan. Analysis by using F-test and Post Hoc Test （LSD and Duncan） and characterization results of both the methods showed that coated wire chloride ISE was more effective compared to composite chloride ISE. Nemstian response was 59.83 mV/decade, linier range measurement was 10-1-10-5 M, limit detection was 1.23 × 10-5 M, response time along was 25 s and interfering ion was 10-4 M Br-.

Machine-vision-based electrode wear analysis for closed loop wire EDM process control

The purpose of this study was to develop a closed-loop machine vision system for wire electrical discharge machining(EDM)process control.Excessive wire wear leading to wire breakage is the primary cause of wire EDM process failures.Such process interruptions are undesirable because they affect cost efficiency,surface quality,and process sustainability.The developed system monitors wire wear using an image-processing algorithm and suggests parametric changes according to the severity of the wire wear.Microscopic images of the wire electrode coming out from the machining zone are fed to the system as raw images.In the proposed method,the images are preprocessed and enhanced to obtain a binary image that is used to compute the wire wear ratio(WWR).The input parameters that are adjusted to recover from the unstable conditions that cause excessive wire wear are pulse off time,servo voltage,and wire feed rate.The algorithm successfully predicted wire breakage events.In addition,the alternative parametric settings proposed by the control algorithm were successful in reducing the wire wear to safe limits,thereby preventing wire breakage interruptions.

The Study of the Varying Characteristics of Cathodic Regions for Defective Coating in 3.5% Sodium Chloride Solution by EIS and WBE

The current distributions over carbon steel under iron red alkyd primer exposed to 3.5% sodium chloride solution were mapped using the wire beam electrode （WBE）. The electrochemical impedance spectroscopy （EIS） of the WBE was carded out to analyze the performance of coating delamination and corrosion behavior of carbon steel beneath defective coating. The EIS data revealed that protective capability of coating decreased with immersion time and the degree of cathodic delamination showed a rapid rise. The current density distribution of WBE indicated that cathodic sites was located at the defect at the beginning of immersion and gradually spread into the intact coating. The cathodic regions were distinguished from the anodic area and distributed over the WBE. The changes of cathodic sites could reflect the deterioration process of defective coating. The cathodic area ratio was a more useful parameter than the cathodic delamination degree to evaluate the coating cathodic delamination. The polarity reversals of electrodes at the defect and beneath coating were observed. A simple discussion of relationship between the blister and the polarity reversal was made from a standpoint of electrochemical distribution. WBE method was able to map and record the changes of local cathodic sites beneath defective coating in real time, which could provide more detailed information about the local degradation of coating.

Development of new potentiometric sensors for the determination of proguanil hydrochloride in serum and urine

Potentiometric electrodes were developed for the rapid determination of proguanil hydrochloride in pure samples, pharmaceutical preparations and spiked serum and urine samples using PVC membrane,screen printed（SPE）, coated wired（CWE）, carbon paste（CPE） and modified carbon paste（MCPE）electrodes based on the ion-exchanger of proguanil with phosphotungestic acid（Pr-PT） as a chemical modifier. The prepared electrodes showed Nernestian slopes of 59.7, 58.1, 58.5, 58.5 and 57.0 for the PVC,SPE, CWE, CPE and MCPE for the proguanil ions in a wide concentration range of 1.0 ＊ 10^-5–1.0 ＊ 10^-2mol L^-1 at 25°C with detection limits of 7.94 ＊ 10^-6, 1.0 ＊ 10^-5, 1.0 ＊ 10^-6, 7.07 ＊ 10^-6 and 2.5 ＊ 10^-6 mol L^-1, respectively. The prepared electrodes exhibited high proguanil selectivity in relation to several inorganic ions and sugars and they could be successfully utilized for its determination in pure solutions, pharmaceutical preparations and serum and urine samples using the direct potentiometry and standard addition methods with very good recovery values.

On the localised corrosion of carbon steel induced by the in-situ local damage of porous corrosion products

The effect of in-situ local damage of uniform porous corrosion products on the localised corrosion of carbon steel is investigated using the wire beam electrode technique(WBE)combined with morphology characterisation and electrochemical tests.The WBE measurements demonstrate that the localised corrosion is enhanced by the in-situ local removal of porous corrosion products,supported by the morphology characterisation and electrochemical tests.The enhanced localised corrosion does not originate from the damaged wire in WBE where the corrosion products are removed but from the other undamaged wires,which is reported for the first time.A mechanism is proposed that the intensive anodic polarisation effect of the damaged wire on the undamaged wires could account for the enhanced localised corrosion,which is due to the protective corrosion products newly formed on the damaged surface and the increase in the potential of damaged wire.