Electrocatalytic Sensor Research Articles

Electrocatalytic Sensor for the Determination of Chemical Oxygen Demand Using a Lead Dioxide Modified Electrode

AbstractAn amperometric method that makes use of a nano‐PbO2 modified electrode as an electrocatalytic sensor for the determination of chemical oxygen demand (COD) is described. The sensor signal was observed as a result of the detection of the oxidation current due to electrocatalytic oxidation of organic compounds in the sample solution. This sensor responded linearly to the CODCr of standard samples in the range of 5–3 000 ppm and the detection limit was 2.5 ppm. When using the sensor to determine real samples, it displays short analysis time, simplicity and no sample pretreatment. The sensor was stable for over 20 days in real wastewater samples and has successfully been applied to the determination of COD in real wastewater samples.

Electrocatalytic determination of L-ascorbic acid by modified glassy carbon with Ni(Me2(CH3CO)2[14]tetraenoN4) complex.

A novel modified glassy carbon electrode containing Ni(Me2(CH3CO)2[14]tetraenoN4) complex was used as an electrocatalytic sensor for the determination of L-ascorbic acid in pH = 6.6. The peak potential shifted to negative by 205 mV compared with that for a bare electrode in cyclic voltammograms. The calibration curve was linear up to 6.2 x 10(-3) M with a detection limit 3.1 x 10(-7) M and an RSD% better than 2.47%. This newly modified electrode was applied to commercial pharmaceutical tablets, injections and foods. The obtained results were identical to those obtained by the classical 2,6-dichlorophenolindophenol method.

Recent advances in the electrochemistry of porphyrins and phthalocyanines

Recent developments in the electrochemistry of metalloporphyrins and metallophthalocyanines are reviewed briefly by focusing on the electroanalytical, electrocatalytic and electrochemical sensor applications.

New sensor for dissolved dioxygen: a gold electrode modified with a condensation polymer film of β-cyclodextrin hosting cobalt tetraphenylporphyrin

A gold electrode, coated with a thin polymer film of a supramolecular complex of β-cyclodextrin and cobalt tetraphenylporphyrin, is used as an electrocatalytic sensor for determination of dioxygen dissolved in water.

Cyclic voltammetry applied to an oxygen-ion-conducting solid electrolyte as an active electrocatalytic gas sensor

Cyclic voltammetry was applied to a thick-film electrochemical cell having an oxygen-ion-conducting solid electrolyte. Features of the voltammograms appear to depend uniquely on the type of gas exposed to the cell surface. Temperature dependence was studied.

Electrocatalytic glucose sensor

An electrocatalytic glucose sensor for in vivo application has been developed. The sensor is a flow-through cell with three electrodes and can be integrated into a blood vessel. The principle of measurement is based on the direct electrochemical oxidation of glucose at a membrane-covered noble-metal electrode. To test the potential long-term in vivo function of the sensor, it was implanted in the carotid artery of a sheep. Thus, the sensor performance was verified over a period of 71 days. During this time, a nearly constant blood flow through the cell was achieved, which indicates good blood compatibility of the materials used. It was possible to set up a calibration that was valid over 24 days (mean error 2.3 mmol l-1). The tested cross-sensitivity of the sensor towards cysteine, acetyl salicylic acid and other small molecules shows tolerable effects on this type of glucose measurement. Only high concentrations of lactate and ethanol require a special adaptation of the calibration to suppress their influence. Minor cross-sensitivity and promising long-term stability recommend this type of sensor for in vivo monitoring of blood sugar level. However, for intravasal application, it is necessary to modify the present sensor design to a catheter-type construction.

Electrocatalytic Glucose Sensor for Long-Term in vivo use

A catheter shaped electrocatalytic glucose sensor for in vivo application has been developed to determine the glucose level in blood and control the insulin dosage in a closed loop system for diabetes therapy. The principle of measurement is based on the electrochemical oxidation of glucose at a membrane-covered platium electrode. For various potential steps, the impedance obtained at two different frequencies is a function of the glucose concentration. A series of implantations in the vena cava of sheep demonstrated the potential feasibility of the sensor. It was possible to determine the glucose concentration in sheep for more than 130 days with tolerable deviations from glucose reference measurements. The mean error was 2.5 mmol/l. The catheter was explanted after 211 days and histological examination revealed a good biocompatibility of all materials used.

Development and evaluation of an electrocatalytic glucose sensor for diabetes therapy

For the continuous measurement of glucose levels in vivo, an electrocatalytic glucose sensor has been developed. Electrochemical determination of the glucose concentration is effected by measurement of the impedance, which at given potentials is directly dependent on the glucose concentration in the solution. For evaluation and determination of long-term stability, the sensor was first implanted in the carotid artery in the form of a flow-through cell, and was later inserted into the vena cava of a sheep in the form of a catheter. Sensor response was checked periodically by performing glucose tolerance tests. During the implantation period, we also tested the sensitivity of the sensor towards various blood components and medicaments. By adapting sensor calibration, it proved possible to suppress these cross-sensitivity effects. The flow-through cell type of sensor remained functional for up to 71 days post-implantation. So far, data for the catheter-type sensor cover an indwelling time of up to 30 days.

Influence of Paracetamol, Sulfanilamide and Ascorbic Acid on the Electrocatalytic Glucose Sensor

An electrocatalytic glucose sensor for in vivo application has been developed. The principle of measurement is based on the direct electrochemical oxidation of glucose at a platinum electrode without an enzymatic reaction. In an in vivo experiment with sheep the glucose sensor was tested with respect to its cross-sensitivity towards ascorbic acid, paracetamol and sulfanilamide. The influence of these substances could be reduced by an adapted calibration to such an extent, that the sensor performance could be ensured.

New technologies in infrared hydrocarbon detection

For the last three decades electrocatalytic sensor technology has served as the “standard in the industry” for the detection of potentially combustible levels of hydrocarbon gases. While other technologies have existed for years that have offered alternatives to the electrocatalytic hydrocarbon sensor, electrocatalytic technology has held fast as the technology of choice as these alternative technologies either proved unreliable or prohibitively expensive to produce as a field-mounted sensing device. Recent advances in the field of infrared technology have resulted in the development of practical infrared hydrocarbon detectors that allow for significantly improved reliability, area coverage, and drastically reduced maintenance requirements of refineries, petrochemical plants, and gas processing plants, among others. The history, current situation, and possible future of infrared gas detection are reviewed.

Glucose measurements by electrocatalytic sensor in the extracorporeal blood circulation of a sheep

Glucose tolerance tests are monitored by means of an electrocatalytic glucose sensor in an animal experiment in extracorporeal circulation. The sensor is integrated via a vascular graft into an artery of the animal and is operated by the load program of an electronic device. The measurement principle of the electrocatalytic glucose sensor is based on the measurement of the electrode impedance at various potentials. Using the sensor, it is possible to carry out one continuous glucose determination on each day over a week. A calibration applicable to the entire measurement period is found by subsequent correlation of the measured values with the enzymatically determined glucose concentration. In this experiment the measuring error of the sensor is on average 20%.

Development and present status of an electrocatalytic glucose sensor.

For the determination of glucose in body fluids the electrocatalytic sensor seems to be quite favorable, particularly for long-term intracorporeal operation. The measuring response is disturbed by the fluctuating concentrations of interfering substances that are present in body fluids. However, the disturbance can be for the most part controlled, as shown in the case of amino acids. Their marked influence on glucose oxidation is suppressed at a membrane-covered sensor electrode by using a potential step method.