Biomedical subjects

M Boujtita

Publications and source records attributed to M Boujtita.

4 recordsLinked to original sources

PubMed2000

Development of a disposable ethanol biosensor based on a chemically modified screen-printed electrode coated with alcohol oxidase for the analysis of beer.

A disposable amperometric biosensor for the measurement of ethanol has been developed. It comprises a screen-printed carbon electrode doped with 5% cobalt phthalocyanine (CoPC-SPCE), and coated with alcohol oxidase; a permselective membrane on the surface acts as a barrier to interferents. The measurement of ethanol is based on the signal produced by H2O2, the product of the enzymatic reaction. Optimisation studies were performed using amperometry in stirred solution and the magnitude of the signal was found to be dependent on pH, enzyme loading, type of membrane and applied potential. The same technique was used to evaluate the biosensor for the determination of ethanol in samples. The results obtained compared well with the manufacturers specifications. In order to test the possibility of using the devices in the field, chronoamperometry was also used to determine ethanol in the same beer samples. The precision and recovery data again indicated that the biosensor should give reliable results under the conditions described.

Alcohol Oxidoreductases↗

PubMed2000

Ferrocene-Mediated carbon paste electrode modified with D-fructose dehydrogenase for batch mode measurement of D-fructose.

A mediated modified carbon paste and renewable surface electrode for fructose amperometric measurement based on D-fructose dehydrogenase (FDH) was prepared and optimized. Commercially available ferrocene (FcH) and hydroxymethyl ferrocene (FcCH2OH) were used as mediators. The substituted FcH showed better linearity and higher sensitivity. The influence of different experimental parameters was studied for optimum analytical performance. The final FDH-modified electrode showed good analytical performance for batch mode measurements of fructose.

Beverages↗

PubMed1999

Development of renewable surface biosensors to meet industrial needs for measurement of glucose in fruit juices.

Most biosensors reported to date have been prepared, studied and used under laboratory conditions. The feasibility of a very great number of biosensors seems to be demonstrated and their characteristics, very often, established as corresponding to the demands of the modern analysis. The operational stability of the biosensors, according to authors, is almost always acceptable. The long term storage, with analytical quality conservation that is necessary to commercialise products, has rarely been studied. The stability of biosensors has to remain not only during the fabrication step or their subsequent utilisation, but also throughout the whole commercial shelf-life of the sensor, from producer to end user, through wholesaler and/or retailer. We developed the manufacturing processes, on a large scale, of renewable surface electrodes modified with enzymes such as oxidoreductases. The process consisting of several steps is described and the analytical behaviours of resulting biosensors is studied and correlated with the effects of different constraints applied during the fabrication process.

Beverages↗

PubMedDate not supplied

Biosensor for determination of glucose and sucrose in fruit juices by flow injection analysis.

Glucose and sucrose were measured with an amperometric method by using the flow injection analysis technique. A carbon paste electrode with a renewable surface containing glucose oxidase, horseradish peroxidase, and ferrocene was used in combination with the soluble enzymes invertase and mutarotase. The effect of invertase, mutarotase, and ascorbic acid on the electrode response was examined. Glucose and sucrose concentrations were determined with < 3% errors. The proposed method for glucose and sucrose measurements was validated in real samples of fruit juices. The results were also compared with those obtained with the ultraviolet method.

Ascorbic Acid↗