Enzyme biosensors for urea determination based on an ionophore free pH membrane electrode

New Urea Biosensor Based on Urease Enzyme Obtained from Helycobacter pylori

“…The optimum pH of other both urea biosensors prepared with carboxylated PVC membrane and PVC containing palmitic acid membrane were determined as pH 7.2. These results are agreement with the results reported in the literature [3,4,19,23,29,34]. At pH less than 7.2, urease can be denaturated and hence reduce enzyme activity.…”

“…This response time changed between 1 and 2 min. These results were shorter than the results obtained for many urea biosensors [4,23,34]. In conclusion, the response time of the biosensors which we prepared is better than most similar biosensors reported in the literature.…”

“…Until now, carboxylated PVC and PVC matrix containing palmitic acid has been used as a membrane matrix for construction of urea biosensors based on ammonium electrode, and urease has been chemically immobilized on this membrane surface [3,23,[31][32][33]. The results of some other urea biosensors reported in literature were presented in Table 3.…”

“…The linear ranges of the urea biosensors were found to be to 7.10 −2 -3.10 −4 M by [23], 10 −3 -10 −5 M by [34], and 2.1×10 −2 -7.2×10 −5 M by [4]. It can be concluded that the biosensors prepared with urease enzymes obtained from H. pylori are as advantages as that of prepared with Jack bean by using PVC and carboxilated PVC matrix materials for urea determination.…”

“…Enzymatic sensors for the potentiometric determination of urea belong to the best known class of biosensors. In these biosensors a substrate-active enzyme layer is placed directly on the surface of a classical sensor which measures the concentration of products formed in the course of an enzymatic reaction [4,[21][22][23][24].…”