Amino acids using enzymatic biosensors

As a rule, the combined immobilization of oxidase and peroxidase on the electrode allows the determination of metabolite (S) concentration, even if negligibly small. This type of biosensor is the main one used for detection of any particular compound in blood or other multicomponent system glucose, ethanol, cholesterol, proteins, amino acids, etc. For example, for patients with diabetes a rapid analysis of their blood for glucose concentration is a vitally important procedure. We will not attempt to discuss in full all the existing types of biosensor we will just note that enzymatic and cell biosensors are the most widespread types of these appliances. Enzymatic biosensors are more appropriate to the subject of the current monograph and, therefore, they will be discussed below. 

Many potentiometric en2yme electrodes for widely different analyte species can be prepared merely by choosing the appropriate ISE transducer and immobilized enzymatic reagent. Table 5 summarizes the enzymes and ISEs/gas sensors used to construct biosensors for a number of important biomolecules, ranging from urea and creatinine to amino acids, nucleotides, and even glucose and penicillin. In the... 

Plants are useful sources of enzymatic material for analytical chemistry. Using the appropriate transducer, very stable biosensors can be produced because the enzymes remain in their natural environment. Similarly, animal tissue can be considered as a useful bioreceptor for the selective detection of L-amino acids without any notable interference from D-amino acids. Sensor selectivity can also be improved by incorporation of an antimicrobial agent to avoid bacterial contamination. For example, it is recommended that 0.02 % sodium azide is used in the glutamine electrode [17]. 

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