INVESTIGATION AND OPTIMIZATION OF REACTIVATION OF UREASE BIOSENSOR FOR HEAVY METALS INHIBITION ANALYSIS

16 At present, one of the most acute environmental problems is the contamination with waste products [1]. Among the various pollutants, heavy metals and their compounds are notable by abundance, high toxicity, ability to accumulate in living organisms [2]. They are widely used in manufacture, therefore, despite the clean-up, the content of heavy metals in industrial wastewater is rather high. They also enter the environment with sewage, smoke and dust from industrial enterprises. Many metals form stable organic compounds, high solubility of which facilitates the migration of heavy metals in natural waters. More than 40 chemical elements are referred to as heavy metals, but significantly fewer number should be controlled taking into account toxicity, persistence, abundance, an ability to accumulate in the environment [3, 4]. In the aquatic environment, microparticles of heavy metals are present as solutions, suspensions and colloids. Free hydrated ions, simple inorganic and organic complexes are soluble [5–9]. Currently, there are many methods, which are widely used for the determination of heavy metals, such as atomic absorption spectrometry, plasma mass spectrometry, etc. However, these methods utilize sophisticated appliances and are unsuitable in the field [10]. Electrochemical biosensor methods in general are more reasonable in the field because they do not require complex equipment [11–13]. Biosensor determination of heavy metal ions is based on their inhibition effect on enzymes. For example, ions of copper, cadmium, mercury, zinc are effective inhibitors of the urease activity in the urea hydrolysis. An important stage in the running of urease biosensor is a procedure of its reactivation after inhibition by heavy metal ions. An exposure of the inhibited biosensor in UDK 543.6 + 577.15 + 543.555 + 544.475 doi: 10.15407/biotech8.06.016