A PROCESS FOR THE DEVELOPMENT OF AN ULTRA-SENSITIVE TEST METHOD FOR DETECTION OF MERCURY ION

摘要

Toxicity of mercury and its compounds is well known and increasing environmental pollution by mercury and its compounds by human activities require rigorous assessments. In the United States, both Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) allow levels of total mercury at less than 0.002 milligram (mg)/Litre in both tap and bottled water. The Bureau of Indian Standards (BIS) has laid down safety limits for drinking water at 0.001 mg of mercury /Litre. But extensive survey of mercury pollution, toxic at low very concentrations, require either ultra-sensitive Mercury Test Method or help of highly sophisticated and costly instruments like atomic absorption spectrometry, atomic emission spectrometry, electron probe microanalysis etc and lead scientific workers. The main objective of the present invention is to develop an ultra sensitive mercury ion test method based on an enzymatic reaction. The reaction involves hydrolysis of soluble starch by a non-specific glucan hydrolase and inhibition of its activity by mercury ion as monitored by starch-iodine color reaction. The color change developed at lowest mercury concentration of one ppb (parts per billion) can be visualized by naked eye. Main Advantages of the Process: The method is very cheap, involves the use of a stable enzyme which is easily available from the plant (Tinospora cordifolia) that grows wild on unconditioned soil. Enzyme, either in crude form, ethanol precipitated form or even in pure form could be used. It does not require any costly or hazardous chemicals and results can be visualized with naked eyes for level of mercury upto 1ppb. Lead and Cadmium do not interfere with the results. The method can be used for preliminary detection of mercury in water above safe range of lppb. The method does not require the involvement of any skilled personnel and a field worker can easily perform the test. The present invention carries ten (10) claims regarding the novelty and uniqueness of the innovation.