Spectrophotometric Biosensor for Cyanide Determination based on Enzyme Inhibition

Considering the various application of cyanide compounds in different industries, cyanide detection is important for controlling and monitoring of cyanide to prevent the contamination of human life. In present work, an optical inhibition biosensor has been developed for cyanide determination. To achieve this goal, horseradish peroxidase enzyme was immobilized on sodium alginate. The effective parameters on the performance of inhibition optical biosensor including pH of solution buffer, enzyme activity and concentration of substrates (H2O2 and pyrogallol) were optimized. The cyanide determination was based on absorbance reduction of the orange compound, pupurogallin produced from pyrogallol and hydrogen peroxide as substrates, due to inhibitory effect of cyanide on horseradish peroxidase activity. The absorbance of purpurgallin measurements was detected at 480 nm by a spectrophotometer. The cyanide determination was conducted in the range of 1 to 15μM cyanide concentration with a detection limit of 4μM. The high accuracy of the proposed biosensor for cyanide determination in real samples is other reason for possible applicability for cyanide detection