Development of a biosensor for gaseous cyanide in solution

A gas-phase biosensor was developed using cyanide degrading bacteria, an oxygen electrode and a gas permeable PTFE membrane; Cyanide degrading bacteria, Pseudomonas fluorescens NCIMB 11764, consume oxygen upon degradation of cyanide. A change in oxygen concentration was detected using a Clark oxygen electrode. A linear relationship was observed between the current decrease and the cyanide ion concentration in the range 0.1-1 mg/l. The optimum working conditions of the sensor were pH 2 and 30 degrees C. The sensor was unaffected by heavy-metal ions and biochemical oxygen demand (glucose, glutamic acid). A good correlation was found between results obtained with the biosensor and those obtained using the Japanese Industrial Standard (JIS) method. The correlation coefficient was 0.995. When the biosensor was stored at 4 degrees C, but operated at 30 degrees C, the sensor was stable for up to 1 month. (C) 1996 Elsevier Science Limited