Zh. Liu et al., DETERMINATION OF ORGANONITRILES USING ENZYME-BASED SELECTIVITY MECHANISMS .1. AN AMMONIA GAS-SENSING ELECTRODE-BASED SENSOR FOR BENZONITRILE, Analytical chemistry, 65(21), 1993, pp. 3134-3136
Organonitriles are considered an important class of compounds which co
ntribute to environmental pollution. A nitrile sensor was developed to
directly and selectively measure nitrile compounds in water. Rhodococ
cus sp. nitrilase catalyzes the hydrolysis of ben zonitrile derivative
s directly into the corresponding carboxylic acid and ammonia. The enz
yme was purified and physically entrapped onto the tip of an ammonia g
as sensing electrode using cellulose dialysis membranes. The resulting
nitrile sensor was relatively stable for up to 4 days at 4-degrees-C,
after daily use at room temperature. It can be reliably used in the p
H range of 6-9. The sensor is demonstrated for the detection of benzon
itrile in neat water samples at concentration levels as low as 1 X 10(
-5) M.