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Cyanide determination by an ISFET-based peroxidase biosensor

1998; Elsevier BV; Volume: 13; Issue: 9 Linguagem: Inglês

10.1016/s0956-5663(98)00004-9

1873-4235

Viatcheslav Volotovsky, Nack J. Kim,

Electrochemical Analysis and Applications

Horseradish peroxidase immobilized on the surface of an Ion Sensitive Field Effect Transistor (ISFET) can be used for the determination of cyanide ions in aquatic media. When the enzyme is immobilized in BSA gel, the resulting sensor can determine 10−5–10−3 M cyanide. Enzyme immobilization into a positively charged polymer, poly(4-vinylpyridine-co-styrene) (PVPy), seems to cause an increase in cyanide inhibition effects because of anion accumulation in the polymeric matrix, and the resulting sensor can measure cyanide concentration in the range 10−7–10−5 M. Fifty percent peroxidase inactivation was observed with 80 μM KCN in the case of BSA-entrapped enzyme, and with only 0.6 μM KCN when the enzyme was covered by PVPy film. Because of the reversible nature of peroxidase inhibition with cyanide ions, restoration of the enzyme activity after inhibition can be obtained by sensor rewashing in fresh buffer.