Biosensors for the determination of phenol in real matrices such as oi
l press and industrial wastes and sea-, lake and river waters are prop
osed. Optimization of the experimental parameters, especially regardin
g enzyme immobilization, was performed. The biosensors are based on a
Clark oxygen electrode coupled with tyrosinase immobilized by three di
fferent methods. Biosensors were also tested in order to verify whethe
r their direct use with environmental samples and in in situ analysis
is possible.