Design of a new sensor, based on enzyme tyrosinase, suitable for phenol determination in water was described. The influence of measuring parameters such as pH of the sample and enzyme concentration on analytical performance of the sensor was evaluated. Calibration curves were constructed for catechol, 4-methylcatechol, 4-tertbutylcatechol, phenol, 4-chlorophenol, 2-tertbutylphenol and cresols (p and m isomers of cresol were treated separately) and sensitivity as well as LOD and LOQ were estimated for these phenols. Additionally, the influence of sample matrix components on the electrode response was studied according to the Plackett-Burman experimental design. The following potential interferents which are usually met in waters were taken into account in the examination: Mg2+, Ca2+, HCO3-, SO42-, Cl- as well as Cu2+. It was found that among tested ions only Cu2+ directly affected the electrode response. Determination of phenol index in tap water samples together with recovery studies was also performed. Obtained results suggest that developed sensor can be successfully used for the determination of phenols in concentration range covering its environmental levels. (C) 2009 Elsevier Ltd. All rights reserved