A sensitive amperometric screen-printed enzyme electrode suitable for detection of organophosphate pesticide residue was developed, which can be operated at a low applied potential of 0.10 V. The first part of the study was focused on selected condition such as accession of the modified material and applied potential on electrode, optimization of the pretreatment time and response time, influence of environment temperature and pH of phosphate buffer solution, effect of substrate concentration, choice of immobilization method, effect of temperature and time when enzyme was immobilized on screen-printed electrodes. In the second part of the study, pesticide paraoxon-ethyl and reality sample were detected. The lowest detectable concentration in a standard solution was 2.10 ng•mL^－1. The immobilization procedure can be easily adapted to the working electrode employed by electrochemical detectors. This novel method of screen-printed enzyme electrode is promising for the development of subminiature apparatus for measuring pesticide residues.

Key words: enzyme electrode, screen-printed, organophosphate pesticide residue, electrochemistry, acetylcholinesterase