Choline oxidase immobilized into conductive poly(3,4-ethylenedioxythiophene) film for choline detection

The effect of choline oxidase (Chox) on the electrochemical polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) was described. Result shows that the growth rate of PEDOT film varied with the addition of Chox quantity. The properties of PEDOT and PEDOT/Chox films were characterized by XPS and UV–vis absorption techniques. Meanwhile, a novel UV–vis absorbance method for the detection of choline was achieved. In a medium of 1/30 M phosphate buffer solution (pH 8.0), a very sensitive absorbance peak at 293 nm was observed. The linear relationship between UV–vis absorption intensity and choline concentration in a range from 1.0 × 10−6 to 5.1 × 10−5 M was obtained. This method has also been applied to determine choline in several feedstuff additive samples.