Preparation method of modified electrodes and use of modified electrodes in determination of free copper ions in feed additive copper lysine

The invention discloses a preparation method of modified electrodes and a use of the modified electrodes in determination of free copper ions in a feed additive copper lysine. The preparation method comprises 1, carrying out surface treatment on bare glassy carbon electrodes, 2, putting the electrode, counter electrode and reference electrode obtained by the step 1 into a sulfuric acid solution and carrying out round scanning until a voltammogram is stable so that electrode activation is realized, and 3, putting the three electrodes into a solution containing cysteamine chelated metal, and carrying out round scanning to obtain finished modified electrodes. The invention also discloses a use of the modified electrodes in detection of copper ion and copper lysine chelating rates. The preparation method is simple. The modified electrodes are used for detection of copper ion and copper lysine chelating rates and have high accuracy. The detection method is simple and is free of an expensive apparatus.