▎ 摘　　要

NOVELTY - Glassy carbon electrode in suede is polished using aluminum oxide powder, and resultant electrode is ultrasonically cleaned for 2-5 minutes. Resultant material is dried using nitrogen to obtain bare glassy carbon electrode. Graphene oxide is electrodeposited on bare glassy carbon electrode by cyclic voltammetry method, to obtain graphene oxide/glassy carbon electrode. 3-5 mu L DNA-silver cyanide solution is added to graphene oxide/glassy carbon electrode, assembling, and obtained electrode is gradually washed using secondary distilled water, to obtain electrochemical biosensor. USE - Manufacture of electrochemical biosensor (claimed) used for detecting terminal deoxynucleotidyl transferase enzyme concentration, and preparing silver nanoclusters. ADVANTAGE - The method efficiently and economically provides electrochemical biosensor which is capable of accurately detecting hydrogen peroxide and terminal deoxynucleotidyl transferase enzyme concentration with high sensitivity and detecting speed. DETAILED DESCRIPTION - Glassy carbon electrode in suede is polished using aluminum oxide powder for 2-5 minutes, and resultant electrode is placed in ultrasonic cleaner with secondary distilled water, and ultrasonically cleaned for 2-5 minutes. The resultant material is then dried using nitrogen to obtain bare glassy carbon electrode. Graphene oxide is electrodeposited on bare glassy carbon electrode by cyclic voltammetry method, to obtain graphene oxide/glassy carbon electrode. 3-5 mu L DNA-silver cyanide solution is added to graphene oxide/glassy carbon electrode, assembling, and obtained electrode is gradually washed using secondary distilled water, to obtain electrochemical biosensor. 5-10 mg Graphene is dissolved in 5-10 mL 0.1-0.3 M acetic acid buffer having pH of 5-6, and ultrasonically dispersed for 2-5 hours, to obtain graphene dispersion. 1-3 mu L Secondary distilled water, 5-10 mu L DNA solution having concentration of 10-15 mu M, 1-2 mu L 2'-deoxycytidine 5'-triphosphate solution having concentration of 10-15 mM, 1-2 mu L reaction buffer and 0.2-0.4 mu L 10-20 U/ mu L terminal deoxynucleotidyl transferase solution are added to PCR tube, oscillated for 2-5 minutes, and mixed uniformly. The resultant mixture is then placed in water bath at 35-38 degrees C for 2-3 hours, and polymerase chain reaction (PCR) tube is placed in 70-80 degrees C water bath for 10-20 minutes to obtain extended DNA reaction solution. DNA is single-stranded DNA containing hydroxyl group. 25-50 mu L 20-40 mM phosphate buffer having pH of 7, 5-10 mu L extended DNA reaction solution, 5-10 mu L silver nitrate solution having concentration of 1-3.0 mM and 10-20 mu L secondary distilled water are added to PCR tube, mixed, heat-preserved for 15-20 minutes, and 5-10 mu L prepared aqueous solution of sodium borohydride having concentration of 1-3 mM is added to the mixed solution. The resultant mixture is continuously oscillated for 1-2 minutes to reduce the silver ions. The PCR tube is wrapped with tin foil, and reaction is carried out at room temperature for 1.5-2.5 hours to obtain silver nanoclusters. An INDEPENDENT CLAIM is included for method for detecting terminal deoxynucleotidyl transferase enzyme concentration using electrochemical biosensor.