▎ 摘　　要

NOVELTY - Detecting L-cystein concentration involves taking 0.5 mu m aluminum oxide powder and 2 mm glassy carbon electrode, adding ultra-purified water, ethanol and distilled water, ultrasonic treating for 3 minutes, drying, dissolving 1 mg analytically pure graphene oxide in 1 mL N,N-dimethyl ammonium formate, ultrasonic vibrating, applying on carbon electrode surface, drying, dispensing 0.002 mol/L 4-formyl benzoate ester-Schiff base nickel complex an N,N-dimethylformamide/ammonium hydroxide solution on electrode surface, absorbing, drying for 1 hour, and washing with distilled water. USE - Method for detecting L-cystein concentration (claimed). ADVANTAGE - The method is simple, safe and environment-friendly. DETAILED DESCRIPTION - Detecting L-cystein concentration comprises taking 0.5 mu m aluminum oxide powder and 2 mm glassy carbon electrode, adding ultra-purified water, ethanol and distilled water, ultrasonic treating for 3 minutes, drying, dissolving 1 mg analytically pure graphene oxide in 1 mL N,N-dimethyl ammonium formate, ultrasonic vibrating, applying on carbon electrode surface, drying, dispensing 0.002 mol/L 4-formyl benzoate ester-Schiff base nickel complex an N,N-dimethylformamide/ammonium hydroxide solution on electrode surface, absorbing, drying for 1 hour, washing with distilled water, removing unadsorbed material, soaking prepared electrode, silver/silver chloride electrode and platinum electrode in saturated sodium chloride solution, adding to L-cystein at different concentrations, adding phosphate-buffered saline, scanning, recording oxidation peak current, performing linear regression, and measuring L-cystein concentration. Concentration (x) and oxidation (y) peak are related by mathematical equation y=-4.53963x 10-5+1.71341x 10-4x.