▎ 摘　　要

NOVELTY - The system has a graphene-modified graphite pencil working electrode comprising a graphite pencil base electrode and a layer of graphene on a surface of the graphite pencil base electrode, where the layer of graphene comprises wrinkled graphene sheets, a counter electrode and a reference electrode. Thickness of the wrinkled graphene sheets corresponds about 1 to 10 layers of graphene. Charge transfer resistance of the graphene-modified graphite pencil working electrode is 95 percentage less than the charge transfer resistance of the electrode as the working electrode. USE - Graphene-modified graphite pencil electrode system for detecting L-tyrosine in a solution such as phenylalanine, alanine, glucose, fructose, L-methionine, uric acid, ascorbic acid, sodium ion, lithium ion, sulfate, blood, plasma, serum, saliva, sweat, urine, washes of tissues, extracts of tissues, amniotic fluid, placental fluid, pharmaceutical composition, and dietary composition (all claimed), during treating diseases of a patient. Uses include but are not limited to alkaptonuria, albinism, psychiatric disorder, lung disease, liver disease, and tyrosinemia. ADVANTAGE - The system can reduce graphene oxide appeared on a graphene-modified graphite pencil electrode surface, where the graphene-modified graphite pencil electrode has enhanced electroactivity, sensitivity, and increased electroactive surface area as compared to a bare graphite pencil electrode. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for detecting L-tyrosine in a solution. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of ripple geometry of wrinkled graphene sheets.