▎ 摘　　要

NOVELTY - A medical device consists of a graphene varactor (100) having a graphene layer (108a,108b) and a self-assembled monolayer comprising a compound(s) (C) containing hydrazine group(s) or hydroxylamine group(s), substituted hydrazine or hydroxylamine group(s), or their derivatives, provided on an outer surface of the graphene layer through electrostatic interactions between a partial positive charge on hydrogen atoms of hydrocarbon(s) of the self-assembled monolayer and a p-electron system of graphene. USE - Medical device is used for detecting aldehyde/ketone-bearing analytes in gaseous samples collected from patients during detection of diseases e.g. diabetic ketoacidosis. ADVANTAGE - The medical device has high sensitivity, and provides accurate detection of aldehyde and ketone-bearing analytes, thus allowing clinicians to provide appropriate therapeutic interventions, and hence leading to better treatment outcomes. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for modification of graphene surface for forming graphene varactor. DESCRIPTION OF DRAWING(S) - The drawing shows the schematic perspective view of graphene varactor. 100Graphene varactor 102Insulator layer 104Gate electrode 108a,108bGraphene layers 110Contact electrode