In this study, we proposed a novel detection concept using aptamer DNA based on particle dissociation in a coupled acoustic-gravitational (CAG) field. When the CAG field was formed in the channel, the PS particles on the glass plate exerted the acoustic radiation force (F), sedimentation force (F), and binding force between the PS particle and glass plate (F). The applied voltage to the transducer (V) required for particle dissociation from the glass plate depends on the F. When the arginine is introduced to the system, in which the PS particles are immobilized onto the glass plate through the DNA hybridization using aptamer for arginine, the change in F can be induced, allowing us to detect the arginine concentration as the change in V. Thus, we demonstrated a detection concept for arginine that enables rough concentration estimation despite the limited precision.