Transformers operating under challenging conditions often experience insulation degradation, leading to a shorter lifespan. Monitoring the existence of 2-Furfuryldehyde (2-FAL) in transformer oil, which is released because of the degradation of paper insulation and moisture, can propose valuable insights into the condition of transformer insulation. Since moisture and 2-FAL are contaminants with high dielectric constants, estimation using a capacitive sensor presents a feasible option. This study presents a study of using an Interdigital Capacitive Transducer (IDT) with Reduced Graphene Oxide (rGO) film-based IDT for measuring the concentration levels of 2- FAL and moisture. Further, a 555-timer circuit was developed to convert capacitance into voltage. The developed rGO thin film IDT sensor exhibits promising attributes, leading to sensitive measurement of 2-FAL and moisture concentration in oil. The successful implementation of the circuit shows that the sensitivity of rGO film IDT sensor is 0.268 mV/ppm for 2-FAL and 0.15 mV/ppm for moisture.