The transformer is a vital device in the power system for transmission and distribution. 2-FAL (2-furfuraldehyde), and moisture are the crucial parameters that may be utilized to measure the transformer’s health. The insulation system of a transformer comprises transformer oil. Reliable transformer health monitoring is still challenging. Continuous monitoring of transformer insulation is needed to protect the transformer. Sensor-based tracking is one of the solutions. This paper proposes a comb-type capacitive sensor to identify moisture and 2-FAL concentration in oil. A simulation is performed in Ansys Maxwell Software. Then the proposed sensor is fabricated and experimentally tested in mineral oil samples that contain different concentrations of moisture and 2-FAL, to analyze the feasibility and characteristics of the sensor. A titanium oxide sensing film measures the moisture and 2-FAL traces in oil. The proposed TiO2 film-based sensor is simple, low-cost, and found to be highly sensitive to detect different concentrations of moisture and 2-FAL traces in mineral oil.