Abstract: To investigate the gas and particle phase distributions of nicotine in mainstream cigarette smoke, an electrostatic precipitator (ESP) was upgraded with the addition of an automatic clearing puff device, and the operational conditions were optimized. A GC-MS method for determining nicotine in the gas and particle phases of mainstream cigarette smoke, based on the combination of the ESP and an impinger, was then established. The results showed that: 1) The ESP, when combined with the automatic clearing puff device, effectively achieved the separation of nicotine in particle and gas phases, thereby avoiding the occurrence of smoke aging. 2) With a voltage of -17.5 kV and using a bell-shaped tube and a spiral-shaped electrode, the ESP achieved a 100.00% trapping efficiency for particulate components in mainstream cigarette smoke, using solanesol as a marker. 3) The established method for determining nicotine in the particle and gas phases of mainstream cigarette smoke demonstrated good precision (RSD≤9.68%), with a limit of detection (LOD) of 0.034 μg/cig. The proportion of nicotine in the gas phase of mainstream smoke from various tested cigarettes was in the range of 0.35%-0.91%. 4) Compared to the control group, the total nicotine released in the mainstream smoke of a cigarette with an activated carbon filter decreased by 2.39%-10.69%, and the gas phase nicotine release decreased by 15.71%-48.56%. 5) For cigarettes with different ventilation levels, total nicotine release decreased with increasing ventilation level, while the proportion of gas phase nicotine remained relatively stable. The established method achieves the effective separation and determination of gas and particle phase nicotine in mainstream cigarette smoke, providing a useful reference for the design of cigarettes.