The aerosols generated from e-cigarettes are primarily composed of fine particles of liquid and gas phases of the vaporized e-liquid. Low levels of thermal degradation products such as carbonyls (e.g. formaldehyde, acetaldehyde, acrolein, and crotonaldehyde) have been reported in e-cigarette aerosols. A rapid, selective and sensitive method specific to measuring carbonyls in e-cigarette aerosols using ultra performance liquid chromatography-mass spectrometry (UPLC-MS) has been developed. This method was optimized for aerosol collection using a 44 mm Cambridge filter pad (CFP) followed by an impinger containing acidified 2,4-Dinitrophenylhydrazine (DNPH) to capture both liquid and gas phase carbonyls, respectively. While the use of CFPs and impingers are common for traditional cigarette smoke collection techniques, environmental air sampling techniques typically involve the use of sorbent tubes (e.g. DNPH impregnated silica) for the collection of gas phase carbonyls as described in the U.S. Environmental Protection Agency (USEPA) Compendium Method TO-11A. Therefore, this collection regime was evaluated as an alternative to the traditional impinger approach for gas phase collection. It was demonstrated that both methods are suitable for the collection of gas phase carbonyls in e-cigarette aerosols and they show equivalent trapping efficiencies. For 20 puff collections, it was observed that approximately 70% of the formaldehyde is trapped in the liquid phase on the CFP and approximately 30% is trapped in the gas phase by either the sorbent tube or the impinger. The sorbent tube collection had one major limitation. The tubes had inconsistent packing densities which could restrict air flow, thereby altering the puff volume. While there are no puff volume issues using the impinger method, sorbent tubes must be pre-selected based on packing density prior to aerosol collection.