As e-cigarettes (electronic nicotine delivery systems (ENDS) or e-vapor devices) are gaining popularity in global markets, there is an increasing need for quantitative analytical methods to measure e-cigarette fluid compositions for quality assurance (QA) testing and commercial product investigations. The objective of this work was to develop a highly efficient quantitative method that simultaneously determines the amount of major formulation and aerosol components of e-cigarettes including nicotine, propylene glycol (PG), glycerin, menthol, ethanol and water. The sample extracts of e-cigarette formulations and aerosols were analyzed using gas chromatography (GC) equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD). As this method quantitated six different formulation components of interest from a single sample preparation on a single instrument, it was referred to as the “6-in-1 method.” Results are reported as percent by weight for each component (weight %), milligrams per cartridge (mg/cartridge), milligrams per puff count (mg/puff count), or milligrams per e-cigarette (mg/e-cig). All requirements for method validation were met including linearity, accuracy, precision, limits of detection (LOD), limits of quantitation (LOQ), method robustness, and standard and sample extract stability. For example, the linearity was demonstrated for all analytes with a coefficient of determination of R²>0.995. The recoveries for all analytes ranged between 88-105%. The LOQs were 1.25 mg/cartridge for nicotine, PG, glycerin, menthol, and ethanol and 12.5 mg/cartridge for water. The integrated 6-in-1 method provides the following benefits: lower cost of analysis, reduced sample requirements, and improved laboratory productivity.