A downhole tool for analyzing reservoir fluids includes a mechanism for extracting a fluid sample (e.g., single phase liquid sample) from a wellbore, a sample depressurization module to liberate the gas phase from the extracted fluid sample, and a gas sensor utilized to detect one or more components of the gas phase. In certain embodiments, the downhole tool may be a formation testing tool, and the depressurization module may be a bubble point measurement module.