The present disclosure relates to systems and methods for analyzing fluids. The method for analyzing a chemical sample within a wellbore, contained within an interrogation device, may comprise broadcasting a coherent light from a frequency comb module, directing the coherent light through a fiber optic line to the interrogation device, irradiating the chemical sample with the coherent light, capturing light resulting from the irradiation of the chemical sample, and producing a spectrum resulting from the captured light from the chemical sample. A frequency comb system for analyzing a chemical sample may comprise a frequency comb module configured to broadcast a coherent light and a fiber optic line that extends into a wellbore to an interrogation device. The interrogation device may further be configured to contain the chemical sample for irradiation by the coherent light. The frequency comb system may further comprise a receiver and an information handling system.