We investigated the effects of low-temperature baking, a standard treatment for superconducting radiofrequency (SRF) cavities, on niobium samples using synchrotron X-ray photoelectron spectroscopy. The study examined the chemical state of the niobium surface after chemical treatment with a buffered etching solution, which leaves a native oxide layer, fluorine impurities, and surface hydrocarbons. In-situ analysis was conducted during baking at 120°C for 48 hours in ultra-high vacuum. No significant changes in the core levels were observed; however, subtle variations were detected in the Nb 3d and C 1s spectra. Specifically, the most intense C 1s peak shifted to lower binding energies, indicating the formation of new chemical bonds. Additionally, partial transformation of Nb⁵⁺ to Nb⁴⁺ was observed, with no detectable oxygen depletion within the depth probed by XPS. The potential influence of X-ray exposure on the chemical state of these elements is also discussed.