In this work, optical emission spectroscopy is used to study plasma-liquid precursor interactions in a plasma spray process. A mapping of the plasma jet is performed with a bundle of seven optical fibers while injecting various liquid precursors. Two suspensions containing a titania (TiO2) powder in different solvents and one solution containing titanium butoxide are analyzed. For each precursor, the evolution of both temperature and spectral line intensities along the plasma jet are observed. Comparing these results brings a new understanding of the precursor decomposition inside the plasma, while the noted contrasts between water and ethanol as solvent, and between the use of a powder and that of an alkoxide as a source of titanium, help to assess the effect of these parameters on the plasma spray process.