Thorin is primarily used as an indicator in analytical chemistry, particularly in complexometric titrations. It is employed to detect the presence of metal ions, such as thorium, uranium, and zirconium, due to its ability to form colored complexes with these metals. In water analysis, Thorin is utilized to determine sulfate concentrations by forming a reddish-pink complex with barium ions. Additionally, it is applied in spectrophotometric methods for the quantitative analysis of various metal ions in environmental and industrial samples. Its sensitivity and specificity make it a valuable tool in laboratory settings for precise metal ion detection and measurement.