How do spectrophotometric titrations identify a reaction end point?

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In a spectrophotometric titration, the reaction end point is identified by monitoring changes in the absorption of the solution as a titrant is added stepwise to the analyte.1

To determine the end point, a titration curve is constructed by plotting the measured absorbance against the volume of the added reagent. The specific shape of this curve is determined by the individual absorbance characteristics of the titrant, the analyte, and the resulting reaction product. By analyzing the geometry of this curve, chemists can precisely identify the end point, which is then used to calculate the concentration of the analyte in the sample. This method is a form of spectrochemical analysis, providing an instrumental alternative to visual indicators or electrical measurements.12