What is the most likely cause of loss of linearity in absorbance readings at high analyte concentrations in a spectrophotometer?

In spectrophotometry, the principle behind absorbance readings relies on Beer's Law, which states that absorbance is directly proportional to the concentration of an absorbing species in the solution. However, at high analyte concentrations, deviations from linearity can occur, which may lead to inaccurate measurements.

Stray light is a phenomenon where light that is not part of the light beam intended for analysis interferes with the absorbance measurement. When high concentrations of an analyte are present, their absorbance can be so high that they nearly saturate the detector. In such instances, any stray light that reaches the detector can significantly alter the detected absorbance, as the true absorption cannot be accurately reflected due to the overwhelming signal from the analyte. This results in a loss of linearity in the absorbance readings.

Other factors, while they can affect absorbance readings, do not specifically cause a loss of linearity in the context of high analyte concentrations. For instance, using the wrong wavelength may affect the accuracy of the absorbance reading but does not directly cause non-linearity related to high concentrations. Insufficient chromophore concentration and matrix interference may impact the measured values, but they are not typical causes for the deviation from linearity observed specifically at