ATR Probes
ATR means “Attenuated Total Reflection”. Light passing from a material with high refractive index (ATR crystal) to a material with lower refractive index (solution) is normally totally reflected. However, in practise, the light partially enters the solution and can be absorbed. The reflected light is therefore attenuated, causing a measurable reduction in the output signal dependent upon the absorbance of the solution.
ATR probes are suitable for situations involving the direct measurement of strongly absorbing solutions, where standard transmission probes cannot be used. The ATR probe 661.812 uses a 3-bounce sapphire ATR crystal, which is directly immersed into the solution to be measured.
