What is the function of methylene blue in spectrophotometry?
Methylene blue is used as an indicator for the presence of certain Ions such as the presence of HS – ion. spectrophotometry is used once the methylene blue has reacted to determine the quantity of said ion based on the intensity of blue that the reacion produces. Using a spectrophotometer you can determine the intensity and compare it with a set scale that has been calibrated with known concentrations of this ion.