Long Optical Path Measurement

Spectrum of Potassium Permanganate

When the concentration of the sample is too low to be measured using a standard cell with an optical path length of 10 mm, a cell with a longer optical path length is used to enable measurement at the optimum absorption sensitivity. As shown in the figure, the absorption spectrum of potassium permanganate becomes clearer when a 100 mm cell is used instead of a 10 mm cell.