The maximum absorbance is set with the sample compartment empty. The maximum absorbance is measured when no light is transmitted to the phototube detector. It is set by adjusting the power switch/zero control knob until the instrument shows a reading of 0 %T (or infinite absorbance).
The Spectronic 20™ in the Self Check video is being set for maximum absorbance. Would any subsequent measurements be accurate? Why or why not?
Answer
Accurate absorbance measurements cannot be obtained. The maximum absorbance has been set off the scale of the spectrophotometer. Instead the maximum absorbance should be set to 0%T before making other measurements.
The Spectronic 20™ in the Self Check video is being set for maximum absorbance. Would any subsequent measurements be accurate? Why or why not?