Question

Why is a double beam instrument more efficient at correcting for the blank than a single-beam?

Answer 1

Single beam spectrophotometer works by measuring the absorbance before and after the sample at two different times. The reference sample is first inserted and then the sample absorbance is measured. The correction for blank is done manually. A double beam spectrophotometer has two beams, one passing through the sample and the other from the reference, the instrument itself does the correcton of the blank and then measures the net absorbance by the detector. So the double beam with an automatic correction factor is more efficient and accurate than single beam spectrophotometer.