A UV spectrophotometer is used to determine the absorption of light from a sample and can be used as a detector for HPLC. A sample is placed in the UV/VIS beam and absorbance versus wavelength is measured. A double beam spectrophotometer utilizes two beams of light: a reference beam and a sampling beam that passes through the sample. Some Double Beam UV spectrophotometer have two detectors that allow the two beams to be measured at one time.
