Modification of a Beckman Model DU Spectrophotometer for Automatic Operation at 210–2700 mμ

A Beckman Model DU quartz spectrophotometer has been modified to record absorption spectra from 210 to 2700 mμ automatically. This improvement has been achieved through replacement of the red-sensitive phototube with a lead sulfide cell, replacement of the ultraviolet-sensitive phototube with an IP28 photomultiplier tube, provision of a rotating, slotted drum to interrupt the light beam, and use of an electronic recorder. The null meter circuit of the spectrophotometer may be used if desired. All of the standard Beckman accessories may be used without modification.In view of the demonstrated resolving power, the ruggedness, and the relative low cost of this modified instrument, it is believed to open a new field for analysis.