Adaptation of the Beckman Model B spectrophotometer to the measurement of dilute fluorescent solutions.

HE INCREASING USE of fluorimetry in routine analysis is reflected in a variety of commercially available instruments which, in many instances, are either prohibitive to the average laboratory due to high cost or lack proper sensitivity. Unlike the Beckman DU spectrophotometer, its clinical counterpart, known as Model B, is not provided with a standard fluorimetric attachment. The versatility of the latter instrument has already been demonstrated in this laboratory by a simple adaptation as a spectrofluorometer (1). To our knowledge, Model B has not been used for the quantitative appraisal of fluorescent solutions. The assembly herein described makes use of the standard electronic circuit of the spectrophotometer provided with a RCA IP28 photomultiplier attachment, a recent addition which considerably increases its range of sensitivity and allows the determination of quite dilute solutions of fluorescing material.