Modification of the Fluorescence Attachment for the Beckman Model Du Spectrophotometer.

‘l.THEFOLLOWING describes a relatively simple amid inexpensive modification of the Beckman No. 2980 fluorescence attachment for the Beckman DIT spectrophotometer which permits rapid and easy imiterchange of both primary and secondary filters and increases the flexibility and adaptability of this instrument in fluorimetric analysis. The filter plate assembly for the secondary filters as originally supplied with the fluorescence attachment (Fig. 1, upper half) can be fitted with a maximnum of two filters. Changing of these filters in the standard attachment involves tile removal of the filter plate from the spectrophotometer photo tube housing and disassembly of the filter plate. The authors’ modifications of the secondary filter plate and filter carrier (Fig. 1, lower half) were accomplished after removal from tile photo tube housing and disassembly. The top and flat spring portion of the filter carrier were sawed off (Fig. 1, at center left). The tops of the rectangular filter compartments of the modified filter carrier were left open. A spring-haded friction contact was added at the top of the center vertical pillar between the filter compartments to maintain time vertical orientation of the filter carrier. The spring-