A number of organic compounds have been investigated for possible use as short wave-length cut-off filters in connection with fluorescence studies in the near ultraviolet region (3000–2300A). The absorption of these filter compounds has been studied, in the pure liquid state and in isooctane solutions of various concentrations, by means of a Beckman DU spectrophotometer. It was found that for a number of substances the cut-off wave-length can be shifted over a fairly wide range by varying the concentration of the solution. Curves are given for phenol, benzene, cumene, and thiophene. A table lists the cut-off wave-lengths for these compounds and also for chlorobenzene, dihydropyran, and mesitylene.
ARNOLD M. BASS, "Short Wave-Length Cut-Off Filters for the Ultraviolet," J. Opt. Soc. Am. 38, 977-978 (1948)