An investigation of various wavelength-shifting compounds for improving counting efficiency when 32P-cerenkov radiation is measured in aqueous samples

Abstract

Various water-soluble wavelength-shifting compounds were investigated to assess their suitability for the improvement of counting efficiency when erenkov radiation from phosphorous-32 is measured in a liquid scintillation counter. Of these compounds esculin, β-methyl-umbelliferon and sodium salicylate led to the greatest improvement in counting efficiency. Especially esculin and β-methyl-umbelliferon are fairly stable under a variety of experimental conditions and improve counting efficiencies by a factor of about 1.3 and 1.2, respectively.

The use of ethanol as a water-miscible solvent combined with wavelength shifters soluble in both solvents does not improve counting efficiency.