Effect of the scintillator on the instability of determination of 32P and 3H + 32P in liquid scintillation spectrometer

Abstract

The time course of the changes of the counting rate caused by 32P is determined in six commercially available scintillation mixtures applicable to aqueous solutions of the samples. The measurements were performed separately in the 3H- and 32P-measuring channels. Statistically significant changes were found during the first day after the sample preparation for Unisolve 100, Unisolve 1, and Aquasolve in both counting channels, and for Unisolve ELS in the 3H-channel. Minisolve and Instagel exhibited steady values during 60 and 78 h, respectively, and after that period the changes proceeded very slowly. The stability of the counting rates for Minisolve and Instagel was checked also for 3H alone and for combined 3H + 32P-labelled samples.