Analysis of triple-label samples by liquid scintillation spectrometry

The simultaneous analysis of three radionuclides present in a sample is demonstrated. The approach requires fitting a series of counting data acquired over a period of time to a triple exponential mathematical expression. The use and advantages of the method are illustrated for the case of the standardisation of 32P in the presence of 33P and 35S by 4π−β liquid scintillation spectrometry. The effects of sample preparation, chemical quenching and different activity ratios were studied.