Determination of thorium isotopes

Buesseler KO, Cochran JK, Bacon MP, Livingston HD, Casso SA, Hirschbeig DJ, Hartman, MC, Fleer, AP (1992a) Determination of thorium isotopes in seawater by non-destractive and radiochemical procedures. Deep-Sea Res 139 1103-1114... 

Some of the methods commonly used for the determination of thorium in biological materials are given in Table 6-1. The colorimetric methods are not capable of isotope-specific determination of thorium isotopes. Alpha spectrometric and neutron activation analysis are useful in the quantification of isotope-specific thorium and thorium-232, respectively, and have better sensitivities than colorimetric methods. Alpha spectrometry is the commonly used isotope-specific analysis for the determination of thorium-232 and the thorium-230 derived from the decay of uranium-238 (Wrenn et al. 1981). Standard reference materials (SRMs) containing thorium in human liver (SRM-4352) and human lung (SRM-4351) necessary for the determination of absolute recovery in a given sample are available from the National Institute of Standards and Technology (Inn 1987). 

Hirose K. 1988. Determination of thorium isotopes in seawater by using preconcentration of thorium-XO complexes on XAD-2 resin. J Radioanal NucI Chem-Lett 127 199-207. 

Determination of Thorium Isotopes in Soil. Thorium was separated exactly as uranium except that the samples were spiked with Th radiotracer (instead of U), and 8 M and IM HNO3 were used in loading and eluting thorium (instead of lOM and 0. IM HCl in case of uranium), respectively. Thorium source was also prepared as that of uranium except that there is no need for the addition of TiCL solution. ... 

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