Comparison of three analytical techniques for determination of Th and U in environmental samples

Highlights: • Alpha-particle spectrometry, gamma-ray spectrometry and NAA for Th and U determination were compared. • Comparison includes detection limit, accuracy, repeatability and reproducibility. • The results show that NAA technique has the best accuracy. • U and Th concentrations are generally overestimated by both spectrometries. Alpha-particle spectrometry, gamma spectrometry and neutron activation analysis techniques for determination of Th and U in environmental samples have been compared. The analytical parameters studied include detection limit, accuracy, repeatability, reproducibility and surrogate recovery. The results show that neutron activation analysis technique has the best accuracy among the studied techniques; the other two techniques were assessed relative to it. The percentage difference between the three techniques results is about [-20, 20]. In addition, U and Th concentrations are generally overestimated by gamma spectrometry and alpha-particle spectrometry in all cases except Th concentration in the former technique, which is underestimated.