Determination of 236U in environmental samples by single extraction chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry

Abstract

In order to measure trace ²³⁶U in environmental samples with a high matrix effect, a novel and simple method was developed that makes the digestion and purification procedures compatible with advanced triple-quadrupole inductively coupled plasma-mass spectrometry. A total digestion of sample with HF + HNO₃ + HClO₄ was followed by chromatographic separation with a single column containing normal type DGA resin. The analytical accuracy and precision of ²³⁶U/²³⁸U ratios, measured as ²³⁶U¹⁶O⁺/²³⁸U¹⁶O⁺, were examined by using the reference materials IAEA-135, IAEA-385, IAEA-447, and JSAC 0471. The low method detection limit makes it possible to perform routine monitoring of environmental ²³⁶U due to global fallout and the Fukushima Daiichi Nuclear Power Plant accident. Finally, the developed method was successfully applied to measure ²³⁶U/²³⁸U ratios and ²³⁶U activities in 46 soil samples contaminated by the accident. The low ²³⁶U/²³⁸U atom ratios of (0.992?13.5) × 10^-8 and ²³⁶U activities of (0.469?24.4) × 10^-2 mBq kg^-1 indicate ²³⁶U contamination was mainly derived from global fallout in the examined samples.