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

In order to measure trace236 U and236 U/238 U 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 dissolution of sample with HF + HNO3  + HClO4 was followed by chromatographic separation with a single resin column containing normal type DGA resin (N,N,N',N'-tetra-n-octyldiglycolamide) as the extractant system. The analytical accuracy and precision of236 U/238 U ratios, measured as236 U16 O+ /238 U16 O+ , were examined by using the reference materials IAEA-135, IAEA-385, IAEA-447, and JSAC 0471. The low method detection limit (3.50 × 10-6  Bq kg-1 ) makes it possible to perform routine monitoring of environmental236 U due to global fallout combined with the Fukushima Daiichi Nuclear Power Plant accident fallout (>10-5  Bq kg-1 ). Finally, the developed method was successfully applied to measure236 U/238 U ratios and236 U activities in soil samples contaminated by the accident. The low236 U/238 U atom ratios ((1.50-13.5) × 10-8 ) and236 U activities ((2.25-14.1) × 10-2  mBq kg-1 ) indicate236 U contamination was mainly derived from global fallout in the examined samples.