Speed and precision: Unveiling an ICP-MS method for ultra-trace 239Pu quantification in food

A rapid, accurate, and sensitive inductively coupled plasma mass spectrometry (ICP-MS) method has been developed and validated for the determination of ultra-trace levels of Plutonium-239 ( 239 Pu) in food. After ashing, samples were digested with lefort aqua regia and treated with FeCl 3 to mask phosphorus (P) interference, thereby preventing it from inhibiting the adsorption of Pu by the resin column. Subsequently, a two-stage TK200 resin column was employed for separation and purification, followed by ICP-MS analysis using kinetic energy discrimination (KED) mode. By combining a chromatographic column with ICP-MS, this method achieved an overall decontamination factor (DF) of 3.53×10 12 for uranium hydride ions ( 238 UH + ) and demonstrated excellent linearity within the given concentration range, with a correlation coefficient ( r ) exceeding 0.999. The limit of detection (LOD) was 3.6 fg/g (ash), with an average recovery of over 74% and a relative standard deviation below 6.6%. Furthermore, the proposed method's applicability was evaluated by quantifying 239 Pu in food. The results indicate that this method is rapid, accurate, and sensitive, making it ideal for 239 Pu detection. • The ultra-trace 239 Pu in food was accurately and rapidly determined. • FeCl 3 was utilized as a masking agent to eliminate the interference of P in food. • TK200 columns were employed to achieve the separation of 239 Pu from 238 U in food samples. • Interference of 238 UH + was eliminated by ICP-MS.