Isotopic analysis of plutonium in foods by inductively-coupled plasma mass spectrometry.

Pu isotopes in various foods were detected using a quadrupole ICPMS and Aridus II desolvation nebulizer. The method has ability to detect 239Pu and 240Pu at concentrations of ~52pg/kg (0.12Bq/kg) and ~9.5pg/kg (0.08Bq/kg) as well as 240Pu/239Pu ratio in <8h after receiving the samples. Foods were wet-ashed followed by DGA extraction for eliminating matrix, isobaric, and polyatomic interferences. A UH+ formation rate <10-5 and a 5-fold enhanced sensitivity for Pu was achieved after system optimization.