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  • 1 Lawrence Livermore National Laboratory Forensic Science Center P.O. Box 808 L-178 Livermore CA 94551 USA
  • | 2 Lawrence Berkeley National Laboratory M/S 70-193A 94720 Berkeley CA USA
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Abstract  

Capillary electrophoresis has been used to separate metal ions characteristically associated with nuclear fission. Electrokinetic injections and transient isotachophoretic techniques were employed to increase sample loading and provide on-column concentration of the analyte. On-line concentration factors of approximately 700-fold have been achieved. Indirect-UV absorbance, on-line radioactivity, and indirect laser-induced fluorescence detection were used to monitor analytes of interest. The radioactivity detector consists of a plastic scintillator and photomultiplier tube with a 4π detection geometry. The efficiency was determined to be approximately 80%, enabling samples resident in the detector window for 0.1 minutes to be reliably assayed. Detection of152Eu and137Cs was achieved at the low nCi level. Indirect fluorescence was performed with quinine sulfate as the background fluorophor with α-hydroxysobutyric acid added as a complexing agent. An argon ion laser was used as the excitation source with a diode array detector. Limits of detection for La3+, Ce3+, Pr3+, Nd3+, Sm3+, and Eu3+ were determined to be in the sub — 10 ppb range (6–11 nM) with indirect laser-induced fluorescence detection.