Development of Decommissioning and Radwaste Treatment Technology

10-2 Simplification of Analysis of Actinides in Radioactive Wastes－ Development of an Analytical Method using Capillary Electrophoresis －HNO

COOH

HNNS

Radiochemical analysis

Radioactivity data collection

Separation buffer
Sample solution

BeforeFused silica capillary(0.05 mm ID)

Inner wall

Emissive probe
for actinide ions
AdditionRadioactivity evaluation
for safe disposal

Emissive moiety

Injection(nL)

Radioactive
sample solution

After

Migration direction(+)

High voltage
10-30 kV(-)

Detection(Electropherogram)

Electrode
SeparationbufferCapillary electrophoresis (CE)Fig.10-4 Development of a simple and rapid analytical method using capillaryelectrophoresis
For the disposal of radioactive wastes, it is necessary to collect radioactivity datafrom radioactive waste samples. To reduce the radiation exposure of operators
during the analytical procedure, a simple and rapid analytical method for actinides
using capillary electrophoresis and new emissive probes was developed.

Chelating moiety

Fig.10-5 Emissive probe L for actinide
ionsProbe L is composed of an emissivemoiety for improved sensitivity and achelating moiety for connecting withactinide ions. Here, a probe with an acyclic
hexadentate chelating moiety is shown.

Fluorescence intensity

Radioactive waste samples

COOH

COOHOH

Separation by difference in electrophoretic speed
due to ionic charge and size

NCOOH

O

COOH

M+

Np - L

0.035

Am - LFree L
0.025

0.015
6.0

7.5

9.0

Migration time (min)Fig.10-6 Typical electropherogram ofactinide complexes of Am and Np
Am and Np were successfully detected
and separated using probe L. “Am-L”
represents an Am complex of probe L.

For the disposal of radioactive wastes, it is necessary tocollect radioactivity data from radioactive waste samples.
To reduce the radiation exposure of operators during theanalytical procedure, a simple and rapid analytical method of
detecting actinides using capillary electrophoresis (CE) has
been developed (Fig.10-4). Although CE has been employed
for the analysis of ionic species, including actinide ions,and has the advantages of high separation efficiency andsimplicity, there is no report of a high-sensitivity CE method
amenable to practical use for radioactive waste samples, to ourknowledge.
This study focuses on the capillary electrophoresis–
laser-induced fluorescent detection method (CE-LIF) forthe purpose of dramatically improving the sensitivity. Newemissive probes for the actinide ions, americium (Am) andneptunium (Np), suitable for CE-LIF were developed forthe first time. The emissive probes designed for detecting
actinides by CE-LIF are composed of an emissive moiety for
improved sensitivity, a chelating moiety for connecting withactinide ions, and a spacer between them. A chelating moiety,the more important moiety, is required for stability andprevents dissociation during migration. In this study, seventypes of newly synthesized emissive probes with different
chelating moieties were applied to CE-LIF. As a result, an
acyclic hexadentate probe (Fig.10-5) successfully detected
and separated Am and Np (Fig.10-6). Detection limits of
11 ppt and 4.7 ppt were obtained for Am and Np, respectively.
The sensitivity of this fluorescent detection method was about
90000–200000 times greater than that of a conventional UV
detection method. This method, with its short analytical time(within 10 min), has great potential for application to analysisof radioactive waste samples for the reduction of the radiation
exposure of operators.
Our research was performed as a part of a collaborative
study with Saitama University, “Separation and Detection
System for Actinide Ions by Capillary Electrophoresis Using
Novel Fluorescent Probes.”

Reference
Haraga, T. et al., Capillary Electrophoresis with Laser-Induced Fluorescent Detection Method using Highly Emissive Probes for Analysis of Actinides
in Radioactive Wastes, Proceedings of the ASME 14th International Conference on Environmental Remediation and Radioactive Waste Management(ICEM2011), Reims, France, 2011, ICEM2011-59092, 5p., in CD-ROM.
JAEA R&D Review 201399