Dr. Shingo Saito, Associate Professor

Dr. Shingo Saito

Electrophoresis for determination of ultratrace heavy metal ions in radioactive wastes and environmental microbes using novel fluorescent probes

Graduate School of Science and Engineering, Saitama University

*The organization and the title are those when awarded


  • 日本語
  • English


Ultratrace detection and speciation of trace heavy metal ions in small-volume samples containing a lot of interfering substances with low energy cost, rapidity and robustness is very difficult. In this study, a series of capillary and gel electrophoresis-fluorescence detection methods was developed using novel fluorescent metal probes, which fluorescently labeled target metal ions via complexing. The metal-probe complexes were successfully separated from the free probe and interfering ions, to be detected in ppt levels. Using these probes, determination methods for heavy metal ions in environmental, biological and nuclear spent fuel samples, and a speciation method for protein-bound copper ions in human serum were established.

Research summary

Electrophoresis is a separation method that utilizes the difference in ionic mobility in an electric field.

This method is widely used for separation analysis by combining with detectors such as fluorescence detector and optical absorption detector and others.

No method, however, provides high sensitivity sufficient for heavy metal ions in environmental water.

Dr. Saito has developed novel fluorescent probes that strongly bind with target heavy metal ions, which show no quenching of emission during binding.

Then he developed new electrophoresis methods that highly separate and detect the emissive metal-probe species.

In his method, hazardous heavy metal ions such as lead and actinide* ions can be analyzed with ultra-high sensitivity on the order of ppt, with only a small amount of sample.

It is expected to be applied to heavy metal ion analysis in water samples including radioactive-contaminated waste water. 

* Heavy metal elements with the atomic numbers from 89 to 103, including radioactive uranium and plutonium, are categorized as "actinide" series.