Simultaneous Laser Manipulation and Chemical Analysis of Single Microparticles in Solution

Simultaneous Laser Manipulation and Chemical Analysis of Single Microparticles in Solution

Noboru Kitamura¹

¹ Division of Chemistry, Graduate School of Science, Hokkaido University, Kita 10-Nishi 8, Kita-ku, Sapporo-shi, Hokkaido 060-0810

(Received 1 August 2005, Accepted 9 November 2005)

The analysis of individual microparticles in solution is in general very difficult because of their vigorous Brownian motions. Furthermore, the experimental results observed by a particle-unresolved method do not provide correct chemical and physical characteristics of the microparticles, since the results are the ensemble average of those for various microparticles with different sizes and properties. Therefore, a laser trapping/manipulation technique is an indispensable basis for analyzing various single microparticles undergoing vigorous Brownian motions in solution. Thus, the technique has been combined successfully with various analytical tools: steady-state and time-resolved absorption/fluorescence spectroscopies, Raman spectroscopy, and electrochemical techniques. In this review, the principles of laser trapping/manipulation and scanning laser micromanipulation techniques, including their instrumentation, are introduced. On the basis of such theoretical and experimental backgrounds, recent topics on single microparticle analyses are overviewed. In particular, the chemical and physical characteristics of single microparticles (ion-exchange resin beads, microdroplets, and so forth) in solution, revealed by laser trapping-microanalysis techniques, are described.

Keywords : laser trapping/manipulation; microspectroscopy; microelectrochemistry; single microparticles.