Novel Trace Analysis Systems Based on Single Picoliter Microparticles Combined with Microflow Devices

本研究在光学显微镜下，通过红外激光照射可以产生单个的丁醇（BuOH）液滴，并且所产生的液滴可以同时被红外激光束捕获。然后将该技术与毛细管电泳系统相结合。在激光照射下产生了单滴的氢氧化钠，即使在渗透流的存在下也能稳定地捕获。然后用毛细管电泳分离铝二羟基偶氮苯螯合物（Al^<3+>-DHAB）或罗丹明B (RhB)，并强迫溶质分布到红外激光照射产生的单BuOH液滴上。以RhB为例，染料分布在BuOH液滴上的检出下限低至10^<-20>mol/dm^3，远低于普通毛细管电泳的检出下限。激光振荡在单染料掺杂阳离子交换树脂微球中也应用于超痕量分析。通过在自发宽发射光谱上叠加特征发射峰，证实了单掺杂rhb微粒在空气中的激光振荡。当空气中存在有机气体蒸汽时，由于粒子/周围介质折射率条件的变化，掺硼微粒的激光振荡特征峰被调制。本研究还扩展到空气中皮升气溶胶水滴的激光捕获显微光谱。我们成功地对气溶胶水滴进行了温度控制的激光捕获，并观察了低至223 K的过冷水滴的形成。

In the present study, we showed that a single 1-butanol (BuOH) droplet could be produced by infrared laser irradiation under an optical microscope and the droplet produced could be simultaneously trapped optically by the infrared laser beam. The technique was then combined with a capillary electrophoresis system. Single BuOH droplets were produced by laser irradiation and trapped stably even in the presence of an osmotic flow. An aluminum dihydroxyazobenzene chelate complex (Al^<3+>-DHAB) or rhodamine B (RhB) was then separated by capillary electrophoresis and the solute was then forced to distribute to single BuOH droplets produced by infrared laser irradiation. In the case of RhB, the lower detection limit of the dye distributed to the BuOH droplet was as low as 10^<-20>mol/dm^3, which was much lower than the ordinary detection limits in capillary electrophoresis.Laser oscillation in single dye-doped cation-exchange resin microspheres was also applied to ultratrace analysis. Laser oscillation of single RhB-doped microparticles under air was confirmed by characteristic emission spikes superimposed to the spontaneous broad emission spectrum. In the presence of organic gas vapor in air, the characteristic laser oscillation spikes from the RhB-doped microparticle were modulated owing to the change in the particle/surrounding medium refractive index conditions. The present study was also extended to laser trapping-microspectroscopy of picoliter aerosol water droplets in air. We succeeded in conducting temperature-controlled laser trapping of aerosol water droplets as well as in observing formation of supercooled water droplets down to 223 K.