Thermal Lens Microscope and Microchip Chemistry

Thermal lens spectrometry was realized under an optical microscope by controlling the chromatic aberration of the objective lens system. This thermal lens microscope (TLM) is ultrasensitive to non-fluorescent molecules and detection at even the yoctomole level in a liquid was confirmed. The TLM is widely applicable, almost the same as spectrophotometry, but its specificity for the analyte species is similarly poor. During development of the TLM equipment, a microchannel fabricated on a glass substrate was used as a sample vessel, which then became a microchemical chip. The generalized microchemical chip design method, micro unit operation (MUO) and continuous flow chemical processing (CFCP) was proposed and a variety of complex chemical processes for analyses, syntheses, and biomedical experiments could be integrated onto the microchemical chip. Therefore, the development of microchemical chips realized significant expansion of the field of microfluidics. Microchemical chips are also suitable devices for separation chemistry, and combination of the TLM and microchemical chips could compensate for the poor selectivity of TLM. These innovative methods will not only impact analytical chemistry but also microfluidics and most certainly other research fields such as biology and medicine. This account of The Chemical Society of Japan Award for Creative Work 2006 introduces these achievements.