| 摘要 |
An optical detection scheme for on-chip, high sensitivity refractive index detection is based on micro-interferometry, and allows for picoliter detection volumes and universal analyte sensitivity. The invention employs three main elements: a source (12) of coherent light, such as a VCSEL, laser diode or He-Ne laser; an etched channel (22) of capillary dimensions in a substrate (20) for reception of a sample to be analyzed; and a photodetector (25) for detecting laser light reflected off of the channel (22). The laser source (12) generates an unfocused laser beam (14) that is incident on the etched channel (22). A unique multi-pass optical configuration is inherently created by the channel characteristics, and is based on the interaction of the unfocused laser beam (14) and the curved surface of the channel (22), that allows RI measurments in small volumes at high sensitivity. The entire device, including the laser source (12) and the photodetector (25) can be formed on a single microchip. The detector has numerous applications, including universal/RI detection for CE (capillary electrophoresis), CEC (capillary electrochromatography) and FIA, physiometry, cell sorting/detection by scatter, ultra micro calorimetry, flow rate sensing and temperature sensing.
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