介绍了一种用玻璃毛细管成像法精确测量微量液体折射率的方法及测量装置。该方法以充入透明液体的毛细管构成柱透镜, 基于共轴球面光学系统的成像原理, 对光学成像系统的放大率进行单一参数的测量, 进而计算出待测液体的折射率。测量了纯水、乙醇、乙二醇、丙三醇的折射率, 各种待测样品的需要量均小于0.002 mL, 结果显示本试验装置的测量准确度与目前商用阿贝折射仪(±0.000 2)相当。另外, 测量了不同浓度的乙二醇水溶液的折射率, 并对测量的数据点进行了曲线拟合, 测试结果与阿贝折射仪测量结果和理论公式计算结果所拟合曲线吻合完好。该方法具有待测液体用量极少、操作方便和折射率测量精度高的特点, 适用于微量液体折射率的精确、快速测量。

A measuring method for the refractive index of micro-quantity liquid within a glass capillary was introduced. The capillary filled with liquid samples was used as a sphero-cylindrical lens in the system and a couple of objective lenses together with the glass capillary was used to image a micro-ruler onto a CCD imaging plane. As the image size and lateral magnification were very sensitive to the liquid filled in the capillary, the refractive index of the liquid could be exactly calculated by measuring the image-lateral magnification. The refractive indexes of four standard liquid media, pure water, ethanol, ethylene glycol and glycerin were measured, and experiments show that the accuracy of this equipment is the same as that of an Abbe refractometer(±0.000 2), and the quantity of liquid samples required by measurement is less than 0.002 mL. Moreover, the refraction indexes of a series of ethylene glycol with various concentrations were also calculated by this method and the results were compared with the values measured by the Abbe refractometer. These results demonstrate that the proposed method is characterized by micro-quantity sample required, easy operation and high measurement accuracy and it is suitable for the measurement of micro-quantity liquid quickly and exactly.