Real-time measurement of glucose concentration using position sensing detector

This study develops a high-precision, non-destructive measurement technique based on a PSD for determining the glucose concentration of a liquid solution from its refractive index. The optical metrology system is employed to measure the refractive indexes of samples with known glucose concentrations ranging from 10 ~ 100 g/l. By applying regressional analysis to the experimental results, an analytical expression is derived to describe the linear relationship between the refractive index and the glucose concentration. As the glucose concentration 50 g/l is applied, the error between the measured value of the refractive index and the analytically derived value is just 0.0004437627. An excellent agreement is observed between the experimentally determined values of the glucose concentration and the analytically predicted results.