Development of Simple Optical Sensor for Measurement of Sugar Content Using Bent Optical Fiber, Light Emitting Diode and Photo Diode

抄録

To construct a simple optical sensor for measurement of the sugar content in an aqueous solution, a bent optical fiber was used as the sensor. The attenuation ratio, i.e., the differences in the light intensity through the bent optical fiber when the sensitive part (bent part) was soaked in a reference material and sample solution, was closely related of the solute content in the samples. However, slightly difference in the light intensity were observed in the practical application because the sugar content in foods and other bio-systems was much lower than that in the tested samples. Therefore, we constructed a sensor system using a light emitting diode (LED), photo diode (PD) and simple electronic circuit as a differential amplifier. As a result, measurement of the sugar content ranging from 0 to 30 g/dm³ was successful and excellent agreement between the FT-IR method as the conventional method and the sensor method using an operational amplifier (OP-amp) was observed. In addition, the time courses of the sugar content and the uptake rate of plant cells were able to be calculated during the cultivation process. The process monitoring for the fermentation process management will be possible by using this sensor. These results suggested that the developed sensor using a bent optical fiber is applicable as a simple and disposable optical sensor.