Low Cost Spectrometer Accessor.
Hu, Pengxiang (Jerry).
- Point-of-care (POC) diagnostics integrated with smartphone platform has gained increasing attention in recent years due to its portability, cost-effectiveness and user-friendly setting. In this paper, we present an optical sensor based on a smartphone platform with extremely low-cost spectrometer accessary, which can be applied for colorimetric sensing. The spectrometer accessory enables separatio... read moren and quantification of color information from various samples, which are essential in many colorimetric and fluorescence-based detections. The proposed smartphone based optical sensor consists of LED as excitation light source, assembled spectrometer structure and transparent fluidic sensing chamber for liquid analyte. The functionality of this smartphone based optical sensor is proved by applying it for pH sensing, realized by injecting standard pH buffer solution into the fluidic sensing chamber prefilled with pH indicator dye. The color change of pH indicator in the sensing chamber can be distinguished by the imbedded spectrometer and the spectrum image can be captured using external smartphone camera without the need for expensive camera. Image-processing software is employed to obtain quantitative pH sensing result. In general, this smartphone based optical sensor can be used for any colorimetric sensors in food, agriculture and medicine. Furthermore, the cost of the sensor can be further reduced by replacing the sensing chamber with test strips, such as the ones made from paper, making it a highly practical sensing device for resource-limited settings. Submitted in partial fulfillment of the grant requirement of the Tufts Summer Scholars Program.read less