Buzzin A, Asquini R, Caputo D, de Cesare G. Sensitive and Compact Evanescent-Waveguide Optical Detector for Sugar Sensing in Commercial Beverages.
SENSORS (BASEL, SWITZERLAND) 2023;
23:8184. [PMID:
37837014 PMCID:
PMC10574832 DOI:
10.3390/s23198184]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/13/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023]
Abstract
This work presents a compact and sensitive refractive index sensor able to evaluate the concentration of an analyte in a sample. Its working principle leverages on the changes in the optical absorption features introduced by the sample itself on the evanescent waves of a light beam. The device's high compactness is achieved by embedding the sample-light interaction site and the detector in a 1 cm2 glass substrate, thanks to microelectronics technologies. High sensitivity is obtained by employing a low-noise p-i-n hydrogenated amorphous silicon junction, whose manufacture process requires only four UV lithographic steps on a glass substrate, thus ensuring low production costs. The system's capabilities are investigated by sensing the sugar content in three commercial beverages. Sensitivities of 32, 53 and 80 pA/% and limits of detection of 47, 29 and 18 ppm are achieved. The above performance is comparable with state-of-the-art results available in the literature, where more complex optical setups, expensive instrumentation and bulky devices are used.
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