New developments in the field of chemical infrared fiber sensors

摘要

Abstract: This paper describes the design of a fully reversible IR fiber optical chemical sensor for glucose based on the chemical modification of the fiber surface. The chalcogenide glass fiber (composed of As, Se, and Te) used in this experiment as an ATR element belongs to the new class of infrared transmitting glasses. A third of the fiber optic's length (10 cm) was used as an intrinsic sensing element and was successfully derivatized. The quality control of the first chemical process on the uncoated fiber surface, known as the silanization, was performed with scanning electron microscopy, secondary ion mass spectrometry and infrared microscopy. Homogenity of the silane layer (3-APTS) was checked by analyzing the silicone peak intensity. The immobilization of the glucose oxidase (GOD) via glutaraleldehyde and 3- aminopropyltriethoxysilane (3-APTS) was optimized after removing the protective polyamide coating of the fiber surface. This technique led to a stable glucose oxidase film on the fiber surface which was resistant to extensive water rinsing. Glucose solutions were pumped through a flow-through glass cell (ca. 0,5 ml) and continuous in-situ measurements were carried out with the use of an FTIR spectrometer (Bruker IFS-88) providing spectral information in real time. Glucose could be detected in the lower biological range by measuring the absorbance (at 1153 cm$+$MIN@1$/) of the gluconic acid which is produced by the glucose oxidation catalyzed by the enzyme (GOD) covalently bonded to the fiber surface. This work shows the strongly enhanced capability of chemically modified IR-fiber-optics for use as miniaturized biosensors.!20