Fiber optic sensor functionalized with glucose oxidase and gold nanoparticles for glucose and sucrose detections in daucus carota

Abstract

Tapered single mode fiber (SMF) immobilized with glucose oxidase enzyme (GOD) and gold nanoparticles (AuNP) for recognition of glucose and sucrose, respectively have been proposed in this work. Tapered fiber is fabricated using flame heating technique and is coated to improve the sensitivity of fiber based sensor. 3-(aminopropyl) triethoxysilane (APTES), GOD and AuNP are functionalized onto the tapered region of SMF through covalent interaction. The purpose of this study is to develop coated tapered fiber for determining the sensitivity and selectivity of glucose and sucrose in different concentration of glucose and sucrose solutions and in different types of Daucus carota. Solution concentration of 0.1 g/ml, 0.2 g/ml and 0.3 g/ml were used to differentiate the spectrum intensity of the fiber towards different amount of glucose and sucrose in the solutions. Baby carrots, imported carrots and organic carrots were used as an indicator to prove the existence of glucose and sucrose in these different types of Daucus carota. The experimental results demonstrate the sensitivities of GOD-immobilized fiber were 0.01045 , 0.11415 , 0.12689 and 0.16807 towards glucose solution, baby carrots, organic carrots and imported carrots, respectively. Meanwhile, the sensitivities of AuNP-immobilized fiber towards sucrose solution, baby carrots, imported carrots and organic carrots were 0.00840 , 0.000483 , 0.000698 and 0.000777 , respectively. The slopes obtained from the graph represent the sensitivities of the fibers towards different types of testing samples.