Ultra Sensitive Long Period Fiber Gratings Based Sensor for Detection of Adulterator in Ethanol

Abstract

An ultra-sensitive sensor based on long-period fiber graings (LPFGs) has been fabricated for the detection of methanol and water content in ethanol. Our sensor is very compact in size, highly accurate and easy to fabricate making it very useful than the conventional surface plasmon resonance (SPR) sensor, which is bulky and expensive. We show that our sensor is capable to achieve an ultra sensitivity of 696.34 pm/ V% methanol and 655.3 pm/ V% water in presence of methanol and water in ethanol respectively. Our sensor is capable of detecting minimum 1.5 × 10 −3 V% methanol and water in ethanol, which is far better than all the methods reported till now.

Influence of the configuration of metal sensing layers on the performance of a bimetallic (Ag–Cu) surface plasmon resonance biosensor

“…CSP considers both the sensitivity and the signal quality simultaneously, enabling a combinatorial sensing measurement. In figure 10, the CSP values of the Group-II sensor models were calculated for different analytes of (a) glucose concentration in urine (g dl −1 ) [27], (b) hemoglobin (Hb) concentration in blood (g dl −1 ) [28], and (c) methanol concentration in ethanol (%) [29] and plotted against their respective concentration values. The refractive index values corresponding to the concentrations are shown on the X-axis at the top.…”

“…Briefly, the SPR sensor used in this work consists of five components as shown in figure S1 in the supplementary information: (i) a PC prism with an index of refraction n = 1.58 [21], (ii) an adhesionpromoting interface layer of SiO 2 (20 nm) [22], (iii) Ag [23] and Cu (n = 0.091 915 + i3.5312) [24] as metallic sensing layers, (iv) a top encapsulating layer of ZnO (5 nm), n = 1.6248 + i0.016061 [25], for preventing the copper layer from oxidation, and (v) a final affinity layer to promote analyte binding and signal quality, which comprises a monolayer of 2D black phosphorous (BP) of thickness ∼ 0.53 nm, with n = 3.5 + i 0.01 [26]. The performance of SPR sensors with different design architectures were studied under analytes of various varieties like: air with n = 1, glucose concentration in urine [27], hemoglobin in blood [28], methanol concentration in ethanol [29]. The thickness dependence SPR curves for Cu and Ag are shown in figure S2 in the supplementary information.…”