Estimation of the Limit of Detection and effect of flow rate on micro cantilever sensor

Abstract

Limit of Detection (LOD) is the key parameter in chemical sensing instruments. The application of international union of pure and applied chemistry (IUPAC) recommended for univarient LOD estimations in the nonlinear semiconductor gas sensor. This methodology involves linearity, homoscedasticity and normality. This paper focuses on the analysis of LOD using omnicant instrument with selected Volatile Organic Compound (VOC) and the effect of flow rate of target VOC on detection sensitivity. For the experiment, acetone asVOC is selected as target gas, Polyvinylpyrrolidone (PVP) and honey are taken as coating materials on the fabricated sensor.Acetone, toluene, and isopropyl alcohol is considered as VOC which cause severe health hazardous to human life. The study about the concentration of acetone in the breathing environment is the necessity need, therefore acetone is selected for the study. This research work is targeted to check the effect of coating thickness and flow rate on the limit of detection of the testing instrument. As Honey and PVP are viscoelastic in nature, they exhibit more adhesive property. Hence these two materials are selected as coating materials for better sticking process. On the fabricated cantilever structure, PVP and honey are coated with a thickness of 600 nm, 900 nm and 1200 nm. The selected materials are tested against target gas acetone. From the LOD response of PVP and honey it is observed that, PVP shows a good sensitivity for lower thickness of coating whereas honey exhibits more sensitivity for higher thickness of coating .The effect on flow rate of the target VOCs viz., ethanol, toluene, acetone and isopropyl alcohol on detection sensitivity is studied and analyzed that increase in the flow rate of the target gas increases the detection sensitivity of the sensor.