carbon quantum dots as a novel coating for quartz crystal microbalance sensing of diethylamine vapour

In this work, a quartz crystal microbalance (qcm) based mass sensor was developed for measurement of volatile organic compounds (vocs). quartz crystal microbalance (qcm) is a mass sensor which measure the frequency of a piezoelectric quartz crystal [1]. the frequency of the piezoelectric crystal is decreased upon an analyte adsorption on its surface which are proportional to the mass of adsorbed analytes [2]. qcm sensors are interested, due to their low cost, small dimension, portability and high sensitivity. in order to improve the sensitivity and selectivity of qcm sensors, different materials have been coated on their surface. in this research, the crystal surface of the qcm was coated for the first time with carbon quantum dots and applied for determination of diethylamine vapour. carbon quantum dots were prepared from sugar and galega dry extract by a microwave synthesis method and characterized by fe-sem, edx, afm, uv-vis, fluorescence and ftir techniques. the prepared cqds showed superior sensing results due of their high-water solubility, very small sizes (around 5-20 nm), various functional group such as hydroxyl and amino groups and forming homogenous and smooth thin film on the crystal surface. the developed sensor had a linear response over 70 to 200000 μgl-1 towards dimethylamine vapour. the lod and loq of the developed method was 10 and 70 μgl-1, respectively. the sensor relative standard error was less than 15%. the developed sensor with low cost, high efficiency, good sensitivity could be applied for sensing of amine compounds in the different chemical industries, environmental and biological applications.