Characterization of Ammonia Sensor Based on Quart Crystal Microbalance Coated with Polyvinyl Acetate Modified by Chitosan Laila Katriani (a), Rizky Aflaha (a), Ahmad Hasan As^ari (b), Pekik Nurwantoro (a), Roto (c), Kuwat Triyana (a*)
a) Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO Box BLS 21, 55281 Yogyakarta, Indonesia.
*triyana[at]ugm.ac.id
b) Research Center for Advanced Materials, National Research and Innovation Agency, Building 440-442 Kawasan Puspiptek Serpong, 15314 Tangerang Selatan, Indonesia.
c) Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO Box BLS 21, 55281 Yogyakarta, Indonesia.
Abstract
High sensitive and selective ammonia gas sensor has been fabricated and characterized based on Quart Crystal Microbalance (QCM) Coated with Polyvinyl Acetate (PVAc) Modified by Chitosan. Fabrication of nanofiber PVAc (15% w/w in DMF) on the QCM surface was carried out by electrospinning method with collector distance of 15 cm and a voltage of 15 kV. The low molecular weight of chitosan was modified by 1% w/w in 2% of acetate acid. Dilution of 1% chitosan to 0.1%, 0.2%, and 0.3%, followed by chitosan deposition used the drop case technique on QCM-PVAc. The results indicated that the best optimization was at 0.3% chitosan, which cause high sensitivity of sensor. QCM-PVAc/Chitosan 0.3% has a sensitivity of 1.7 Hz/ppm- and the linearity of 0.99 in the range (0 - 500) ppm. Meanwhile the limit of detection (LOD) and limit of quantitation (LOQ) 15 ppm and 46 ppm- response time was 7 seconds- good stability- great selectivity to ethanol, toluene, methanol, acetone, and water compounds. The addition of drop casted chitosan has increased the selectivity and sensitivity of the sensor.
