| dc.description.abstract | Development gas sensor is currently focused on composite materials and
in recent years GO has been widely used as reinforcement and polyvinyl alcohol
(PVA) as matrix. Intended to improve performance of gas sensor which previously
used MOS materials. Study GO was prepared using Hummers-Offeman method
from graphite which was then blended with PVA to produce PVA-GO composite.
Composite was characterized by UV-Vis and FTIR, and then it was coated onto
surface of electrode by dripping and its thickness was measured. Performance of
PVA-GO gas sensor was studied by measuring water and coffee vapors (samples
coffee used were from Sidomulyo, Gumitir and Garahan plantations). PVA-GO
composite was successfully synthesized, showing UV-Vis absorption in reference
wavelength range 260 and 300 nm. Meanwhile, IR spectra PVA and GO also
appear on composite, with vibrations by group O-H, C=O, C=C, C-O-C, and C-H
stretching which were observed on 3290,67, 1721,64, 1650,12, 1086,96, and
2943,03 cm-1. Sensor optimization was carried out by varying composition, and
best composition was obtained at ratio of 0.75 g PVA:0.25 g GO, as indicated by
conductance value of 0.3566 x 10-7 S. Sensor with thickness of 0.132 mm has
highest conductance value of 0.6025 x 10-7 S, in standard measurements of coffee
vapor containing 3 g of coffee/45 mL of water. Consistency of sensor preparations
were carried out was successful indicated by RSD values of 3,14%-4,94% from
three preparations. Sensor is also sensitive enough to detect coffee aroma as
indicated by slope value of 0.0738 S.mL/g for Sidomulyo coffee. Finally, sensor is
also able to distinguish aroma of coffee from 3 different plantations as indicated
by conductance response, where response is 0.6265x10-7 S, 0.1723x10-7 S, and
0.08616x10-7 S for Sidomulyo, Gumitir and Garahan coffee. Lifetime is quite good
with RSD values in range 3,13%-3,56% of sample measurements for 6 weeks. | en_US |
