| dc.description.abstract | The current development of gas sensors focuses on PVAc/GO composites as
sensor receptors. GO synthesized by Hummers-Offeman method use graphite and
characterized by UV-Vis and FTIR spectrophotometers. Composites made using
PVAc and GO blending methods with various compositions, and their thickness
through the coating process on the electrode surface. PVAc/GO sensor was then
tested and evaluated for performance using coffee samples from three different
plantations Sidomulyo, Gumitir, and Garahan. The successful synthesis of
PVAc/GO composites shown by presence of PVAc and GO spectra combination.
Results characterization using UV-Vis spectrophotometer showed two peaks at a
wavelength of 220 nm reflecting GO compounds and 260 nm indicating PVAc
compounds. Likewise, results of FTIR characterization show CH2 stretching
vibrations in the GO area 2927,37 cm-1, the peak 1224,44 cm-1 showing C-O-C
from PVAc, of wavelength 1726,55 cm-1 indicated carbonyl groups from PVAc and
GO, and at a wavelength 3255,01 cm-1 indicates the COOH groups of GO.
Optimization composition carried out by varying the mass ratio and obtained ratio
of 0,4 g GO and 0,6 g PVAc giving the highest response of 1,344 x 10-7 S. Likewise,
effect thickness and highest PVAc/GO sensor response obtained thickness of 0,13
mm with conductance value of 1,731 x 10-7 S. Consistency PVAc/GO sensor
preparation very good with repeatability of 3,46% and reproducibility of three
sensors tested using three coffees from different plantations had values range of
2,45% - 4,24%. PVAc/GO sensor is able to distinguish three aromas of coffee from
different plantations and has fairly high sensitivity indicated by a slope value of
0,7142 in detecting the aroma of Sidomulyo coffee. In addition, PVAc/GO gas
sensors also have a long lifetime, with %RSD values ranging from 4,25% - 4,30%,
for six weeks. | en_US |
