3.2. FT-IR studies
The characteristic FT-IR spectral signal of β-CD can be observed
in the spectra of Grp-β-CD (shown in Fig. 1c), justifying the
covalent interactions occurring between β-CD and CCG and no
physical adsorption of β-CD over graphene sheets. The characteristic
peaks of 3370 cm1 due to stretching vibration of O–H,
2925 cm1 due to C–H stretching vibration, C¼O stretching
vibrations gives a pick at 1720 cm1 bending stretching of C–H
from CH2 and CH3 gives a peak at 1420 cm1
, 1157 cm1 is due to
coupled stretching vibrations of C–O, C–C and C–O–H, and
938 cm1 peak represents skeletal vibration involving α-1.4 linkage
in Grp-β-CD. For CCG, the characteristic peaks are mainly at
3370 cm1 due to stretching vibration of O–H (a small peak due
to the presence of O–H groups in the graphene sheets after
deoxygenation of GO), and 1060 cm1 is due to stretching vibrations
from C–O, from the carboxyl groups remaining after hydrazine
reduction. The spectrum of our sensing matrix, Grp-β-CD
showed the mixed characteristic peaks of β-CD and CCG, indicating
the successful covalent attachment of these two (Guo et al., 2010).