Fundamentals of ATR-FTIR Spectroscopy and Its Role …
23
Fig. 11 ATR-FTIR normalized spectra of the adsorption of BSA on TiO 2 nanoparticle surface at
varying time scales (10, 30, 60 and 90 min in red, green, blue, purple lines respectively) a without
phosphate and b with phosphate at the pH values of 7.4 (top), 4.5 (middle) and 2.0 (bottom spectra).
Adapted with permission from [54]. Copyright, 2017, American Chemical Society
cupric oxide (CuO) and zinc oxide (ZnO)) have been examined with three different
amino acids, l-Leucine (l-Leu), l-Cysteine (l-Cys), and l-Serine (l-Ser). In this
work, the effect of the differential behavior of CuO and ZnO nanoparticles individually with three amino acids is seen over the biomolecular fingerprint region of the
amino acid functional moieties in zwitterionic state at pH 5.8. The spectral analyses of
metal-oxide nanoparticles were made solely based on their impact over the carboxylate and ammonium functional groups of the respective amino acids taken for the
study. For l-Leu amino acid (10 mM), the fingerprint region (Fig. 12, panel a) showcased that the ZnO nanoparticles presented a significant impact over the pristine l-Leu
IR spectrum in comparison to CuO nanoparticles with a visible dominant peak at
~1106 cm
−1 and slight broadening observed around ~1600 cm
−1 , assigned to the antisymmetric carboxylate stretching mode (COO as
– ) of the amino acid. Considering the
l-Cys amino acid (0.1 mM) (Fig. 12, panel b), the IR absorption spectra displayed a
huge impact on ZnO than CuO nanoparticles with a high-intensity peak of bending
anti-symmetric (β as (NH 3
+ )) vibrational mode of an amino group (~1652 cm
−1 ), and a
shoulder peak at ~1585 cm
−1 of COO as
– . CuO nanoparticles were only seen to affect
the amino acid structure through the CH 2 wagging vibrational mode. For the case of
l-Ser amino acid (Fig. 12, panel c), both the oxide nanoparticles in the IR absorption
23
Fig. 11 ATR-FTIR normalized spectra of the adsorption of BSA on TiO 2 nanoparticle surface at
varying time scales (10, 30, 60 and 90 min in red, green, blue, purple lines respectively) a without
phosphate and b with phosphate at the pH values of 7.4 (top), 4.5 (middle) and 2.0 (bottom spectra).
Adapted with permission from [54]. Copyright, 2017, American Chemical Society
cupric oxide (CuO) and zinc oxide (ZnO)) have been examined with three different
amino acids, l-Leucine (l-Leu), l-Cysteine (l-Cys), and l-Serine (l-Ser). In this
work, the effect of the differential behavior of CuO and ZnO nanoparticles individually with three amino acids is seen over the biomolecular fingerprint region of the
amino acid functional moieties in zwitterionic state at pH 5.8. The spectral analyses of
metal-oxide nanoparticles were made solely based on their impact over the carboxylate and ammonium functional groups of the respective amino acids taken for the
study. For l-Leu amino acid (10 mM), the fingerprint region (Fig. 12, panel a) showcased that the ZnO nanoparticles presented a significant impact over the pristine l-Leu
IR spectrum in comparison to CuO nanoparticles with a visible dominant peak at
~1106 cm
−1 and slight broadening observed around ~1600 cm
−1 , assigned to the antisymmetric carboxylate stretching mode (COO as
– ) of the amino acid. Considering the
l-Cys amino acid (0.1 mM) (Fig. 12, panel b), the IR absorption spectra displayed a
huge impact on ZnO than CuO nanoparticles with a high-intensity peak of bending
anti-symmetric (β as (NH 3
+ )) vibrational mode of an amino group (~1652 cm
−1 ), and a
shoulder peak at ~1585 cm
−1 of COO as
– . CuO nanoparticles were only seen to affect
the amino acid structure through the CH 2 wagging vibrational mode. For the case of
l-Ser amino acid (Fig. 12, panel c), both the oxide nanoparticles in the IR absorption