XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
295
T6: P–3
New spectrophotometric reagents based on Au nanorods and their
polyurethane foam nanocomposite for determination of catecholamines
Maria Gorbunova
1
, Vladimir Apyari
1
, Maria Matveeva
1
, Svetlana Gutorova
1
,
Grigory Antonyan
1
, Alexey Garshev
1,2
, Pavel Volkov
3
, Stanislava Dmitrienko
1
,
and Yury Zolotov
1
1
Department of Chemistry, Lomonosov Moscow State University, 119991 Leninskie gory, 1/3,
Moscow, Russia, e-mail: masha13_1992@mail.ru
2
Department of Materials Science, Lomonosov Moscow State University, 119991 Leninskie gory, 1/3,
Moscow, Russia
3
National Research Center “Kurchatov Institute” – IREA, 107076 Bogorodsky Val, 3, Moscow,
Russia
Gold nanoparticles are widely used in various fields of analytical chemistry due to their
unique optical properties conditioned by the surface plasmon resonance (SPR), which causes an
intense absorption in the visible spectral region. Spherical gold nanoparticles are usually used in
the analysis. There are much less investigations devoted to non-spherical nanoparticles.
Meanwhile, the extra optical properties of non-spherical gold nanoparticles, for example,
nanorods (AuNRs), caused by the presence of several modes of the surface plasmon oscillations
and several bands of the surface plasmon resonance could play a significant role in the
development of new methods for determination of different compounds. Immobilization of
nanoparticles in solid matrices could improve stability of these nanoobjects and provide
synthesis of nanocomposite materials with SPR properties.
The objective of this study was to investigate the possibility of using AuNRs and
nanocomposite material based on AuNRs immobilized on polyurethane foam for determination
of catecholamines by spectrophotometry and diffuse reflectance spectroscopy.
An interaction of catecholamines with silver nitrate in the presence of AuNRs results in
reduction of silver ions and formation of a silver layer on the surface of AuNRs. This process
leads to a hypsochromic shift of both maxima in the absorption spectrum of AuNRs, and to a
change of the colloid system color from pale-pink to green. The dependencies of the long-
wavelength SPR band maximum shift (Δλ, nm) on the concentration of catecholamines are
represented as curves with a bend, which is presumably caused by changes in morphology of the
surface silver layer and spontaneous nucleation of silver nanoparticles. These dependencies can
be used as non-linear calibration curves for the spectrophotometric determination of
catecholamines. The limits of detection are decreased as follows: dobutamine > adrenaline >
noradrenaline > dopamine, and are equal to 27, 18, 16, 13 μg L
–1
respectively. A new
nanocomposite material based on polyurethane foam modified with AuNRs has been
synthesized and its interaction with catecholamines in the presence of silver nitrate immobilized
in the nanocomposite has been studied. The results of this interaction are similar to those
described above, the limits of detection of dobutamine, adrenaline, noradrenaline and dopamine
by diffuse reflectance spectroscopy are 110, 70, 67 and 47 μg L
–1
respectively. This solid-phase
reagent is stable and easy-to-use. Effects of amino acids, organic and inorganic ions on the
determination of catecholamines by the both proposed techniques have been studied. Accuracy
of the determination was confirmed by the analysis of pharmaceutical formulations.
Keywords: surface plasmon resonance; spectrophotometry; diffuse reflection; au nanorods; nanocomposite;
catecholamines; determination
Acknowledgment
This work was financially supported by the Russian Science Foundation (grant N 14-23-00012).
The authors acknowledge instrumental support from M.V. Lomonosov Moscow State University Program
of Development.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
296
T6: P–4
Polyurethane foam modified with gold nanoparticles and its prospects
for the determination of thiols
Andrey Isachenko
1
,Vladimir Apyari
1
, Fedor Chikunov
1
, Pavel Volkov
2
,
Stanislava Dmitrienko
1
, and Yury Zolotov
1
1
Department of Chemistry, Lomonosov Moscow State University, 119991 Leninskie gory, 1/3,
Moscow, Russia, e-mail: sandrey91@gmail.com
2
National Research Center “Kurchatov Institute” – IREA, 107076 Bogorodsky Val, 3, Moscow,
Russia
Gold nanoparticles attract special attention of researchers with their unique properties, which
provide their broad application in various fields of chemistry. The observed effect of surface
plasmon resonance (SPR) underlies their use in spectrophotometry. High sensitivity of
nanoparticles in combination with the simplicity of their preparation makes them a promising
alternative to traditional spectrophotometric reagents. Along with nanoparticles, development
and studies of nanocomposite materials based on nanoparticles are actual. They often contribute
to the stabilization of nanoparticles and in some cases favorably improve their characteristics
expanding the possible applications of nanoparticles in the chemical analysis.
In this study, we investigated the possibility of preparation of polyurethane foam (PUF)
modified with gold nanoparticles by their in-situ formation and its use as an analytical form for
the determination of thiols by diffuse reflectance spectroscopy.
Gold nanoparticles immobilized on PUF were obtained by the borohydride method with
sodium borohydride pre-sorbed on PUF followed by the treatment of the modified polymer with
a solution of hydrogen tetrachloroaurate. Optimal conditions for the sorption of the reducing
agent on PUF were chosen as follows: 0.01 M sodium borohydride, 0.01 M sodium hydroxide,
0.0001 M cetyltrimethylammonium bromide, the sorption time – 15 min. Interaction of the
borhydride-modified PUF with hydrogen tetrachloroaurate for 30 min yields gold nanoparticles
of 11–13 nm in diameter on the surface of PUF. This results in appearing an SPR band in diffuse
reflectance spectra of the nanocomposite at 540 nm.
It has been found that the formation of gold nanoparticles on PUF is affected by thiols
(cysteamine, cysteine, mercaptopropionic acid, etc.), reducing the SPR band at 540 nm and color
intensity. This reaction takes place in mild conditions – at room temperature in aqueous solution
with a small amount of a thiol. All mentioned above allow us to consider PUF modified with
gold nanoparticles as a promising analytical form for the determination of thiols by diffuse
reflectance spectroscopy or naked-eye. The advantages of the proposed approach include
simplicity, high throughput, availability of the equipment used, and facility of implementation
for a test-version.
Keywords: surface plasmon resonance; diffuse reflectance spectroscopy; gold nanoparticles;
polyurethane foam nanocomposite; thiols determination
Acknowledgment
This work was financially supported by the Russian Science Foundation (grant N 14-23-00012).
The authors acknowledge instrumental support from M.V. Lomonosov Moscow State University Program
of Development.
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