Chemiluminescence in the Auto-Oxidation of Luminol in Dimethyl Sulfoxide: Kinetic Effects of Alkalis, Quenching by Nitroblue Tetrazolium, and Elimination of Quenching by Hydrogen Peroxide

Article abstract of DOI:10.1134/S0036024420110308

Abstract: Conditions and ways of inhibiting, quenching, and subsequently restoring the chemiluminescence of luminol in alkaline aerated dimethyl sulfoxide are determined. Data are obtained that testify to the key role of electron transfer from luminol dia

Full text of DOI:10.1134/S0036024420110308

ISSN 0036-0244, Russian Journal of Physical Chemistry A, 2020, Vol. 94, No. 11, pp. 2369–2374. © Pleiades Publishing, Ltd., 2020.
Russian Text © The Author(s), 2020, published in Zhurnal Fizicheskoi Khimii, 2020, Vol. 94, No. 11, pp. 1716–1722.
PHOTOCHEMISTRY
AND MAGNETOCHEMISTRY
Chemiluminescence in the Auto-Oxidation of Luminol in Dimethyl
Sulfoxide: Kinetic Effects of Alkalis, Quenching by Nitroblue
Tetrazolium, and Elimination of Quenching by Hydrogen Peroxide
a,
a,b,
Yu. B. Tsaplev * and A. V. Trofimov **
a
Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334 Russia
b
Moscow Institute of Physics and Technology, Dolgoprudnyi, Moscow oblast, 141701 Russia
*
е-mail: tsap_04@mail.ru
*е-mail: avt_2003@mail.ru
Received February 28, 2020; revised February 28, 2020; accepted March 17, 2020
*
Abstract—Conditions and ways of inhibiting, quenching, and subsequently restoring the chemiluminescence
of luminol in alkaline aerated dimethyl sulfoxide are determined. Data are obtained that testify to the key role
of electron transfer from luminol dianions to oxygen in the auto-oxidation and chemiluminescence of lumi-
nol under these conditions.
Keywords: chemiluminescence, auto-oxidation, luminol, ion pairs, nitroblue tetrazolium, superoxide anion
DOI: 10.1134/S0036024420110308
INTRODUCTION
O
Many chemiluminescent reactions in the liquid
phase occur via auto-oxidation, and their initiation
and occurrence are due to dissolved oxygen. However,
the oxygen molecule (in the triplet state) interacts very
slowly with the singlet state of a substrate (e.g., the
bimolecular rate constant for the interaction between
NH
NH
−
+
2OH + O
2
NH O
2
CO2
−8
−1 −1
O and luminol monoanions is 10 M s [1]).
2
N + 2H O +
+ hν
2
2
When dimethyl sulfoxide (DMSO) was first used in
organic chemistry, it was found that auto-oxidation
processes proceed in alkaline DMSO much more rap-
idly than in water [2]. Alkaline DMSO was used as a
CO2
NH2
test oxidation system in the search for chemilumines- Independent variation of each of the initial concentra-
cence of many organic compounds (e.g., indoles [3]). tions of luminol, alkali, and oxygen showed that the
However, the reason for fast auto-oxidation (and che- reaction was of the first order in each of the reactants
miluminescence) remains unknown to date.
[5]. This was not confirmed (in either [5] or subse-
quent works) by primary kinetic data, but a kinetic
scheme of reactions was proposed (Scheme 1),
according to which the intensity of chemilumines-
cence in the quasi-stationary assumption is propor-
tional to the concentrations of luminol dianion, alkali,
The glow of luminol in alkaline DMSO was discov-
ered by White [4]. This reaction, which we refer to
below as the White reaction, was additionally studied
by four research teams [5–12]. White et al. [5] noted
that chemiluminescence was observed only in luminol
solutions that contained just over one mole of base per
mole of luminol. The oxidation of one mole of lumi-
nol consumes one mole of oxygen and two moles of
alkali, and the products of the reaction are nitrogen,
water, and 3-aminophthalate. It was shown that two
oxygen atoms in the aminophthalate molecule are
taken from the dissolved oxygen. The White reaction is
written formally as
and oxygen when k [H O] ꢀ k [O ]:
–1
2
2
2
Scheme 1.
−
−
k1
ꢂꢀꢀ
2−
LH + OH ꢀ ꢀꢁ L + H O,
2
k−1
2
−
k
2
2−
L + O
⎯ → AP + N
+ hν,
2
2
2369

2370
TSAPLEV, TROFIMOV
–
2–
2–
where LH , L , and AP are singly deprotonated
luminol, doubly deprotonated luminol, and 3-ami-
nophthalic acid, respectively.
100 000
Intensity i of chemiluminescence is related to reac-
1
2
tion rate w as
10 000
k k
−
−
1
2
i ~ w =
[LH ][OH ][O ].
2
k [H O]
−1
2
White and Burcey [6] assumed that the emitter of
the reaction was 3-aminophthalate producing light
from the electron-excited singlet state. Lee and Seliger
3
1
000
[
7–9] determined the quantum yield and recorded the
chemiluminescence spectra for several reactions.
These included the White reaction, for which the
quantum yield was 0.012 E/mol. It was established that
the emitter is 3-aminophthalate.
100
Lee and Seliger [9] also characterized the depen-
0
100
200
300
400
Time, s
dence of luminol chemiluminescence quantum yield
cl
Φ on the concentration of water in alkaline DMSO.
Fig. 1. Kinetics of luminol chemiluminescence in alkaline
DMSO in the presence of (1) 4.6 mM KOH, (2) 4.6 mM
NaOH, or (3) 7.7 mM LiOH and (1) 0.77, (2) 7.7, or
This proved that Φ grows as the concentration of
cl
water decreases, and it reaches a maximum at a con-
(
3) 77 nM luminol.
centration of 0.63 mol/L, below which water does not
affect Φ . However, it does affect the kinetics of che-
cl
miluminescence; e.g., as the concentration of water
rises from 0 to 0.14 mol/L, the maximum intensity of
chemiluminescence falls by a factor of 3 [10, 11].
prising two photon-counting heads, H7360-1 and
H7360-2 (Hamamatsu, Japan); a CNT-202 counter
(
Spetspribor, Belarus); and a computer. The chemilu-
Beck and Joó [12] studied the effect the concentra-
tion of oxygen has on the intensity of chemilumines-
cence in DMSO–EtOH and showed that instead of a
linear dependence (which would be expected from
Scheme 1), the dependence plateaus. Beck and Joó
minometer detected light in two spectral ranges, 430–
4
90 and 480–560 nm. The design of the chemilumi-
nometer was described in [13].
The reaction vessels were 2-mL polypropylene
assumed that the stage of interaction between the microtubes in which solutions of the reagents were
luminol dianions and oxygen is the equilibrium for- mixed. We typically added 50 μL of a DMSO solution of
2–
mation of the adduct (L O ):
luminol or luminol with nitroblue tetrazolium chloride
using a light-isolated injector to 600 μL of DMSO sup-
plemented with an alkali (LiOH, NaOH, or KOH) to a
concentration of 1–5 mM and (if required by the exper-
iment) hydrogen peroxide. The reaction mixture in a
microtube had small area of contact with air and a rela-
tively large volume, which complicated neutralization of
the alkali by atmospheric carbon dioxide and preserved
the stability of the alkali concentration for 10–20 min.
2
2
–
2–
2–
L
+ O ↔ (L O ) → AP + N + hν.
2 2 2
Neither inhibitors nor quenchers of chemilumines-
cence were found for the White reaction. It is known
only that the quenchers of triplets (including oxygen,
diphenyl ketone, acetophenone, diacetyl, pyrene,
anthracene, and iodide) and free radical scavengers do
not affect chemiluminescence at concentrations of up
to 1 mM [9]. The White reaction is the simplest and
most easily obtained chemiluminescent reaction, but
it has not found practical applications yet, likely due to
the lack of known ways to influence it. The aim of this
work was to find such ways.
In recording the light yield in the reaction of lumi-
nol with the LiOH solution, the reagents were mixed
outside the cuvette compartment of the chemilumi-
nometer, after which the reaction vessel was closed
with a stopper and placed in the cuvette compartment.
The electronic absorption spectra were recorded
with a Lambda 25 spectrophotometer (Perkin-Elmer,
United States). The solutions in alkaline DMSO were
handled in a quartz cuvette with an optical path length
of 1 cm; the cuvette was closed tightly with a ground
stopper.
EXPERIMENTAL
The following reagents were used in this work:
dimethyl sulfoxide (spectroscopy grade); LiOH,
NaOH, KOH, luminol, and hydrogen peroxide (30%)
(
all of chemically pure grade); and nitroblue tetra-
zolium chloride (analytically pure grade).
The kinetics of chemiluminescence was investi-
The concentrations of the reagent are indicated below
gated with a two-channel chemiluminometer com- as the initial concentrations in the reaction mixture.
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CHEMILUMINESCENCE IN THE AUTO-OXIDATION
2371
100 000
100 000
(а)
(b)
6
10 000
10 000
6
3
4
2
5
4
3
1000
100
10
1000
5
1
2
1
100
10
0
50
100
150
200
0
50
100
150
200
Time, s
Time, s
Fig. 2. Inhibition of luminol chemiluminescence (a) in the presence of KOH with additions of KI and (b) in the presence of NaOH
with additions of NaI. The initial luminol concentration was 0.77 nM in the KOH solution and 7.7 nM in the NaOH solution. The
concentration of alkali was 3 mM. The concentrations of KI were (1) 0, (2) 1.5, (3) 3, (4) 6, (5) 12, and (6) 24 mM. The concentra-
tions of NaI were (1) 0, (2) 0.38, (3) 0.77, (4) 1.5, (5) 3.1, and (6) 6.2 mM. The concentration of H O in DMSO was 0.17 M.
2
RESULTS AND DISCUSSION
within 500 s. More than 24 h were needed to record
the light yield in the presence of LiOH. At the same
time, the yield of luminol chemiluminescence quanta
in the presence of LiOH was ∼40% of those in the
presence of KOH or NaOH, for which the yields were
equal. This suggests there were no differences in the
efficiency of exciting the luminescence of luminol in
DMSO in the presence of KOH or NaOH, and in the
presence of LiOH, they were not as great as might be
expected. However, there were clear differences in the
light yield kinetics even between reactions in the KOH
and NaOH solutions. These differences could be due
to differences between the constants of association
Alkaline DMSO and Luminol
–
In water, anions with localized charge (HO ,
t-BuO ) form strong hydrogen bonds. In bipolar
–
aprotic solvents, they are not stabilized by hydrogen
bonds and readily participate in reactions of nucleop-
hilic substitution, addition, and deprotonation [14].
The deprotonation of luminol is an important step in
the considered luminescent reaction. The first ioniza-
tion constant of luminol is such that pK = 6.7, and
a1
luminol participates as a monoanion in most chemilu-
minescent reactions in aqueous solutions. The second
–
between the HO anions and the cations.
ionization constant of luminol is such that pK = 15.1
a2
(
at an ionic strength of 5 [15]), and the transition of
–
The formation of an ion pair from the HO anion
luminol to the doubly deprotonated form requires a
superbasic medium (e.g., alkaline DMSO).
+
and the M cation is described by the equilibrium
–
+
–
+
–
HO + M ↔ HO M . Concentration [HO ] of the
f
The chemical activity of alkalis in DMSO depends
on the hydration with water occurring in the solution,
and on the association into ion pairs caused by the
alkali metal cations. The constants of association of
1
free hydroxide ions is easy to find if constant of asso-
ciation K and total concentration of hydroxide B in the
solution are known:
−
+
+
+
HO anions and ions of K , Na , and Li in DMSO
–
–1
–2
–1 0.5
−
1
[HO ] = 0.5[–K + (K + 4BK ) ].
(1)
f
are 1400, 50000, and 790000 M , respectively [14],
because of which the effect of the formation of ion
pairs is apparent even in diluted solutions.
–
Concentration [HO ] changes not only when the
f
hydroxide concentration is changed, but when the salt
–
Let us compare the efficiency of the excitation of MX is added as well. Concentration [HO ] in a solu-
f
the luminescence of luminol in DMSO, depending on tion containing MOH and salt MX at concentration S
the type of alkali. Figure 1 presents the semi-log is given by the formula
kinetic curves of the glow after adding a portion of the
luminol solution to DMSO containing KOH, NaOH,
or LiOH. We can see that the reaction is fastest in the
presence of KOH, is noticeably slower in the presence
of NaOH, and is very slow in the presence of LiOH. In
the presence of KOH, almost all of the light is emitted
within 100 s; in the presence of NaOH, it is emitted
–
–1
–1
2
–1 0.5
[
HO ] = 0.5{–(K + S) + [(K + S) + 4BK ] }.
f
(
2)
1
Since the constant of hydration of the hydroxide ion exceeds
−1
1
600 M , a water molecule also accompanies the free (not par-
ticipating in an ion pair) hydroxide ion.
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A Vol. 94 No. 11 2020

2372
TSAPLEV, TROFIMOV
–
According to formula (1), concentrations [HO ] at by varying the concentration of NaI in NaOH and
f
points 2 obtained by varying the concentration of KI
B = 4.6 mM in the KOH and NaOH solutions were 1.5
in KOH lie on the same line, so k is proportional to
and 0.3 mM, respectively. So, the rate of luminol
d
–
deprotonation in KOH is five times higher than in concentration [HO ] . This is formally consistent with
f
NaOH.
Figure 2 illustrates the effect additions of NaI and
Scheme 1. The k value is independent of the type of
d
–
alkali, but it is determined by [HO ] . It is easy to see
f
KI to the KOH and NaOH solutions have on the from formula (1) that the first order of the reaction
kinetics of chemiluminescence. It is seen that with respect to alkali, which was identified by White
increases in the concentration of NaI in the NaOH et al. [5], is possible only at 4BK ꢀ 1.
solution and the concentration of KI in the KOH solu-
The above description concerns the effect of salts
tion are accompanied by a deceleration of the reaction
containing the same cation as the alkali. However,
and a reduction in the maximum intensity of chemilu-
adding lithium salts to alkaline DMSO containing,
minescence. However, NaI and KI are not quenchers;
e.g., KOH slows the reaction and lowers the maximum
they are inhibitors, since the intensity of emission in
intensity of chemiluminescence. This effect can be
the reaction remains virtually constant. The kinetic
used for determining lithium in nonaqueous solutions.
curves show that the intensity of chemiluminescence
after passing through the maximum falls exponen-
tially. The measured parameter was decay constant k
Nitroblue Tetrazolium and Luminol
d
of kinetic curve.
2+
Nitroblue tetrazolium (NBT ) is a well-known
Varying the concentration of KI in KOH and the chromogenic reagent for the superoxide anion [16,
concentration of NaI in NaOH leads to a symbate 17]. The structural formulas of NBT and the stable
–
change in k and concentration [HO ] calculated products of its reduction (monoformazan (MF) and
d
f
2–
according to formula (2). In Fig. 3, points 1 obtained diformazan (DF )) are shown below:
R
N N
N N
R
N N
N N
Ph
C
R
N N
N N
Ph C
C Ph +2e−
C Ph
R N N N N
H CO
3
OCH3
H CO
3
OCH3
NBT2+
MF
+
2e−
Ph
C
Ph
C
R =
NO2
R N N N N
N N N N R
H CO
3
OCH3
DF−
2
Li et al. [18] proposed a procedure for the spectro-
photometric determination of superoxide using an
NBT solution in DMSO. NBT is converted to MF at
a concentrations of superoxide lower than or equal to
the doubled concentration of NBT. The maximum of
the absorption of MF in DMSO is at ~680 nm. At a
concentration of superoxide exceeding a concentra-
tion of NBT four times greater, all of the NBT is con-
0
.10
0.08
0
.06
.04
0
2–
verted to DF , the maximum of whose absorption is
~730 nm.
1
2
0.02
It is known, however, that nitroblue tetrazolium in
DMSO in the presence of NaOH or KOH is converted
to monoformazan, and not diformazan [19, 20]. Fig-
ure 4 shows the spectra of NBT in alkaline DMSO
without and with luminol at different concentrations.
We can see the evolution of the spectra from the one
characteristic of MF with no luminol to the one char-
0
0.0002 0.0004 0.0006 0.0008 0.0010 0.0012
−
[
OH ] , M
f
Fig. 3. Dependence of k on the concentration of free hydrox-
ide ions, as determined by varying (1) the concentration of
NaI in NaOH and (2) the concentration of KI in KOH.
d
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CHEMILUMINESCENCE IN THE AUTO-OXIDATION
2373
14
0.4
0.3
0.2
5
12
10
4
3
8
6
4
2
2
1
1
2
0.1
0
1
2
3
4
5
6
7
8
[
NBT], μМ
0
5
Fig. 5. Dependence of the quenching of luminol chemilu-
00
600
700
800
900
minescence in alkaline DMSO on the concentration of
λ, nm
NBT. SS /SS is the ratio of the light yields in the reaction
0
without and with NBT. The initial luminol concentrations
were (1) 7.7 and (2) 31 nM. The concentration of NaOH in
DMSO was 3 mM.
Fig. 4. Spectra of NBT in alkaline DMSO (1) without and
2–4) with luminol. The NBT concentration was 4 μM.
The luminol : NBT ratios of concentrations were (2) 0.5,
3) 1, (4) 2, and (5) 4. The concentration of NaOH was
mM.
(
(
2
2
−
1
LO again. These reactions are presented below with
the rate constants [21]:
–
•
2–
8
–1 –1
acteristic of DF as the ratio of the luminol : NBT con-
centrations grows. The formation of diformazan in the
presence of luminol suggests that in the luminol dian-
2
L
→ L + L
(5 ×10 М s ),
–
6
–1 –1
L + HO → products (4 ×10 М s ),
2–
ion–oxygen adduct (L O ) postulated by Beck and
2
−
2
2−
–
2−
2
7
–1 –1
L + (HO ,O ) → LO H , LO
(5 ×10 М s ).
Joó, electrons are transferred to oxygen to form super-
2
2
–
•
It thus follows that the return of the half of the
oxide anions and luminol radical anions L .
–
formed diazaquinone to the light path at HO concen-
–
•
−•
2
trations of ~3 mM requires hydrogen peroxide at a
concentration of 0.24 mM. Figure 6 presents data on
the restoration of the light yield in the reaction with
NBT using hydrogen peroxide. We can see that at a
The interaction between L and O was studied in
[
1, 21]; it is characterized by a bimolecular rate con-
8
–1 –1
stant of 2.3 × 10 M
s
and produces peroxide
2
−
–
(
LO H , LO ), which plays a key role in luminol’s sufficiently high concentration of hydrogen peroxide,
2
2
the quenching caused by NBT is completely eli-
manated. The light yield is restored to 50% at a con-
centration of hydrogen peroxide of ~0.22 mM, which
is close to the calculated estimate.
chemiluminescence. We may assume that the removal
of superoxide anions by NBT should quench the che-
miluminescence in the White reaction, and this is
what happems. Figure 5 shows the dependence of the
yield of light in the reaction on the NBT concentration
in the Stern–Volmer coordinates. It is seen that NBT
is an efficient quencher that has a notable effect even
at concentrations of less than 1 μM, and this is the
only (currently known) quencher in the White reac-
tion that acts at such a concentration.
Scheme of Reactions
The scheme of reactions that includes Beck and
Joó’s refinement and evidence of the formation of
superoxide and luminol radical anions that was
obtained in this work can be written as
–
−
f
2–
When superoxide is removed from the reaction (in
this case, by NBT), the path of luminol consumption
changes. The luminol radical anions rapidly dispro-
portionate into diazaquinone L and L2− [21], and the
diazaquinone is then consumed in the reaction with
hydroxide ions [21]. Diazaquinone can be returned to
the light path of conversions using hydrogen peroxide,
LH + HO ↔ L + H O,
(3)
(4)
(5)
(6)
(7)
2
2
–
2–
L
+ O ↔ (L O ),
2 2
2
–
–• –•
(L O ) ↔ (L O ),
2
2
–• –•
2−
2
(
2−
L O ) → LO ,
2
–
2–
the reaction with which gives the peroxide LO H ,
LO2 → AP + N + hν,
2
2
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2
374
TSAPLEV, TROFIMOV
which chemiluminesces in the reaction with hydrogen
1
.0
peroxide.
0.8
0.6
0.4
0.2
FUNDING
This work was supported by the Russian Foundation for
Basic Research, project no. 19-53-18019_Bolg_a.
REFERENCES
. G. Merényi, J. Lind, X. Shen, and T. E. Eriksen,
J. Phys. Chem. 94, 748 (1990).
1
0
0.1
0.2
0.3
0.4
0.5
], mМ
2. A. Parker, in Advances in Organic Chemistry: Methods
and Results, Ed. by R. A. Raphael, E. C. Taylor, and
H. Wynberg (Inerscience, New York, London, Sydney,
[
H
2
O
2
1965), Vol. 5.
Fig. 6. Restoration of chemiluminescence in the presence
3
. R. F. Vasil’ev, A. V. Trofimov, and Yu. B. Tsaplev,
of NBT by hydrogen peroxide. SS is the light yield with-
0
Russ. Chem. Rev. 79, 77 (2010).
out NBT or hydrogen peroxide. The concentration of
NBT was 6 μM, the concentration of luminol was 7.7 nM,
and the concentration NaOH was 3 mM.
https://doi.org/10.1070/RC2010v079n02ABEH004064
4. E. H. White, J. Chem. Educ. 34, 275 (1957).
5
. E. H. White, O. Zafiriou, H. Kagi, and J. Hill, J. Am.
Chem. Soc. 86, 940 (1964).
−
f
where HO is a hydroxide anion that does not partici-
6. E. H. White and M. M. Burcey, J. Am. Chem. Soc. 86,
pate in an ion pair. The product of reaction (5) is in
941 (1964).
parentheses because we assume that it (along with
7. J. Lee and H. H. Seliger, Photochem. Photobiol. 4,
2‒
(
L O )) is an adduct. In DMSO, the separation of the
1015 (1965).
2
–
•
–•
2
8. J. Lee and H. H. Seliger, Photochem. Photobiol. 11,
2−
charge in adduct (L O ) to form (L O ) is an ener-
2
247 (1970).
getically advantageous process. Once the energy
advantage disappears when DMSO contains a suffi-
ciently high concentration of a solvent that forms
strong hydrogen bonds with anions (water, alcohol),
there is no charge separation in reaction (5), and there
is no chemiluminescence along path (3)–(7).
9
. J. Lee and H. H. Seliger, Photochem. Photobiol. 15,
27 (1972).
0. J. D. Gorsuch, Ph. D. Thesis (MIT Press, Boston, MA,
969). https://dspace.mit.edu/handle/1721.1/52931.
1. J. D. Gorsuch and D. M. Hercules, Photochem. Pho-
tobiol. 15, 567 (1972).
2. M. T. Beck and F. Joó, Photochem. Photobiol. 16, 491
1972).
3. Yu. B. Tsaplev, R. F. Vasil’ev, and A. V. Trofimov,
Russ. J. Phys. Chem. B 14, 431 (2020).
2
1
1
1
1
(
CONCLUSIONS
1
(
1) The strong-base hydroxide anion is responsible
for the deprotonation of luminol in alkaline DMSO.
Alkali metal cations form ion pairs with hydroxide
anions and act as inhibitors of chemiluminescence in
the White reaction. The kinetics of the chemilumines-
cence in the reaction is determined by the concentra-
tion of the hydroxide ions, which do not participate in
ion pairs.
1
4. B. A. Trofimov, A. M. Vasil’tsov, and S. V. Amosova,
Russ. Chem. Bull. 35, 682 (1986).
1
5. K. E. Haapakka, J. J. Kankare, and J. A. Linke, Anal.
Chim. Acta 139, 379 (1982).
1
6. C. Auclair and E. Voisin, Handbook of Methods for Ox-
ygen Radical Research, Ed. by R. F. Greenwald (CRC,
Boca Raton, FL, 1985), p. 123.
(
2) The interaction between luminol dianions and
1
7. M. Hayyan, M. A. Hashim, and I. M. AlNashef, Chem.
dissolved oxygen produces an adduct in which elec-
trons are transferred to oxygen to form luminol radical
anions and superoxide radical anions. The superoxide
radical anions were detected through the reaction with
nitroblue tetrazolium. The chemiluminescence in the
White reaction was efficiently quenched by nitroblue
tetrazolium.
Rev. 116, 3029 (2016).
1
8. R. H. Liu, S. Y. Fu, H. Y. Zhan, and L. A. Lucia, Ind.
Eng. Chem. Res. 48, 9331 (2009).
1
9. K. Umemoto and N. Okamura, Bull. Chem. Soc. Jpn.
59, 3047 (1986).
2
0. K. Umemoto, Y. Nagase, and Y. Sasaki, Bull. Chem.
Soc. Jpn. 67, 3245 (1994).
(
3) The quenching of chemiluminescence by 21. G. Merényi, J. Lind, and T. E. Eriksen, J. Biolumin.
nitroblue tetrazolium is relieved by hydrogen perox-
ide, confirming that the luminol radical anions form
because they disproportionate into diazaquinione,
Chemilumin. 5, 53 (1990).
Translated by V. Glyanchenko
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 94
No. 11
2020