Advances in Chemical Engineering and Science, 2012, 2, 453-460
http://dx.doi.org/10.4236/aces.2012.24055 Published Online October 2012 (http://www.SciRP.org/journal/aces)
Sensitive Voltammetric Determination of Mitoxantrone by
Using CS-Dispersed Graphene Modified Glassy
Carbon Electrodes
Bin Hong1,2, Qiong Cheng2*
1Department of Petrochemical Engineering, Changzhou University, Changzhou, China
2Department of Bio logical and Chemical Engineering, Jiaxing University, Jiaxing, China
Received May 10, 2012; revised June 13, 2012; accepted June 22, 2012
ABSTRACT
A novel CS-dispersed graphene modified glassy carbon electrode was fabricated. Study electrochemical characteristics
of mitoxantrone in the CS-dispersed graphene modified electrode by cyclic voltammetry and other methods, by select-
ing and optimizing the various parameters to create a new electrochemical method for the determination of mitoxan-
trone. The linear range of the oxidation peak current is from 6 × 10–10 to 1 × 10–6 mol/l in this method, after 2.5 mins
open-circuit accumulation, the limit of detection is 2 × 10–10 mol/l. After 10 parallel determinations, the relative stan-
dard deviation was 3.7% that the concentration of mitoxantrone was 1 × 10–8 mol/l. The modified electrode has been
successfully applied for the assay of mitoxantrone in human urine samples.
Keywords: Mitoxantrone; CS-Dispersed Graphene; Modified Electrode; Voltammetry
1. Introduction
Graphene, a new class of two-dimensional carbon nanos-
tructure, discovered by Geim [1], because of their out-
standing electronic transport properties, high mechanical
stiffness, and remarkable thermal and electrical conduc-
tivity, scientists are interested in graphene recently, due
to its fascinating physical properties [1-5] that is previ-
ously mentioned. It also has been predicted to have great
promise for many potential applications, for instance,
sensors, nanoelectronics, batteries, supercapacitors, hy-
drogen storage, and nanocomposites [6-9]. Carbon mate-
rials have been widely used in electroanalytical chemis-
try, especially in sensors, the electrochemical biosensors
utilizing nanomaterials have recently attracted consider-
able attention in the area of sensing [10,11], have been
used in biosensors in the food quality control and medi-
cine field. Graphene has been used to synthesis electro-
chemical sensors for ascorbic acid [12], β-NADH [12,13],
H2O2 [13], hydrazine [14], glucose [15,16], dopamine
[17,18], cadmium [19], Cytochrome c [20], chemical-
warfare agent [21], and others biosensors [22]. In order
to disperse graphene in different solvents, for example,
DMF, acetone, in this study, graphene were successfully
dispersed into chitosan. Then the CS-dispersed graphene
was fabricated. The CS-dispersed graphene film coated
onto the glassy carbon electrode, the electrochemical be-
haviors of analytes such as mitoxantrone were investi-
gated using the CS-dispersed graphene film coated elec-
trode, using a very sensitive and convenient voltampere
method to determine mitoxantrone.
Mitoxantrone belongs to anthraquinone derivative an-
ti-cancer drugs and its structure is given in Figure 1,
which can be connected with DNA molecules, as a result
of inhibiting the nucleic acid synthesis. Mitox antrone has
widely and efficient anti-cancer properties, it has been
employed for the treatment of leukemia and breast cancer
in clinical application. Therefore, the determination of
mitoxantrone is very important. Until now, there are
mainly three methods for detectting mitoxantrone as fol-
lows: chromatography [23,24], spectrophotometry [25],
Figure 1. Chemical structure of mitoxantrone.
*Corresponding author.
C
opyright © 2012 SciRes. ACES

B. HONG, Q. CHENG
454
electrochemical methods [26-29], however, the current
methods are not sensitive enough, or equipments are ex-
pensive, which are difficult to promote. So we are longed
for an effective, quick, inexpensive test method. This
study suggests us the new procedure, which is suitted for
the detection of mitoxantrone, has some advantages such
as ultrasensitivity, rapid response and excellent repro-
ducibility. A few years ago, the detection of mitoxan-
trone on ion implantation modified electrode had been
reported that it had a high limit of detection (1.8 × 10–8
mol/l). But the limit of detection of current methods is
lower than that of the reported method.
2. Experimental
2.1. Reagents and Apparatus
The mitoxantrone was purchased from South Zhejiang
Pharmaceutical Co., Ltd. A 1.0 × 10–4 mol/l standard
solution of mitoxantrone was dissolved into H2O and
kept in a refrigerator, 0.1mol/l sulfuric acid solution,
some working standard solutions were prepared by dilu-
tion with water, and all the aqueous solutions were pre-
pared with doubly distilled water. Graphite, hydrazine
hydrate solution (85 wt%) was purchased from Shanghai
Chemical Reagent Co., Ltd. CS-dispersed graphene was
fabricated from graphite. Chitosan (from Sinopharm
Chemical Reagent Co., Ltd.) solution was prepared by
dissolving chitosan in 1% acetic acid solution with mag-
netic stirring for 24 h. All the reagents were of analytical
grade.
A CHI 660A (Shanghai ChenHua Instrument Com-
pany) was used for the voltammetric determination,
scanning electron microscope (SEM), and a traditional
three-electrode system, CS-dispersed graphene modified
electrode, a saturated calomel reference electrode and a
platinum wire electrode were employed.
2.2. Prepartion of Film Coated CS-Dispersed
Graphene GCE
The GC electrode was mechanically polished 0.05 µm
alumina slurry, then rinsed and sonicated in purified wa-
ter, dried in the infrared lamp. The CS-dispersed gra-
phene came to form a black suspension by ultrasonica-
tion agitation for approximately 2 hours. A certain vol-
ume of the CS-dispersed graphene solution was diluted
to the appropriate concentration, was dropped onto a GC
electrode and the electrode was allowed to dry in room
temperature for 24 h to form a CS-graphene modified
electrode, noted as CS-GR/GC electrode. Chitosan (CS)/
GC electrode was also constructed as above procedure
except graphene in order to compare with the CS-GR/GC
electrode.
2.3. Procedure
CS-dispersed graphene modified electrode scanned cy-
clic voltammograms for several times (scanning range
from 0.50 to 0.90 V) in a 4 ml volume of 0.1 mol/l sulfu-
ric acid solution until the cyclic voltammograms curves
were stable. And added an amount of mitoxantrone stan-
dard solution. The scanning range of differential pulse
voltammograms from 0.60 to 0.85 V under open-circuit
while stirring the for 2.5 mins that were recorded after 15
s quite time, the oxidation peak height was measured at
about 0.74 V. After each detection, the CS-dispersed
graphene modified electrode scanned cyclic voltammetry
in acid solution to remove substance which adsorbed on
the electrode surface, as a result of activating electrode.
The process of preparation modified electrode which is
showed in Figure 2.
3. Results and Discussion
3.1. SEM Characterization of Graphene
The morphologies of graphene oxides, graphene were
examined by SEM. The typical SEM imagines of gra-
phene oxide (A) and the CS-dispersed graphene (B) on
the electrode Surface which is showed in Figure 3, re-
spectively. The morphology of graphene oxide is granu-
lar, but there is a small part of the sheet that can be seen
from the Figure 2. However, the most of the CS-dis-
persed graphene film is seem to be a flake-like shape
which is very different from the former. In addition, the
CS-dispersed graphene was fabricated through a simple
drop casting method on GCE exhibits a layer structure.
3.2. Electrochemical Responses of Mitoxantrone
The voltammetric behavior of mitoxantrone at the bare
GCE is investigated using cyclic voltammetry from 0.50
to 0.90 V and the results show that there is no obvious
oxidation or reduction responses of mitoxantrone. The
voltammetric behavior of mitoxantrone at the CS-dis-
persed graphene film coated electrode is also investigated
by CV. The CV from 0.50 to 0.90 V of a CS-dispersed
graphene film-modified electrode in a pH 1.0 Sulfuric
acid solution (without mitox antrone) is shown as curve a
in Figure 4, and no observable peak appears. When the
concentration of mitoxantrone is 1.0 × 10–6 mol/l, not
only appears an oxidation peak at 0.81 V from 0.50 to
0.90 V, but also appears a corresponding reduction peak
on the reverse scan at 0.72 V from 0.50 to 0.90 V, sug-
gesting that the electrode reaction of mitoxantrone at the
CS-dispersed graphene film is possible reversible.
The voltammetric responses of mitoxantrone have been
compared by differential pulse voltammogram (DPV)
which the results are showed in Figure 5. Both bare GCE
Figure 5(a)) and chitosan-film coated GCE (Figure (

B. HONG, Q. CHENG
455
O
HO
COOH
O
COOH
HO
sulfuric acid
potassiu m permanganate
Oxidation
O
HO
OH
NH
2
O
n
Reduction
Hydrazi ne hy drate
O
HO
OH
NH
O
n
CO
(A)
(B)
O
OH
OH
HN O CO
n
O
HO
OH
NH
O
n
O
OH
OH
HN O
n
CO
CO
(B)
GCE GCE
DPV
Mitoxantrone
Figure 2. The process of preparation modified electrode A is chitosan, B is CS-dispersed graphene, curve a is a bare GCE,
but curve b is a CS-dispersed graphene film coated GCE.
5(b)) are no observable oxidation current when the con-
centration of mitoxantrone is 1.0 × 10–8 mol/l. But under
the identical conditions, mitoxantrone appears a very
significant oxidation signal whose potential is 0.74 V at
the CS-dispersed graphene film coated GCE (Figure
5(c)). The significant oxidation peak current is undoubt-
edly attributed to characteristics of graphene. These sug-
gested that graphene has some special electrochemical
properties and big specific surface area which could pro-
vide much more reaction sites for the electrochemical
oxidation of mitoxantrone, then promote the exchange
rates of mitoxantrone, which results in increasing the
oxidation peak current greatly.
3.3. Effect of Supporting Electrolyte
To optimize the determination conditions of mitoxan-
trone, many support electrolytes were also tested, such as
HCl, H2SO4, HAc-NaAc, KCl, phosphate buffer, B-R
buffer, acetic acid-acetate buffer, others were not as
suitable as Sulfuric acid solution for the determination.
The pH value of the base solution has an important in-
fluence on the oxidation of mitoxantrone at the GCE
modified CS-dispersed graphene. The pH effect was stu-
died from 0 to 7.0. It showed that the highest oxidation
peak current of mitoxantrone was obtained at pH 1.0.
Hence, the Sulfuric acid solution pH of 1.0 was support-
ing electrolyte for determining mitoxantrone.
3.4. Accumlation Conditions
Accumlation conditions can affect the detection sensiti-
vity. Accumlation time and accu mlation po tential are two
important factors for the accumlation step. The effect on
peak current response from accumulation potential and
time which is studied by DPV, the concentration of mi-
toxantrone used was 1.0 × 10–8 mol/l.
When accumulation potential is shifted from +0.5 to
–0.5 V, the peak current keep stable. So accumulation at
open circuit is adopted. The peak current increases sharply
with increasing accumulation time which is illustrated in
Figure 6. The value of peak current reaches its maximu m
at 2.5 mins, and then levels off. This may be the electrode
surface become saturated. Thus, 2.5 mins under open-
circuit is generally chosen as accumulation condition.

B. HONG, Q. CHENG
456
0.5 0.6 0.7 0.8 0.9
-60
-40
-20
0
20
40
60
80
Peak current / A
Potenial / V
a
b
Figure 3. SEM images of: (A) GO and (B) CS-dispersed
graphene.
3.5. The Amount of CS-Dispersed Graphene
Dispersion on the GCE
The amount of CS-dispersed graphene dispersion on the
Figure 4. Cyclic voltammograms of a CS-di spersed graphene
film coated GCE. Curve (a) in pH 1.0 Sulfuric acid solution;
curve (b) a + 1.0 × 10–6 mol/l of mitoxantrone. Scan rate:
100 mV/s.
GCE surface determines the thickness of the cast film.
The amount of CS-dispersed graphene dispersion on the
GCE surface determines the thickness of the cast film.
The amount of CS-dispersed graphene has influence on
the peak current which is illustrated in Figure 7. When
the amount is from 0 to 8 µl which the peak current in-
creases remarkably with the increasing volumes of CS-
dispersed graphene suspension. But the peak current is
more stable and higher when the amount is from 8 to 30
µl, after that amount, it decreases. It has some relation-
ship with the thickness of the film. If the film was too
thin, the mitoxantrone amount adso rbed was small which
resulting in the small peak current. But when the film
Figure 5. Differential pulse voltammograms of 1.0 × 10–8 mol/l of mitoxantrone at different electrodes. Curve (a) a bare GCE;
curve (b) a chitosan (CS)-film coated GCE; curve (c) a CS-dispersed graphene film coated GCE. Accumulation times = 2.5
mins; pulse amplitudes = 50 mV, scan rates = 100 mV/s, pulse widths = 50 ms.

B. HONG, Q. CHENG 457
Figure 6. Influences of accumulation time on the oxidation peak current of 1 × 10–8 mol/l of mitoxantrone at the CS-dispersed
graphene film coated the GCE conditions are the same as in Figure 5.
Figure 7. Effects of amounts of CS-dispersed graphene sus-
pension on the oxidation peak current of 1 × 10–8 mol/l of
mitoxantrone. Other conditions are the same as in Figure 5.
was too thick, the film conductivity reduced and th e film
became not so stable as CS-dispersed graphene, so the
peak current decreases. Therefore, 8 µl CS-dispersed gra-
phene suspension solution was used in this study.
3.6. Influence of Scan Rate
The influence of scan rate on mitoxantrone oxidation at
the CS-dispersed graphene was investigated by cyclic
voltammetry which is showed in Figure 8. At scan rates
in the range from 10 to 500 mV/s. The oxidative peak
current of the CS-dispersed graphene in mitoxantrone
solution increases linearly with the scan rate, therefore,
the contribution of adsorption played a more important
role in the electrode process. From the symmetry of oxi-
dation peak and reduction peaks which indicates oxida-
tion and reduction of mitoxantr one on surface of the CS-
dispersed grapheme modified electrodes is not a com-
pletely reversible process. The peak potential has a slight
change with the increasing scan rates, thus, mitox antrone
on the CS-dispersed grapheme is the quasi-reversible
nature of the electrode reaction. The mechanism for the
oxidative peak process may be written as in Figure 9.
In summary, when the scan rates go up, peak current
increases, reversible becomes worse, peak shape be-
comes wide, at the same time considering signal-noise
ratio and other factors, so the best scan rates is 100 mV/s.
3.7. Calibration Graph and Stability
The relationships between the oxidation peak current and
the concentration of mitoxantrone were examined by us-
ing DPV which were demonstrated in Figure 10. When
the range is 1 × 10–6 - 1 × 10–7 mol/l, 2 × 10–8 - 8 × 10–8
mol/l, 8 × 10–9 - 6 × 10–10 mol/l, oxidation peak current (y)
and the concentration of mitoxantrone (x) have a good
linear relationship. Their linear equations and correlation
coefficients as follow: y = 1.099 + 19.03x, r = 0.9957; y =
5.482 + 0.1764x, r = 0.9903; y = 12.15 + 0.06702x, r =
0.9924. And its dete cti on limit is 2 × 10–10 m ol/l.
The relative standard d eviation of 3.7% for ten p arallel
determinations in mitoxantrone were studied by the same
modified electrode which exhibited good repeatability
and reproducibility, after two weeks, the average peak
current of the modified electrodes only increased 4.5%
from 20 parallel determinations. However, the peak po-

B. HONG, Q. CHENG
458
Figure 8. Cyclic voltammograms of mitoxantrone at CS-dispersed graphene modified electrode with scan rates (from inner to
outer): 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500 mV/s. respectively.
Figure 9. The mechanism for the oxidative peak process.
Figure 10. Differential pulse voltammograms (DPV) of dif-
ferent concentration values of Actinomycin D (ACTD) at
CS-dispersed grapheme modified GCE (from a to p): 0.08,
0.06, 0.2, 0.4, 0.6, 0.8, 2.0, 4.0, 6.0, 8.0, 10.0, 20.0, 40.0, 60.0,
80.0, 100.0 (× 10–8 mol/ L). Conditions are the same as in
Figure 5.
tential was almost constant which the modified elec-
trodes shows good stability.
3.8. Interferences
Interferences of some organic compounds influenced the
peak oxidation current of mitoxantrone solution which
was detected by cyclic voltammetry. Some common or-
ganic compounds in human body, such as urea, glucose,
VC, etc. The concentration of mitoxantrone solution is 1
× 10–6 mol/l, while the concentration of interfering sub-
stances is 100 times of the concentration of base solu-
tion. The result indicate that CS-dispersed grapheme af-
fect the detection of mitoxantrone hardly that in the pre-
sence of urea, glucose, VC. Thus, CS-dispersed graphene
modified electrode has good selectivity in detectting mi-
toxantrone.
3.9. Determination of Mitoxantrone in Urine
Samples
According to the observation above, it is found that the
CS-dispersed grapheme modified GCE has a high sensi-
tivity and selectivity in the laboratory. The CS-dispersed
grapheme modified GCE was used to detect urine sam-
ples which contained mitoxantrone (supported by Jiax-
ingfirst hospital) in order to test its practical application.
Mitoxantrone was diluted to a concentration in appropriate

B. HONG, Q. CHENG 459
Table 1. Determination of mitoxantrone in urine samples.
Sample Ideal concentration (mol/l)Found (mol/l) Recovery (%)
1 6.24 × 10–8 6.08 × 10–8 97.4
2 6.59 × 10–8 6.76 × 10–8 102.6
3 6.80 × 10–8 6.81 × 10–8 100.1
4 12.89 × 10–8 12.67 × 10–8 98.3
linear range by doubly d istilled water, then determine the
content of mitoxantrone in urine samples under the best
conditions, the results are demonstrated in Table 1, each
sample were parallel determined for three times, the re-
covery are in range from 97.4% to 102.6%.
4. Conclusion
Graphene were dispersed into chitosan which began to
obtain a stable and homogeneous CS-dispersed graphene
suspension. And finally the CS-dispersed graphene film-
coated electrode was fabricated. Because there are some
unique advantages exist in graphene, for instance, in-
credible electronic properties, big specific surface area,
strong adsorptive capacity, high migration rate and good
thermal conductivity rate, excellent mechanical and op-
tical-electrical properties. Graphene is used in modified
electrode and has a good prospect in analysis determina-
tion. And then a very sensitive and simple electrochemi-
cal method was developed to detect mitoxantrone in real
samples.
5. Acknowledgements
This work has been supported by the National Natural
Science Foundation of China (20275034), the Natural
Science Foundation of Zhejiang Province (Y405468),
Science and Technology Projects of Zhejiang Province
(2007F70008) and Science and Technology Projects of
Jiaxing (2008AY2017).
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