- Email: [email protected]
Synthesis of nitrogen-doped carbon nanocages for sensitive electrochemical detection of uric acid
Journal Pre-Proof Synthesis of nitrogen-doped carbon nanocages for sensitive electrochemical detection of uric acid Ruiyu Han, Jing Ma, Zhaoju Yang, Tong Cui, Wenjiao Liu, Shusong Wang PII: DOI: Reference:
S0167-577X(19)31135-8 https://doi.org/10.1016/j.matlet.2019.126520 MLBLUE 126520
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
5 June 2019 18 July 2019 7 August 2019
Please cite this article as: R. Han, J. Ma, Z. Yang, T. Cui, W. Liu, S. Wang, Synthesis of nitrogen-doped carbon nanocages for sensitive electrochemical detection of uric acid, Materials Letters (2019), doi: https://doi.org/10.1016/ j.matlet.2019.126520
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier B.V.
JOURNAL PRE-PROOF
Synthesis of nitrogen-doped carbon nanocages for sensitive electrochemical detection of uric acid Ruiyu Han a, Jing Maa, Zhaoju Yangb, Tong Cuic, Wenjiao Liuc, Shusong Wang a* NHC Key Laboratory of Family Planning and Healthy, Hebei Research Institute of
F
a
O
Family Planning Science and Technology, Shijiazhuang 050051, China. E-mail:
O
[email protected]
Clinical laboratory, Hebei General Hospital, Shijiazhuang 050051, China
c
School of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang,
PR
b
E-
050024, China
PR
Abstract:
In this work, nitrogen-doped carbon nanocages were prepared for uric acid detection,
AL
which exhibits three dimensional hollow nanostructures with large specific surface area of 565 m2 g-1 and unique heteroatomic property. The as-synthesized
R N
nitrogen-doped carbon nanocages show high selectivity and sensitivity for uric acid detection accompanied with excellent stability. The developed electrochemical
U
analysis for facile determination of uric acid shown a wide linear range of 0–1.0 mM,
JO
with the detection limit of 2.07×10−2 uM (S/N = 3). Moreover, this strategy was successfully used for uric acid detection in human serum and urine samples and demonstrated satisfied recoveries. The result in the present work suggests that nitrogen-doped carbon nanocages hold great potential to use as superior electrochemical sensors for uric acid determination. Keywords: Synthesis; Carbon materials; uric acid; Electrochemical detection; 1
JOURNAL PRE-PROOF
Sensors 1. Introduction Uric acid (UA; 2,6,8-trihydroxypurine) is the end product of purine catabolism in
F
human bodies and mainly exists in serum and urine. 1 Normal level of UA is of great 2
O
significance for body health, which is about 1.1 g, and near 15% is in the blood.
O
Excessive UA excretion dysfunction or production will result in some diseases
disease, Parkinson disease, and so on.
3
PR
including gout, atherosclerosis, high blood lipids/pressure, kidney disease, Alzheimer For this purpose, it is highly necessary to
E-
develop a sensitive and efficient method for UA determination.
PR
In recent years, electrochemical analysis has gained increasing attention for UA determination due to its briefness, rapidity, high sensitivity, and suitability for
AL
miniaturization. 4-6 On the other hand, thanks to high surface area, excellent electronic properties, and superior chemical stability, carbon nanomaterials have been widely
R N
used in many areas, such as energy storage and conversion, detection,
11
and sensor.
12-14
7
catalysis,
8-10
medical
Among abundant carbon materials, carbon nanocages
U
(CNCs) are cost effectiveness, easy for preparation, and have three-dimensional (3D)
JO
pore structure with large surface area and abundant active sites, which enables them to have great potential in the application of electrochemical sensors. As we all know, nitrogen-doping strategy can enhance charge delocalization and
create sufficient charge sites for carbon materials. It is believed that nitrogen-doped CNCs (NCNCs) would exhibit unique properties for detecting UA. As far as we know, there is few researches applied NCNCs for UA determination. Thus, it remains great 2
JOURNAL PRE-PROOF
challenges to develop facile, sensitive, selective, and stable UA detection strategy based on the NCNC materials. Herein, NCNCs were prepared by the pyrolysis of pyridine with the MgO template. The as-synthesized NCNCs shown high selectivity
F
and sensitivity for UA detection accompanied with excellent stability. The developed
O
electrochemical analysis exhibited a wide linear range of 0–1.0 mM with the detection
O
limit of 2.07×10−2 uM. And this strategy was successfully used for uric acid detection
PR
in human serum and urine samples and demonstrated satisfied recoveries. 2. Experimental section
PR
E-
The NCNC samples were prepared with MgO template:
Typically, 4.0 g basic magnesium carbonate (4MgCO3·Mg(OH)2·5H2O) was grinded
AL
and placed into the quartz tube in furnace, which was heated up to 900 °C at the
R N
heating rate of 10 °C min‐ 1, the flow rate of Ar is 100 sccm. At the same time, a syringe pump was used to introduce pyridine into the quartz tube for 4 min with the
U
feeding rate of 80 μL min‐ 1. Next, the products were collected after the reactor was
JO
naturally cooled down to room temperature, which was then immersed into 5 M HCl aqueous solution for 24 h to remove the MgO and washed by deionized water for 3-6 times. Finally, the obtained NCNC samples were dried at 85 °C for 12 h. For comparison, the nitrogen doped carbon (NC) sample was obtained without adding the basic magnesium carbonate. 3. Results and discussion 3
JOURNAL PRE-PROOF
Fig. 1 displays the morphological characterizations of the NCNC sample. As we can see from SEM (Fig. 1a) and TEM (Fig. 1b, c) images, the three-dimensioanl (3D) graphene nanosheets are comprised by plenty of hollow NCNCs with the size of ≈3
F
nm. The fringe spacing of the graphene walls is about 0.34 nm, which is ascribed to
O
the graphitic structure, and NCNC is about 7 to 10 graphene layers in thickness. In
O
contrast, there are no similar nanocages are found for CNCs (Fig. S2). Additionally,
PR
the energy-dispersive X-ray (EDX) spectroscopy elemental mapping is performed to visually probe the nitrogen in the NCNCs. As shown in Fig. 1d–f, N element is
specific
surface
area
of
NCNC
was
investigated
by
nitrogen
PR
The
E-
uniformly dispersed in the carbon framework.
adsorption/desorption with the Brunauer–Emmett–Teller (BET) strategy (Fig. 2a, b).
AL
We can observe high capillary condensation steps for NCNC sample, suggesting the well-developed and uniform nanocages and confirmed the TEM results. The NCNC
R N
sample has surface area of is 565 m2 g-1 and possesses the mesopore centred at 3 nm. In comparison, the NC synthesized without using the MgO template show a much
U
lower BET of 170 m2 g-1. The abundant mesoporous NCNCs are believed to be
JO
capable of enhancing the electrochemical detection of UA. XRD pattern of the NCNCs in Fig. S3a shows a broad peak at around 2θ=23.5°, corresponding to the (002) plane of the sp2 carbon. As demonstrated in Fig. S3b, the peak located at the range of 3500–3200 cm−1 represents to the N−H stretching vibration, and the bands at 1410 cm−1 is attributed to stretching vibration of C−N, 15 indicating the presence of the nitrogen in carbon nanocages. The chemical nature of the N species within the carbon 4
JOURNAL PRE-PROOF
host was studied by XPS as depicted in Fig. 2c, d. Three peaks located at 398.6, 399.5 and 401.2 eV in the high-resolution N 1s spectrum are observed for NCNC sample. These peaks are ascribed to pyridinic, pyrrolic, and graphitic N species, respectively.
F
16
O
The electrochemical detection of NCNCs toward UA were evaluated by CV
O
method. Fig. 3a displays the CVs profile of NCNCs modified GCE (NCNCs modified
PR
GCE and pure GCE are in the same plate) at various scan rates in 0.1 M PBS solution
E-
in the presence of 1.0 mM UA. According to the equation: 17
PR
Where ip stands for the anodic peak current (ipa) and cathode peak current (ipc), n is on behave of the electrons number, F is faraday constant, Q is electric quantity, v
AL
represents the scan rates, and T is the thermodynamic temperature. It was observed that value of ipa obviously increases with increasing the scan rates from 30 to 100 mV
R N
s-1. As shown in Fig. 3b, ipc = 4.8432×10−6 + 2.5326×10−7v (mV s−1) with R2 = 0.9993. The cathodic peak currents exhibit good linear relationship to scan rates, suggesting
U
the electro-catalysis of UA are surface electron transfer processes. In addition, the
JO
calculated n value is 2.03, thus the electro-catalytic behaviors of UA on the NCNCs modified GCE are concluded to be two electrons involved process. Fig. 3c was provided to illustrate that the anodic peak currents are increasing with the increase of the UA concentrations from 0 mM to 1.0 mM. From Fig. 3d, the linear regression equation for UA detection is Ipa = −2.685−0.7124CUA (mM) with a correlation coefficient of R2 = 0.9987. Limit of detection (LOD) is one of the most vital indicators, 5
JOURNAL PRE-PROOF
which reflects the sensitivity of analytic methods and instruments. 18 The LOD of UA at the NCNCs modified GCE in 0.1 M pH 7.0 PBS was calculated to be 2.07×10−2 uM (S/N = 3), which is more sensitive than the reported result based on the carbon dot
F
materials. 19 The results demonstrate that NCNCs possess high sensitivity for UA
O
determination.
O
For evaluating the practicality of this method, the NCNCs modified GCE was
PR
applied for detection of UA in human serum and urine samples after the employment of spectrophotometric method. The concentration of UA in serum and urine can be
E-
calculated, as shown in Table 1. The results revealed that there were no obvious
PR
differences for the analyzed UA content between such two methods, indicating that the NCNCs modified GCE could be potentially applicable for UA determination in
AL
human serum and urine samples. Note that the human serum and urine samples need to be diluted for obtaining the suitable concentrations before detection.
R N
4. Conclusion
In summary, we reported a facile synthesis strategy to prepare NCNCs by the
U
pyrolysis of pyridine with the MgO template. The NCNCs were used for sensitive and electrochemical
detection
of
UA
with
excellent
stability.
The
JO
selective
electrochemical analysis displayed a wide linear range of 0–1.0 mM and a detection limit of 2.07×10−2 uM. This strategy was also successfully used to determine the UA concentration in human serum and urine samples and shown satisfied recoveries. The findings in the present work demonstrate that NCNCs are promising sensor materials for superior electrochemical determination of UA. 6
JOURNAL PRE-PROOF
Acknowledgment This work was financially supported by the National Natural Science Foundation of China (No. 21471072 and 21571069). R. Y. Han and J. Ma contributed equally to this
F
work.
O
References
U
R N
AL
PR
E-
PR
O
1 M. I. Khan, Q. Zhang, Y. Wang, S. Saud, W. Liu, S. Liu, H. Kong, C. Wang, A. Uzzaman and H. Xiao, Sensor Actuat. B: Chem.,2019, 286, 9-15. 2 S. Jain, S. Verma, S. P. Singh and S. N. Sharma, Biosens. Bioelectron., 2019, 127, 135-141. 3 L. Fu, A. Wang, G. Lai, W. Su, F. Malherbe, C. T. Lin and A. Yu, Talanta, 2018, 180, 248-253. 4 M. Asif, A. Aziz, H. Wang, Z. Wang, W. Wang, M. Ajmal, F. Xiao, X. Chen and H. Liu, Microchim. Acta, 2019, 186, 61. 5 S. Huang, S. Song, H. Yue, X. Gao, B. Wang and E. Guo, Sensor. Actuat. B: Chem., 2018, 277, 381-387. 6 X. Gao, H. Yue, S. Song, S. Huang, B. Li, X. Lin, E. Guo, B. Wang, E. Guan, H. Zhang and P. Wu, Microchim. Acta, 2018, 185, 91. 7 Y. Bai, B. Shen, S. Zhang, Z. Zhu, S. Sun, J. Gao, B. Li, Y. Wang, R. Zhang and F. Wei, Adv. Mater., 2019, 31, 1800680-1800686. 8 B. Sen, S. Kuzu, E. Demir, S. Akocak and F. Sen, Int. J. Hydrogen Energy, 2017, 42, 23292-23298. 9 Y. Yildiz, H. Pamuk, O. Karatepe, Z. Dasdelen and F. Sen, RSC Adv., 2016, 6, 32858-32862. 10 H. Goksu, B. Celik, Y. Yildiz and F. Sen, ChemistrySelect, 2016, 1, 2366-2372. 11 H. Y. Yue, S. Huang, J. Chang, C. Heo. F. Yao. S. Adhikari, F. Gunes, L. C. Liu, T. H. Lee. E. S. Oh. B. Li, J. J. Zhang, T. Q. Huy, N. V. Luan and Y. H. Lee, ACS Nano, 2014, 8, 1639-1646. 12 H. Y. Yue, H. Zhang, J. Chang, X. Gao, S. Huang, L. H. Yao, X. Y. Lin and E. J. Guo, Anal. Biochem., 2015, 488, 22-27. 13 A. Savk, B. Ozdil, B. Demirkan, M. S. Nas, M. H. Calimli, M. H. Alma, Inamuddin, A. Asiri and F. Sen, Mater. Sci. Eng. C, 2019, 99, 248-254.
Z. Ulissi, F. Sen, X. Gong, S. Sen, N. Lverson, A. Boghossian, L. Godoy, G. Wogan, D. Mukhopadhyay and M. Strano, Nano Lett, 2014, 14, 4887-4894.
JO
14
15 G. Meng, S. Shi, R. Lalancette, R. Szostak and M. Szostak, J. Am. Chem. Soc., 2018, 140, 727-734. 16 X. Ning,Y. Li, J. Ming, Q. Wang, H.Wang, Y. Gao, F. Peng, Y. Yang and H. Yu, Chem. Sci. 2019, 10, 1589-1596. 17 Y. Liu, P. She, G. Jin, W. P. Wu, S. M. Xu, J. G. Li, K. Zhao and A. P. Deng, Sensor Actuat. B: Chem., 2015, 221, 1542-1553. 18 M. Shamsipur, N. Yazdanfar and M. Ghambarian, Food Chem., 2016, 204, 289-297. 19 C. Zhao, Y. Jiao, F. Hu and Y. Yang, Spectrochim. Acta A, 2018, 190, 360-367. 7
JO
U
R N
AL
PR
E-
PR
O
O
F
JOURNAL PRE-PROOF
8
JO
U
R N
AL
PR
E-
PR
O
O
F
JOURNAL PRE-PROOF
9
JO
U
R N
AL
PR
E-
PR
O
O
F
JOURNAL PRE-PROOF
10
JOURNAL PRE-PROOF
Highlights
JO
U
R N
AL
PR
E-
PR
O
O
F
Nitrogen-doped carbon nanocages (NCNCs) were prepared for electrochemical detection uric acid firstly. NCNCs deliver a three dimensional hollow nanostructure with large specific surface area and unique heteroatomic property. NCNCs show high selectivity and sensitivity for uric acid detection accompanied with excellent stability. NCNCs could be potentially applicable for UA determination in human serum and urine samples.
11
JOURNAL PRE-PROOF
Table 1. Detection of UA in human serum and urine samples by spectrophotometric method and as-prepared NCNCs modified GCE. RSD (%)
Recovery (%)
NCNCs modified GCE
RSD (%)
Serum
0.26
4.92
97.61
0.27
2.36
Urine
3.26
5.42
92.54
3.22
3.47
Recovery (%)
F
Spectrophotom etric determination
98.85
O
Sample
O
99.47
E-
JO
U
R N
AL
PR
There are no conflicts to declare.
PR
Declaration of Interest Statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Conflicts of interest
12
S0167-577X(19)31135-8 https://doi.org/10.1016/j.matlet.2019.126520 MLBLUE 126520
To appear in:
Materials Letters
Received Date: Revised Date: Accepted Date:
5 June 2019 18 July 2019 7 August 2019
Please cite this article as: R. Han, J. Ma, Z. Yang, T. Cui, W. Liu, S. Wang, Synthesis of nitrogen-doped carbon nanocages for sensitive electrochemical detection of uric acid, Materials Letters (2019), doi: https://doi.org/10.1016/ j.matlet.2019.126520
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
© 2019 Published by Elsevier B.V.
JOURNAL PRE-PROOF
Synthesis of nitrogen-doped carbon nanocages for sensitive electrochemical detection of uric acid Ruiyu Han a, Jing Maa, Zhaoju Yangb, Tong Cuic, Wenjiao Liuc, Shusong Wang a* NHC Key Laboratory of Family Planning and Healthy, Hebei Research Institute of
F
a
O
Family Planning Science and Technology, Shijiazhuang 050051, China. E-mail:
O
[email protected]
Clinical laboratory, Hebei General Hospital, Shijiazhuang 050051, China
c
School of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang,
PR
b
E-
050024, China
PR
Abstract:
In this work, nitrogen-doped carbon nanocages were prepared for uric acid detection,
AL
which exhibits three dimensional hollow nanostructures with large specific surface area of 565 m2 g-1 and unique heteroatomic property. The as-synthesized
R N
nitrogen-doped carbon nanocages show high selectivity and sensitivity for uric acid detection accompanied with excellent stability. The developed electrochemical
U
analysis for facile determination of uric acid shown a wide linear range of 0–1.0 mM,
JO
with the detection limit of 2.07×10−2 uM (S/N = 3). Moreover, this strategy was successfully used for uric acid detection in human serum and urine samples and demonstrated satisfied recoveries. The result in the present work suggests that nitrogen-doped carbon nanocages hold great potential to use as superior electrochemical sensors for uric acid determination. Keywords: Synthesis; Carbon materials; uric acid; Electrochemical detection; 1
JOURNAL PRE-PROOF
Sensors 1. Introduction Uric acid (UA; 2,6,8-trihydroxypurine) is the end product of purine catabolism in
F
human bodies and mainly exists in serum and urine. 1 Normal level of UA is of great 2
O
significance for body health, which is about 1.1 g, and near 15% is in the blood.
O
Excessive UA excretion dysfunction or production will result in some diseases
disease, Parkinson disease, and so on.
3
PR
including gout, atherosclerosis, high blood lipids/pressure, kidney disease, Alzheimer For this purpose, it is highly necessary to
E-
develop a sensitive and efficient method for UA determination.
PR
In recent years, electrochemical analysis has gained increasing attention for UA determination due to its briefness, rapidity, high sensitivity, and suitability for
AL
miniaturization. 4-6 On the other hand, thanks to high surface area, excellent electronic properties, and superior chemical stability, carbon nanomaterials have been widely
R N
used in many areas, such as energy storage and conversion, detection,
11
and sensor.
12-14
7
catalysis,
8-10
medical
Among abundant carbon materials, carbon nanocages
U
(CNCs) are cost effectiveness, easy for preparation, and have three-dimensional (3D)
JO
pore structure with large surface area and abundant active sites, which enables them to have great potential in the application of electrochemical sensors. As we all know, nitrogen-doping strategy can enhance charge delocalization and
create sufficient charge sites for carbon materials. It is believed that nitrogen-doped CNCs (NCNCs) would exhibit unique properties for detecting UA. As far as we know, there is few researches applied NCNCs for UA determination. Thus, it remains great 2
JOURNAL PRE-PROOF
challenges to develop facile, sensitive, selective, and stable UA detection strategy based on the NCNC materials. Herein, NCNCs were prepared by the pyrolysis of pyridine with the MgO template. The as-synthesized NCNCs shown high selectivity
F
and sensitivity for UA detection accompanied with excellent stability. The developed
O
electrochemical analysis exhibited a wide linear range of 0–1.0 mM with the detection
O
limit of 2.07×10−2 uM. And this strategy was successfully used for uric acid detection
PR
in human serum and urine samples and demonstrated satisfied recoveries. 2. Experimental section
PR
E-
The NCNC samples were prepared with MgO template:
Typically, 4.0 g basic magnesium carbonate (4MgCO3·Mg(OH)2·5H2O) was grinded
AL
and placed into the quartz tube in furnace, which was heated up to 900 °C at the
R N
heating rate of 10 °C min‐ 1, the flow rate of Ar is 100 sccm. At the same time, a syringe pump was used to introduce pyridine into the quartz tube for 4 min with the
U
feeding rate of 80 μL min‐ 1. Next, the products were collected after the reactor was
JO
naturally cooled down to room temperature, which was then immersed into 5 M HCl aqueous solution for 24 h to remove the MgO and washed by deionized water for 3-6 times. Finally, the obtained NCNC samples were dried at 85 °C for 12 h. For comparison, the nitrogen doped carbon (NC) sample was obtained without adding the basic magnesium carbonate. 3. Results and discussion 3
JOURNAL PRE-PROOF
Fig. 1 displays the morphological characterizations of the NCNC sample. As we can see from SEM (Fig. 1a) and TEM (Fig. 1b, c) images, the three-dimensioanl (3D) graphene nanosheets are comprised by plenty of hollow NCNCs with the size of ≈3
F
nm. The fringe spacing of the graphene walls is about 0.34 nm, which is ascribed to
O
the graphitic structure, and NCNC is about 7 to 10 graphene layers in thickness. In
O
contrast, there are no similar nanocages are found for CNCs (Fig. S2). Additionally,
PR
the energy-dispersive X-ray (EDX) spectroscopy elemental mapping is performed to visually probe the nitrogen in the NCNCs. As shown in Fig. 1d–f, N element is
specific
surface
area
of
NCNC
was
investigated
by
nitrogen
PR
The
E-
uniformly dispersed in the carbon framework.
adsorption/desorption with the Brunauer–Emmett–Teller (BET) strategy (Fig. 2a, b).
AL
We can observe high capillary condensation steps for NCNC sample, suggesting the well-developed and uniform nanocages and confirmed the TEM results. The NCNC
R N
sample has surface area of is 565 m2 g-1 and possesses the mesopore centred at 3 nm. In comparison, the NC synthesized without using the MgO template show a much
U
lower BET of 170 m2 g-1. The abundant mesoporous NCNCs are believed to be
JO
capable of enhancing the electrochemical detection of UA. XRD pattern of the NCNCs in Fig. S3a shows a broad peak at around 2θ=23.5°, corresponding to the (002) plane of the sp2 carbon. As demonstrated in Fig. S3b, the peak located at the range of 3500–3200 cm−1 represents to the N−H stretching vibration, and the bands at 1410 cm−1 is attributed to stretching vibration of C−N, 15 indicating the presence of the nitrogen in carbon nanocages. The chemical nature of the N species within the carbon 4
JOURNAL PRE-PROOF
host was studied by XPS as depicted in Fig. 2c, d. Three peaks located at 398.6, 399.5 and 401.2 eV in the high-resolution N 1s spectrum are observed for NCNC sample. These peaks are ascribed to pyridinic, pyrrolic, and graphitic N species, respectively.
F
16
O
The electrochemical detection of NCNCs toward UA were evaluated by CV
O
method. Fig. 3a displays the CVs profile of NCNCs modified GCE (NCNCs modified
PR
GCE and pure GCE are in the same plate) at various scan rates in 0.1 M PBS solution
E-
in the presence of 1.0 mM UA. According to the equation: 17
PR
Where ip stands for the anodic peak current (ipa) and cathode peak current (ipc), n is on behave of the electrons number, F is faraday constant, Q is electric quantity, v
AL
represents the scan rates, and T is the thermodynamic temperature. It was observed that value of ipa obviously increases with increasing the scan rates from 30 to 100 mV
R N
s-1. As shown in Fig. 3b, ipc = 4.8432×10−6 + 2.5326×10−7v (mV s−1) with R2 = 0.9993. The cathodic peak currents exhibit good linear relationship to scan rates, suggesting
U
the electro-catalysis of UA are surface electron transfer processes. In addition, the
JO
calculated n value is 2.03, thus the electro-catalytic behaviors of UA on the NCNCs modified GCE are concluded to be two electrons involved process. Fig. 3c was provided to illustrate that the anodic peak currents are increasing with the increase of the UA concentrations from 0 mM to 1.0 mM. From Fig. 3d, the linear regression equation for UA detection is Ipa = −2.685−0.7124CUA (mM) with a correlation coefficient of R2 = 0.9987. Limit of detection (LOD) is one of the most vital indicators, 5
JOURNAL PRE-PROOF
which reflects the sensitivity of analytic methods and instruments. 18 The LOD of UA at the NCNCs modified GCE in 0.1 M pH 7.0 PBS was calculated to be 2.07×10−2 uM (S/N = 3), which is more sensitive than the reported result based on the carbon dot
F
materials. 19 The results demonstrate that NCNCs possess high sensitivity for UA
O
determination.
O
For evaluating the practicality of this method, the NCNCs modified GCE was
PR
applied for detection of UA in human serum and urine samples after the employment of spectrophotometric method. The concentration of UA in serum and urine can be
E-
calculated, as shown in Table 1. The results revealed that there were no obvious
PR
differences for the analyzed UA content between such two methods, indicating that the NCNCs modified GCE could be potentially applicable for UA determination in
AL
human serum and urine samples. Note that the human serum and urine samples need to be diluted for obtaining the suitable concentrations before detection.
R N
4. Conclusion
In summary, we reported a facile synthesis strategy to prepare NCNCs by the
U
pyrolysis of pyridine with the MgO template. The NCNCs were used for sensitive and electrochemical
detection
of
UA
with
excellent
stability.
The
JO
selective
electrochemical analysis displayed a wide linear range of 0–1.0 mM and a detection limit of 2.07×10−2 uM. This strategy was also successfully used to determine the UA concentration in human serum and urine samples and shown satisfied recoveries. The findings in the present work demonstrate that NCNCs are promising sensor materials for superior electrochemical determination of UA. 6
JOURNAL PRE-PROOF
Acknowledgment This work was financially supported by the National Natural Science Foundation of China (No. 21471072 and 21571069). R. Y. Han and J. Ma contributed equally to this
F
work.
O
References
U
R N
AL
PR
E-
PR
O
1 M. I. Khan, Q. Zhang, Y. Wang, S. Saud, W. Liu, S. Liu, H. Kong, C. Wang, A. Uzzaman and H. Xiao, Sensor Actuat. B: Chem.,2019, 286, 9-15. 2 S. Jain, S. Verma, S. P. Singh and S. N. Sharma, Biosens. Bioelectron., 2019, 127, 135-141. 3 L. Fu, A. Wang, G. Lai, W. Su, F. Malherbe, C. T. Lin and A. Yu, Talanta, 2018, 180, 248-253. 4 M. Asif, A. Aziz, H. Wang, Z. Wang, W. Wang, M. Ajmal, F. Xiao, X. Chen and H. Liu, Microchim. Acta, 2019, 186, 61. 5 S. Huang, S. Song, H. Yue, X. Gao, B. Wang and E. Guo, Sensor. Actuat. B: Chem., 2018, 277, 381-387. 6 X. Gao, H. Yue, S. Song, S. Huang, B. Li, X. Lin, E. Guo, B. Wang, E. Guan, H. Zhang and P. Wu, Microchim. Acta, 2018, 185, 91. 7 Y. Bai, B. Shen, S. Zhang, Z. Zhu, S. Sun, J. Gao, B. Li, Y. Wang, R. Zhang and F. Wei, Adv. Mater., 2019, 31, 1800680-1800686. 8 B. Sen, S. Kuzu, E. Demir, S. Akocak and F. Sen, Int. J. Hydrogen Energy, 2017, 42, 23292-23298. 9 Y. Yildiz, H. Pamuk, O. Karatepe, Z. Dasdelen and F. Sen, RSC Adv., 2016, 6, 32858-32862. 10 H. Goksu, B. Celik, Y. Yildiz and F. Sen, ChemistrySelect, 2016, 1, 2366-2372. 11 H. Y. Yue, S. Huang, J. Chang, C. Heo. F. Yao. S. Adhikari, F. Gunes, L. C. Liu, T. H. Lee. E. S. Oh. B. Li, J. J. Zhang, T. Q. Huy, N. V. Luan and Y. H. Lee, ACS Nano, 2014, 8, 1639-1646. 12 H. Y. Yue, H. Zhang, J. Chang, X. Gao, S. Huang, L. H. Yao, X. Y. Lin and E. J. Guo, Anal. Biochem., 2015, 488, 22-27. 13 A. Savk, B. Ozdil, B. Demirkan, M. S. Nas, M. H. Calimli, M. H. Alma, Inamuddin, A. Asiri and F. Sen, Mater. Sci. Eng. C, 2019, 99, 248-254.
Z. Ulissi, F. Sen, X. Gong, S. Sen, N. Lverson, A. Boghossian, L. Godoy, G. Wogan, D. Mukhopadhyay and M. Strano, Nano Lett, 2014, 14, 4887-4894.
JO
14
15 G. Meng, S. Shi, R. Lalancette, R. Szostak and M. Szostak, J. Am. Chem. Soc., 2018, 140, 727-734. 16 X. Ning,Y. Li, J. Ming, Q. Wang, H.Wang, Y. Gao, F. Peng, Y. Yang and H. Yu, Chem. Sci. 2019, 10, 1589-1596. 17 Y. Liu, P. She, G. Jin, W. P. Wu, S. M. Xu, J. G. Li, K. Zhao and A. P. Deng, Sensor Actuat. B: Chem., 2015, 221, 1542-1553. 18 M. Shamsipur, N. Yazdanfar and M. Ghambarian, Food Chem., 2016, 204, 289-297. 19 C. Zhao, Y. Jiao, F. Hu and Y. Yang, Spectrochim. Acta A, 2018, 190, 360-367. 7
JO
U
R N
AL
PR
E-
PR
O
O
F
JOURNAL PRE-PROOF
8
JO
U
R N
AL
PR
E-
PR
O
O
F
JOURNAL PRE-PROOF
9
JO
U
R N
AL
PR
E-
PR
O
O
F
JOURNAL PRE-PROOF
10
JOURNAL PRE-PROOF
Highlights
JO
U
R N
AL
PR
E-
PR
O
O
F
Nitrogen-doped carbon nanocages (NCNCs) were prepared for electrochemical detection uric acid firstly. NCNCs deliver a three dimensional hollow nanostructure with large specific surface area and unique heteroatomic property. NCNCs show high selectivity and sensitivity for uric acid detection accompanied with excellent stability. NCNCs could be potentially applicable for UA determination in human serum and urine samples.
11
JOURNAL PRE-PROOF
Table 1. Detection of UA in human serum and urine samples by spectrophotometric method and as-prepared NCNCs modified GCE. RSD (%)
Recovery (%)
NCNCs modified GCE
RSD (%)
Serum
0.26
4.92
97.61
0.27
2.36
Urine
3.26
5.42
92.54
3.22
3.47
Recovery (%)
F
Spectrophotom etric determination
98.85
O
Sample
O
99.47
E-
JO
U
R N
AL
PR
There are no conflicts to declare.
PR
Declaration of Interest Statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Conflicts of interest
12