Enhanced glucose sensing based on a novel composite CoII-MOF/Acb modified electrode

Article abstract of DOI:10.1039/c8dt00296g

In this work, we demonstrate the synthesis and application of a novel Co^II-based metal-organic framework {[Co₂(Dcpp)(Bpe)_0.5 (H₂O)(μ₂-H₂O)]·(Bpe)_0.5}_n (Co^II-MOF, H₄Dcpp = 4,5-bis(4′-carboxylphenyl)-phthalic acid, Bpe = 1,2-bis(4-pyridyl)ethane) as an electrochemical sensor for glucose detection. Single-crystal X-ray diffraction analysis shows that the Co^II-MOF has a two-dimensional (2D) bilayer structure composed of Co₂ units and Dcpp^4- ligands. There are two kinds of Bpe in the structure: one serves as a bidentate ligand linking two Co1 atoms in each 2D layer; the other is just free in the lattice. The Co^II-MOF modified glassy carbon electrode (GCE) shows good electrocatalytic activity towards glucose oxidation. To further improve the catalytic activity of the electrode, a new composite of Co^II-MOF/acetylene black (Co^II-MOF/Acb) was constructed. The Co^II-MOF/Acb modified electrode exhibits enhanced sensing behavior for glucose detection. The sensing performance of Co^II-MOF/Acb/GCE with different Acb loadings was investigated in detail. The results demonstrate that Co^II-MOF/GCE with 2% Acb (Co^II-MOF/Acb-2%/GCE) exhibits the best sensing behavior, including a high sensitivity of 0.255 μA μM^-1 cm^-2 and a wide linear range of 5-1000 μM, as well as a low detection limit of 1.7 μM (S/N = 3). It's worth noting that the linear range of Co^II-MOF/Acb-2%/GCE was extended by more than ten times when compared to that of Co^II-MOF/GCE without Acb addition. In addition, Co^II-MOF/Acb-2%/GCE shows good selectivity and stability in the sensing process.

Full text of DOI:10.1039/c8dt00296g

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Enhanced glucose sensing based on a novel
composite CoII-MOF/Acb modified electrode†
Cite this: DOI: 10.1039/c8dt00296g
Yuanyuan Wen, Wei Meng, * Chen Li, Lei Dai, Zhangxing He, Ling Wang, Ming Li
and Jing Zhu*
In this work, we demonstrate the synthesis and application of a novel CoII-based metal–organic frame-
work {[Co2(Dcpp)(Bpe)0.5 (H2O)(μ2-H2O)]·(Bpe)0.5 n
(CoII-MOF, H4Dcpp = 4,5-bis(4’-carboxylphenyl)-
}
phthalic acid, Bpe = 1,2-bis(4-pyridyl)ethane) as an electrochemical sensor for glucose detection. Single-
crystal X-ray diffraction analysis shows that the CoII-MOF has a two-dimensional (2D) bilayer structure
composed of Co2 units and Dcpp4− ligands. There are two kinds of Bpe in the structure: one serves as a
bidentate ligand linking two Co1 atoms in each 2D layer; the other is just free in the lattice. The CoII-MOF
modified glassy carbon electrode (GCE) shows good electrocatalytic activity towards glucose oxidation.
To further improve the catalytic activity of the electrode, a new composite of CoII-MOF/acetylene black
(CoII-MOF/Acb) was constructed. The CoII-MOF/Acb modified electrode exhibits enhanced sensing be-
havior for glucose detection. The sensing performance of CoII-MOF/Acb/GCE with different Acb loadings
was investigated in detail. The results demonstrate that CoII-MOF/GCE with 2% Acb (CoII-MOF/Acb-2%/
GCE) exhibits the best sensing behavior, including a high sensitivity of 0.255 μA μM−1 cm−2 and a wide
linear range of 5–1000 μM, as well as a low detection limit of 1.7 μM (S/N = 3). It’s worth noting that the
linear range of CoII-MOF/Acb-2%/GCE was extended by more than ten times when compared to that of
CoII-MOF/GCE without Acb addition. In addition, CoII-MOF/Acb-2%/GCE shows good selectivity and
stability in the sensing process.
Received 23rd January 2018,
Accepted 7th February 2018
DOI: 10.1039/c8dt00296g
rsc.li/dalton
metal active sites16 and tunable chemical compositions17 as
well as diverse structures.18 Based on these unique features,
1. Introduction
Diabetes mellitus is a kind of chronic disease, which is charac- MOFs have wide applications in absorption and
terized by hyperglycemia.1 Diagnosis of diabetes mellitus is separation,19–21 catalysis,22,23 molecular sensing,24,25 metal
based on blood glucose levels.2 Various approaches have been exchange,26,27 and so on.28–30 Redox-active MOFs present a
developed to monitor blood glucose.3–5 Electroanalysis is a high potential for electrochemical applications, especially in
facile and sensitive method, and electrochemical glucose the field of electrochemical sensors.31 It has been reported
sensors have undergone fast development in recent years.6,7 that redox-active MOFs exhibit excellent sensing performances
Among the numerous electrochemical glucose sensors, non- for the detection of hydrogen peroxide,32 bromate,33
enzymatic glucose sensors have attracted increasing interest acetaminophen34 and hydrazine.35 However, there are only a
due to their low cost, high stability and outstanding sensi- few reports on the use of MOFs as direct glucose sensors.36–39
tivity.8 Many materials, such as metals,9,10 metal oxides11,12 Yuan et al. first described a three-dimensional Cu–MOF that
and polymers13 have been fabricated and applied as the elec- had electrocatalytic activity towards glucose oxidation.36 Pang
trode material for glucose sensing.
et al. used an ultrathin Ni–MOF for glucose sensing, which
Metal–organic frameworks (MOFs) are promising crystalline exhibited a superior analytical performance.37 In order to
materials formed by the assembly of metal ions and organic explore more excellent glucose sensors based on metal–
ligands.14,15 MOFs possess inherent advantages, such as rich organic frameworks, the design and synthesis of various MOFs
as new electrode materials is practically important.
The strategy for enhancing the sensing performance of
College of Chemical Engineering, North China University of Science and Technology,
MOFs as electrochemical sensors is always an issue of
concern, and the key point is to improve the conductivity of
MOFs. Nowadays, an effective strategy is to immobilize MOFs
Tangshan 063009, PR China. E-mail: 2007mengwei@163.com, tszhujing@163.com;
Fax: +86 315 8805462; Tel: +86 315 8805462
†Electronic supplementary information (ESI) available. CCDC 1581496. For ESI
on carbon materials, and the most commonly used carbon
and crystallographic data in CIF or other electronic format see DOI: 10.1039/
materials are carbon nanotubes,40 macroporous carbon41 and
c8dt00296g
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graphene.42 Acetylene black (Acb), a special type of conductive refined using a full-matrix least-squares technique based on
carbon black, has become an important conductive additive F2. The crystallographic data for CoII-MOF are listed in
due to its high conductivity and low cost.43,44 Therefore, to Table S1.† The selected bond lengths and bond angles are
improve the sensing behavior of MOFs, further research into shown in Table S2.† The CCDC number for CoII-MOF is
exploiting new composites of MOFs and Acb is necessary.
In this paper, a novel CoII-MOF {[Co2(Dcpp)(Bpe)0.5 (H2O)
1581496.†
2.5 Fabrication of CoII-MOF/Acb with different Acb amounts
(μ2-H2O)]·(Bpe)0.5 n
}
(H4Dcpp
=
4,5-bis(4′-carboxylphenyl)-
First, CoII-MOF was ground into a powder. Then CoII-MOF and
Acb of different amounts (0 wt%, 0.5 wt%, 1 wt%, 2 wt%,
3 wt% and 4 wt% of CoII-MOF) were mixed into ethanol. The
homogeneous suspensions of CoII-MOF/Acb with different Acb
amounts were obtained under sonication.
phthalic acid, Bpe = 1,2-bis(4-pyridyl)ethane) was synthesized
based on the organic linkers of H4Dcpp and Bpe and used as
an electrode material for glucose sensing. Then by combining
the advantages of the CoII-MOF and Acb, a new composite of
CoII-MOF/Acb was constructed. The CoII-MOF/Acb modified
glassy carbon electrode (GCE) exhibited enhanced electro-
catalytic activity towards glucose oxidation. The sensing per-
formance of CoII-MOF/Acb/GCE with different Acb loadings
was investigated in detail. Meanwhile, the selectivity and stabi-
lity of the sensor were also explored.
2.6 Fabrication of CoII-MOF/Acb modified GCE
The glassy carbon electrode (GCE) was pre-polished to get a
mirror-like surface. The surface of the GCE was then covered
with 40 μL of the above suspension and 5 μL of Nafion
(0.05 wt%). The modified electrode was dried in air for further
measurements.
2. Experimental
2.1 Chemicals
3. Results and discussion
4,5-Bis(4′-carboxylphenyl)-phthalic acid (H4Dcpp) was obtained
from Jinan Henghua Sci. & Tec. Co., Ltd. 1,2-Bis(4-pyridyl)
ethane (Bpe) was obtained from J&K. Co(NO3)2·6H2O, glucose,
NaOH, ascorbic acid (AA), uric acid (UA) and acetaminophen
(AP) were purchased from Aladdin.
3.1 Characterization of CoII-MOF
Single-crystal X-ray diffraction analysis shows that there are
two independent CoII, one Dcpp4−, half of a coordinated Bpe,
one coordinated H2O, one μ2-OH2 and half of a free Bpe in the
asymmetric unit (Fig. 1(A)). Co1 is located in a distorted octa-
hedral coordination environment. The equatorial plane of the
octahedral coordination geometry is composed of two oxygen
atoms (O4, O7) from two Dcpp4− ligands, one oxygen atom
(O9) from a μ2-OH2 molecule and one nitrogen atom (N1) from
one Bpe ligand. The vertex of the octahedral geometry is com-
posed of two oxygen atoms (O6, O10) coming from one Dcpp4−
ligand and one coordinated H2O molecule. As opposed to Co1,
Co2 is five-coordinated via four oxygen atoms (O2, O3, O5, O8)
from three Dcpp4− ligands and one oxygen atom (O9) to form
a square pyramidal coordination environment. The bond
lengths of Co–O are in the range of 2.201–1.957 Å, which are
comparable with those of previous reports.47 As shown in
Fig. 1(B), the Dcpp4− ligand adopts the (κ1–κ1)–(κ1–κ1)–(κ1–κ1)–
(μ2)–μ6 coordination mode, which connects six CoII atoms
together in one ligand. Co1 and Co2 are bridged by two
carboxylate groups with a (κ1–κ1) mode and one μ2-OH2 mole-
cule, affording a Co2 unit with a Co1⋯Co2 distance of 3.57 Å.
As shown in Fig. 2(A), two neighboring Co2 units are linked by
four Dcpp4− ligands to produce a two-dimensional bilayer
structure. The Bpe ligand exists in two forms: one of which,
acting as a bidentate ligand, links two Co1 atoms in each 2D
layer (Fig. 2(B), right), which doesn’t expand the two-dimen-
sional layer into a three-dimensional structure; the other is
2.2 Measurements
Elemental analysis was performed using a PerkinElmer 240C
elemental analyzer. Thermogravimetric analysis (TGA) was
performed using a NETZSZH TG 209 thermal analyzer. The
morphology of CoII-MOF and CoII-MOF/Acb was characterized
using scanning electron microscopy (SEM, JSM-I100). X-ray
powder diffraction measurements (XRD, D/Max-2500 PC) were
used to analyze the purity of the sample. Electrochemical
measurements were conducted on an electrochemical work-
station (LK3200A) with a three electrode configuration contain-
ing a working electrode of a modified GCE (∅ 3 mm), a refer-
ence electrode of a saturated calomel electrode and a counter
electrode of platinum foil.
2.3 Synthesis of CoII-MOF
CoII-MOF was synthesized by mixing Co(NO3)2·6H2O
(0.1 mmol), H4Dcpp (0.05 mmol) and Bpe (0.05 mmol) with
8 mL distilled water under hydrothermal conditions at 120 °C
for three days. Purple crystals were obtained. Anal. calc. for
C34H26Co2N2O10 (%): C, 55.15; H, 3.54; N, 3.78. Found: C,
55.23; H, 3.22; N, 3.55.
2.4 Crystal structure determination of CoII-MOF
The crystallographic data for CoII-MOF were collected using a just free in the lattice, connecting each two-dimensional layer
Rigaku Saturn 724 detector at room temperature with graphite to form a three-dimensional supermolecule through hydrogen
monochromatic Mo Kα radiation (λ = 0.71073 Å). Using the bonds (Fig. 2(B), left).
SHELXL-97 crystallographic software package,45,46 the crystal
The thermal stability of CoII-MOF was studied using
structure of CoII-MOF was solved using direct methods and thermogravimetric analysis (TGA), and the results were shown
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Fig. 2 (A) A 2D layer composed of Co2 units and Dcpp4− ligands. (B)
The three-dimensional supermolecule constructed by the Co2 units,
Dcpp4− and Bpe.
Fig. 1 (A) The coordination environment of CoII. Hydrogen atoms have
been omitted for clarity. (B) The coordination mode of Dcpp4−
.
glucose. As shown in Fig. 5(A), the curves for Acb with and
without glucose completely overlap with each other, suggesting
that Acb has no catalytic activity toward glucose oxidation. In
contrast, for CoII-MOF/GCE, there are two pairs of redox peaks.
The first pair of redox peaks I/II appears at around 0.15 V, and
is attributed to the reversible transition between CoII-MOF and
CoIII(OH)-MOF. The other pair of redox peaks III/IV appears at
around 0.5 V, and could be assigned to the conversion
between CoIII(OH)-MOF and CoIV(OH)2-MOF.38 Eqn (1) and (2)
could illustrate the two reversible reactions mentioned
above:38,48
in Fig. S1.† A weight loss of 4.78% (calcd 4.86%) was observed
between 129 °C and 181 °C, which could be attributed to the
loss of coordinated H2O. Above 340 °C, CoII-MOF begins to
decompose, leading to the formation of Co2O3 as the residue
(obsd 22.52%, calcd 22.41%). The TGA results indicate a high
thermal stability of CoII-MOF.
Fig. 3(A) shows the SEM image of CoII-MOF. The CoII-MOF
shows a long strip shape, and the particle size is in the range
of 5–10 μm. After introducing Acb to the CoII-MOF, the compo-
site of CoII-MOF/Acb was used to modify the GCE. As can be
seen from Fig. 3(B), the GCE has a very smooth surface.
Fig. 3(C–H) shows the SEM image and mappings of the modi-
fied electrode, which confirm the presence and distribution of
C, N, O and Co. The elements of C, N, O and Co are evenly dis-
tributed on the surface of the electrode. The XRD patterns of
CoII-MOF and CoII-MOF/Acb are shown in Fig. 4. The peak
positions of the synthesized CoII-MOF are consistent with
those of the simulated one, indicating a pure phase of the
CoII-MOF. After mixing the Acb with the CoII-MOF, the XRD
pattern of the composite also remains unchanged.
CoII-MOF þ OHꢀ Ð CoIIIðOHÞ-MOF þ eꢀ
ð1Þ
ð2Þ
CoIIIðOHÞ-MOF þ OHꢀ Ð CoIVðOHÞ2-MOF þ eꢀ
After adding glucose, an obvious increase in the anodic
peak current was observed, especially at peak III, which indi-
cates that CoII-MOF has excellent catalytic activity towards
glucose oxidation, and the electrooxidation process is realized
by the CoIII(OH)-MOF/CoIV(OH)2-MOF rather than the CoII-
MOF/CoIII(OH)-MOF. Scheme 1 demonstrates the mechanism
for glucose oxidation. Initially, CoII-MOF is oxidized to
CoIII(OH)-MOF, and further to CoIV(OH)2-MOF. Then, the reac-
tion for the electrooxidation of glucose occurs, which is
accompanied by the consumption of CoIV(OH)2-MOF, leading
3.2 Electrochemical behavior of CoII-MOF/GCE and
CoII-MOF/Acb/GCE
The CVs of Acb/GCE, CoII-MOF/GCE and CoII-MOF/Acb/GCE to an enhanced anodic current at peak III. After introducing
were investigated in the absence and presence of 1.2 mM Acb to the CoII-MOF, there is an obvious current increase at
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Fig. 3 (A) The SEM image of CoII-MOF. (B) The SEM image of the
surface of CoII-MOF/Acb/GCE. (C–H) The SEM image and SEM mapping
of CoII-MOF/Acb/GCE.
Fig. 5 (A) CVs of Acb, CoII-MOF/GCE and CoII-MOF/Acb/GCE in the
absence and presence of 1.2 mM glucose in 0.1 mol L−1 NaOH. (B) CVs
of CoII-MOF/Acb/GCE with glucose concentrations of 0, 400, 800 and
1200 μM in 0.1 mol L−1 NaOH. Scan rate: 50 mV s−1
.
Scheme 1 The mechanism for glucose electrooxidation by CoII-MOF/
GCE.
Fig. 4 The XRD patterns of the simulated CoII-MOF, the as-synthesized
CoII-MOF and CoII-MOF/Acb.
dation can be attributed to the synergistic effect of the excel-
lent catalytic activity of CoII-MOF and the good conductivity of
Acb. On one hand, CoII-MOF contains the highly uniform and
active metal sites of CoII; on the other hand, Acb facilitates the
charge transfer and improves the contact between CoII-MOF
and the GCE.32 With increasing glucose concentration from 0
peak III in the presence of glucose when compared to that
without glucose, which could be attributed to the enhance-
ment in the conductivity of the composite. The enhanced cata-
lytic activity of the modified electrode towards glucose oxi-
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to 1.2 mM, the oxidation peak currents at peak III increase
accordingly, further indicating the electrocatalytic activity of
CoII-MOF towards glucose oxidation (Fig. 5(B)).
Fig. 6(A) show the CVs of CoII-MOF/GCE at different scan
rates from 25 to 200 mV s−1. With increasing scan rates, the
peak currents increase accordingly. As shown in Fig. 6(B), with
the increase in scan rate, the peak currents exhibit a linear
increase, suggesting
process.49
a surface-controlled electrochemical
To find the optimal potential for glucose detection,
different potentials in the range of 0.45 to 0.6 V have been
explored with successive additions of 0.1 mM glucose (Fig. 7).
Obvious current differences at each potential were observed. At
0.55 V, the response signal of the current reaches the highest
value. Therefore, the potential of 0.55 V was selected for
further measurements.
Fig. 7 The amperometric response of CoII-MOF/Acb/GCE with succes-
sive additions of 0.1 mM glucose at different potentials.
3.3 The sensing performance of CoII-MOF/Acb/GCE with
different Acb amounts
Fig. S2(A–F)† shows the chronoamperometric response curves
of CoII-MOF/Acb/GCE with 0%, 0.5%, 1%, 2%, 3% and 4% Acb
Fig. 8 (A) A comparison of the amperometric transient response with
successive additions of glucose ranging from 5–4000 μM for CoII-MOF/
GCE and CoII-MOF/Acb-2%/GCE. Inset: An enlargement of the ampero-
metric transient response with successive additions of glucose ranging
from 5–200 μM. Potential: 0.55 V. (B) A comparison of the relationship
between glucose concentration in the range of 5–4000 μM and current
signal for CoII-MOF/GCE and CoII-MOF/Acb-2%/GCE. Inset: The linear
relationship between glucose concentration and current signal for CoII-
MOF/GCE and CoII-MOF/Acb-2%/GCE. Potential: 0.55 V.
Fig. 6 (A) CVs of CoII-MOF/GCE in 0.1 mol L−1 NaOH at different scan
rates from 25 mV s−1 to 200 mV s−1. (B) Plots of peak currents vs. scan
rates.
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content with successive additions of different glucose concen-
trations ranging from 5 to 4000 μM. It could be seen that the
current increases stepwise as the glucose concentration
increases. When the Acb content is 2%, the current response
of CoII-MOF/Acb-2%/GCE reaches the highest value.
Fig. S2(G)† displays the relationship between the current
response signal and the glucose concentration with different
Acb amounts. The sensitivities increase gradually as the Acb
amounts increase from 0% to 2%. However, as the Acb
amounts further increase from 2% to 4%, the sensitivity
decreases, which may be attributed to excess Acb, which
blocks the active sites of CoII-MOF.32 Fig. 8(A) shows a com-
parison of the chronoamperometric response curves of the
modified electrodes with and without 2% Acb. The insets
show the enlarged curves with glucose concentrations ranging
from 5 to 200 μM. It can be seen that the current response of
CoII-MOF/Acb-2%/GCE is rather higher than that without Acb.
Fig. 8(B) shows a comparison of the calibration curves of the
modified electrode with and without 2% Acb. For CoII-MOF/
GCE, a good linear relationship was obtained in the concen-
Fig. 9 (A) The response curve of CoII-MOF/Acb-2%/GCE to 500 μM
glucose in the presence of 25 μM UA, AA and AP in 0.1 M NaOH.
Potential: 0.55 V. (B) Three consecutive measurements of the response
curve of CoII-MOF/Acb-2%/GCE with successive additions of glucose
ranging from 5 to 4000 μM. Potential: 0.55 V. (C) The amperometric
tration range from 60 to 700 μM with a sensitivity of 0.212 current–time curve of CoII-MOF/Acb-2%/GCE towards 1000 μM
μA μM−1 cm−2 (R2 = 0.996). For the CoII-MOF/Acb-2%/GCE, a
glucose over 3000 consecutive seconds. Potential: 0.55 V. (D) The
current percent of CoII-MOF/Acb-2%/GCE after several weeks.
good linear relationship was obtained in the concentration
range from 5 to 1000 μM, and the sensitivity is 0.255 μA μM−1
cm−2 (R2 = 0.996), with a limit of detection of 1.7 μM (S/N = 3).
Although the sensitivity of CoII-MOF/Acb-2%/GCE is slightly
improved in comparison with that of CoII-MOF/GCE, the linear
range was extended by more than ten times in the low concen-
tration range, which dramatically expands the detection range
of the sensor. Table 1 lists the sensing performance of CoII-
MOF/Acb-2%/GCE and other non-enzymatic sensors. It can be
seen that the proposed electrode is able to offer comparable or
higher sensing performance.
current changes after the subsequent addition of 25 μM UA,
25 μM AA and 25 μM AP, demonstrating a good selectivity for
glucose sensing. The good selectivity could be attributed to the
repelling effect between the negatively charged CoII-MOF and
the interferents in 0.1 M NaOH solution, which greatly reduces
the electrooxidation of these interferents on the surface of
CoII-MOF/Acb-2%/GCE at an applied potential of 0.55 V.2,50
The repeatability of the CoII-MOF/Acb-0.2%/GCE sensor was
also explored. Fig. 9(B) shows three consecutive measurements
performed with successive additions of glucose at different
concentrations ranging from 5 to 4000 μM. The relative stan-
dard deviation (RSD) is 1.6%, indicating a good repeatability
of the sensor. The current–time curve was continuously
recorded to investigate the stability of the modified electrode.
As shown in Fig. 9(C), for a long period of 3000 s, the current
signal nearly remains unchanged, which suggests a good stabi-
lity of the sensor. Long-term measurements have also been
conducted to confirm the stability of the electrode. After
storing the electrode in air for several weeks the current only
decreases by 5.2% of the initial current, as shown in Fig. 9(D),
demonstrating that the sensor has long-term stability.
3.4 Selectivity, repeatability and stability of CoII-MOF/Acb-
2%/GCE
In biological systems, uric acid (UA), ascorbic acid (AA) and
acetaminophen (AP) often co-exist with glucose, which may
affect glucose detection. With this in mind, the selectivity of
the modified electrode was investigated. Fig. 9(A) shows the
response curve of CoII-MOF/Acb-2%/GCE to glucose, UA, AA
and AP. After the addition of 500 μM glucose, an obvious
current response was observed. However, there are no obvious
Table 1 Comparison of non-enzymatic glucose sensors
Linear
range
(μM)
Modified
electrode
Sensitivity
LOD
) (μM) Ref.
(μA μM−1 cm−2
4. Conclusions
In summary, a novel CoII-MOF with a 2D bilayer structure has
been fabricated via a hydrothermal reaction. The CoII-MOF
modified electrode has good electrocatalytic activity towards
glucose oxidation. By introducing the conductive additive Acb,
a new composite of CoII-MOF/Acb was fabricated. With a 2%
addition of Acb, CoII-MOF/Acb-2%/GCE showed enhanced
Pd–Pt core–shell NCs
AuNP/NG/ITO
L2-eRuO
Cu-in-ZIF-8/SPCE
Au-CeO2
300–6800 0.170
40–16 100 0.00025
41
12
21
2.76 54
10 55
0.8 56
0.25 37
51
52
53
0–4000
0–700
0.0402
0.412
10–10 000 0.0575
Ni-MOF/Ni/NiO/C
Ni-MIL-77
4–5664
1–500
0.36745
0.001542
0.255
CoII-MOF/Acb-0.2%/GCE 5–1000
1.7 This work
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sensing performance with a high sensitivity of 0.255 μA μM−1 18 D. Aulakh, A. P. Nicoletta, J. B. Pyser, J. R. Varghese and
cm−2, a wide linear range from 5 to 1000 μM and a low detec-
M. Wriedt, Dalton Trans., 2017, 46, 6853–6869.
tion limit of 1.7 μM, as well as high selectivity and stability. 19 M. A. Ghalia and Y. Dahman, Energy Technol., 2017, 5, 356–
More importantly, this study not only provides an attractive 372.
sensing platform for glucose detection, but also opens up new 20 J. B. DeCoste, M. S. Denny, G. W. Peterson, J. J. Mahle and
opportunities for MOFs as highly effective electrochemical
sensing platforms.
S. M. Cohen, Chem. Sci., 2016, 7, 2711–2716.
21 C. Yu, Z. Shao and H. Hou, Chem. Sci., 2017, 8, 7611–7619.
22 H. Kaur, M. Venkateswarulu, S. Kumar, V. Krishnan and
R. R. Koner, Dalton Trans., 2018, 47, 1488–1497.
23 S. M. J. Rogge, A. Bavykina, J. Hajek, H. Garcia, A. I. Olivos-
Suarez, A. Sepúlveda-Escribano, A. Vimont, G. Clet,
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F. X. L. Xamena, V. V. Speybroeck and J. Gascon, Chem. Soc.
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24 H. Li, Y. Han, Z. Shao, N. Li, C. Huang and H. Hou, Dalton
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25 R. W. Huang, Y. S. Wei, X. Y. Dong, X. H. Wu, C. X. Du,
S. Q. Zang and T. C. W. Mak, Nat. Chem., 2017, 9,
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Conflicts of interest
There are no conflicts to declare.
Acknowledgements
This work was supported by the Natural Science Foundation of
Hebei Province (B2016209266) and the Department of Science
and Technology of Tangshan of China (15130201C).
26 Y. Han, N. F. Chilton, M. Li, C. Huang, H. Xu, H. Hou,
B. Moubaraki, S. K. Langley, S. R. Batten, Y. Fan and
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