The development of a new electrochemical sensor based on ${Cu}_{2} O @ C$ core-shell and polyalizarin/nafion polymers for determination of bisphenol A at two area potentials
基于0#核壳型聚茜素/Nafion聚合物的双酚A电化学传感器的研制

Nader Amini $^{*}$ , Afshin Maleki, Reza Rezaee, Ebrahim Mohammadi, Mahdi Safari, Behzad Shahmoradi, Hiua Daraie
Nader Amini $^{*}$ ，Afshin Maleki，Reza Rezaee，Ebrahim Mohammadi，Mahdi Safari，Behzad Shahmoradi，Hiua Daraie

Environmental Health Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
环境卫生研究中心，健康发展研究所，库尔德斯坦医科大学，伊朗萨南达杰

ARTICLE INFO 文章信息

Keywords: 保留字：

Bisphenol A 双酚A

{Cu}_{2} O @ C

core-shell

{Cu}_{2} O @ C

核壳
Polyalizarin, Electrooxidation, Sensor
聚茜素，电氧化，传感器

Abstract 摘要

In this paper, employing a hydrothermal method, we synthesized ${Cu}_{2} O$ nanoparticles and ${Cu}_{2} O @ C$ core-shell. The scanning electron microscope (SEM), X -Ray diffraction (XRD), dynamic light scattering (DLS) and zeta potential techniques were used for characterized of the ${Cu}_{2} O$ nanoparticles and ${Cu}_{2} O @ C$ core-shell. The zeta potential values were obtained to be -11.16 mV and -0.88 mV for ${Cu}_{2} O$ and ${Cu}_{2} O @ C$ , respectively. The average hydrodynamic size of diameter for ${Cu}_{2} O$ and ${Cu}_{2} O @ C$ was obtained as $48 - 62 nm$ and 200-250 nm by DLS method. Polyalizarin yellowe R (PAYR) and Nafion (Nf) conductive polymers with ${Cu}_{2} O @ C$ core-shell immobilizing on glassy carbon electrode (PAYR/Cu2O@C /Nf/GCE), they were applyed for fabrication of an original electrochemical sensor to detect and determine bisphenol A. Cyclic voltammetry (CV) and impedimetric techniques were employed to confirm the proposed sensor construction. Furthermore, the electrocatalytic-based oxidation behavior which electrode showed was studyed by cyclic voltammetry and differential puls voltammetry (DPV) methods. The results showed that, PAYR/ ${Cu}_{2} O @ C / Nf$ composite has a great electrocatalytic features for detecting and determining bisphenol A at $0.12 V (OX 1)$ and 0.63 V (OX2). For OX1 peak, linear range ( $1 -$ $1400 μ M$ ), limit of detection ( 260 nM ) and sensitivity ( $0.0009 μ A / μ M$ ) were obtained. Moreover, considering the peak of OX2, linear range $(1 - 1400 μ M)$ , limit of detection ( 240 nM ) and sensitivity $(0.0009 μ A / μ M)$ were calculated. PAYR/ ${Cu}_{2} O @ C / Nf / GCE$ presented considerable advantages for instance high sensitivity, used for real samples, simple preparation, low detection of limit, and specially the oxidation of bisphenol A at two applied potentials that it reported for the first time.
本文采用水热法合成了 ${Cu}_{2} O$ 纳米粒子和 ${Cu}_{2} O @ C$ 核壳结构。采用扫描电子显微镜（SEM）、X射线衍射（XRD）、动态光散射（DLS）和zeta电位等技术对2#纳米粒子和3#核壳结构进行表征。获得的zeta电位值对于 ${Cu}_{2} O$ 和 ${Cu}_{2} O @ C$ 分别为-11.16mV和-0.88mV。通过DLS方法获得 ${Cu}_{2} O$ 和 ${Cu}_{2} O @ C$ 的平均流体动力学直径尺寸为 $48 - 62 nm$ 和200-250 nm。将聚茜素黄R（PAYR）和Nafion（Nf）核壳型导电聚合物固定于玻碳电极（PAYR/Cu2O@C /Nf/GCE）上，制备了检测双酚A的电化学传感器。循环伏安法（CV）和阻抗技术，以确认所提出的传感器结构。采用循环伏安法和微分普尔斯伏安法（DPV）研究了该电极的电催化氧化行为。结果表明，PAYR/ ${Cu}_{2} O @ C / Nf$ 复合材料在 $0.12 V (OX 1)$ 和0.63 V（OX 2）下对双酚A具有良好的电催化性能。对于OX 1峰，获得了线性范围（ $1 -$ $1400 μ M$ ）、检测限（260 nM）和灵敏度（ $0.0009 μ A / μ M$ ）。此外，考虑到OX 2的峰，计算线性范围 $(1 - 1400 μ M)$ 、检测限（240 nM）和灵敏度 $(0.0009 μ A / μ M)$ 。PAYR/ ${Cu}_{2} O @ C / Nf / GCE$ 具有灵敏度高、适用于真实的样品、制备简单、检出限低等优点，特别是首次报道了双酚A在两种外加电位下的氧化。

1. Introduction 1.介绍

Bisphenol A is a precursor for synthesize polycarbonate, epoxy resin, used in industry, medical materials and other compounds in food packaging. [1]. It was considered to be a typical increasing the incidence of cancer, impaired brain development, behavior, endocrine disruptor in the environment and interfering with the human endocrine system, sexual differentiation, lowering reproduction and the immune function [1-2]. Bisphenol A is resistant to degradation by chemical methods and it has been widly studied in lots of environmental samples [3]. For example, the attendance of bisphenol A in wastewater samples has been determined in significant amounts ranging from 0.07 to

150 μ g L^{- 1}

and 0.013 to

0.24 μ g g^{- 1}

in primary and secondary wastewater sludge [4]. Furthermore, it has been obtained frequently in natural waters samples
双酚A是合成聚碳酸酯、环氧树脂的前体，用于工业、医疗材料和食品包装中的其他化合物。[1]的文件。它被认为是一种典型的增加癌症发病率，损害大脑发育，行为，环境中的内分泌干扰物，干扰人体内分泌系统，性别分化，降低生殖和免疫功能[1-2]。双酚A不易被化学方法降解，已在大量环境样品中广泛研究[3]。例如，在一级和二级废水污泥中，已确定废水样品中双酚A的存在量为0.07至

150 μ g L^{- 1}

和0.013至

0.24 μ g g^{- 1}

[4]。此外，在天然沃茨样品中也经常能得到这种物质
that related to the movement of BPA-based products (for example 568

ng / L

of bisphenol A in bottled water) and through effluent of wastewater [5]. In order to avoiding the probable side effects of bisphenol A to kids, European Union, China, most states of Canada and America impose restrictive on used of milk bottles containing bisphenol A [6]. The oral reference dose (RfD) for bisphenol A presented by United States Environmental Protection Agency (EPA) is

50 μ g / kg

body weight day [3]. Thus, the employment of simple and a sensitive technique for bisphenol A detection is essential for human health and safety and interest to evaluate the endocrine activity of effluent discharged into the environment [2]. Up to now, some analytical techniques, have been presented for bisphenol A detection such as gas chromatography-mass spectrometry (GC-Mass) [7], high performance liquid chromatography (HPLC) coupled to ultra violet (UV) [8-9], fluorescence [10], gas
与BPA产品（例如瓶装水中的568

ng / L

双酚A）的移动有关，并通过废水的流出物[5]。为了避免双酚A对儿童可能产生的副作用，欧盟、中国、加拿大大部分州和美国都对含双酚A奶瓶的使用进行了限制[6]。美国环境保护署（EPA）提出的双酚A口服参考剂量（RfD）为

50 μ g / kg

体重日[3]。因此，采用简单而灵敏的双酚A检测技术对人类健康和安全以及评估排放到环境中的废水的内分泌活性至关重要[2]。到目前为止，已经提出了一些用于双酚A检测的分析技术，例如气相色谱-质谱（GC-Mass）[7]、与紫外（UV）偶联的高效液相色谱（HPLC）[8 - 9]、荧光[10]、气相色谱-质谱（GC-MS）[7]、气相色谱-质谱（HPLC）[8-9]、气相色谱-质谱（GC-MS）[8-9]、气相色谱-质谱（GC-MS）[8-9]、气相色谱-质谱（GC-MS）[8 - 9]和气相色谱-质谱（GC-MS）[8 - 9]。

chromatography(GC) [11] and electrochemical methods [12,13]
色谱法（GC）[11]和电化学方法[12，13]
But then, the simple and low costs techniques with minimal sample pretreatment are requried for the detection of BPA. Electrochemical methods can be used as the interesting techniques for the detection and determination of BPA. The electrochemical determination of BPA at the surface of bare electrodes is a very slow process. To solve this problem, the surface of the bare electrodes is modified with various compounds such as some polymeric materials [14], metals [15] and nanoparticles especially have been used.Alizarin yellow

R

polymer is an organic dye and a conductive polymer with a structure of salicylic acid used to modification of electrode and used as a conductive polymer for fabrication of electrochemical sensors. Advantages of conductive polymers are stability, reproducibility, homogeneity in chemical deposition and strong adhesion to the electrode surface, which have highlighted their role and application in electrochemical sensor modification [16].
但是，BPA的检测需要简单、低成本、样品预处理量少的技术。电化学方法是检测和测定双酚A的有效方法。双酚A在裸电极表面的电化学测定是一个非常缓慢的过程。为了解决这个问题，裸电极的表面用各种化合物修饰，例如一些聚合物材料[14]，金属[15]和纳米颗粒，特别是已经使用的。茜素黄

R

聚合物是一种有机染料和具有水杨酸结构的导电聚合物，用于修饰电极，并用作制造电化学传感器的导电聚合物。导电聚合物的优点是稳定性、重现性、化学沉积的均匀性和对电极表面的强粘附性，这突出了它们在电化学传感器修饰中的作用和应用[16]。

The core-shell particles are the attractive materials for its increased properties from core to shell components (controlled by sizes and shapes), their synergy and widly range of applications in construction of electrochemical biosensors and sensors [17-18]. Currently, the core-shell with containing carbon element, has interesting for many researchers due to its chemical activity, low cost, biocompatibility and simple synthesis [19-20]. A shell layer of carbon element can enhance the core particle stability with a subsequent promotion in, biocompatibility, catalytic properties and non-toxicity [21-23]. Some metal nanoparticles, for examples,

Au, Ag

and Cu nanoparticles are used in electrochemical sensors preparation. Among nanoparticles, for their non-toxic, good catalytic properties and low cost, copper NPs have been investigated widly [24]. For construction of electrochemical sensing, core-shell materials such as

Au @ Ag, Ag @ {SiO}_{2}, Ag @ C

are used [25-27].
核-壳颗粒是有吸引力的材料，因为其从核到壳组分的性能增加（由尺寸和形状控制），它们的协同作用和在构建电化学生物传感器和传感器中的广泛应用[17-18]。目前，含有碳元素的核-壳由于其化学活性、低成本、生物相容性和合成简单而引起许多研究人员的兴趣[19-20]。碳元素的壳层可以增强核心颗粒的稳定性，随后促进生物相容性、催化性能和无毒性[21-23]。一些金属纳米颗粒，例如

Au, Ag

和Cu纳米颗粒用于电化学传感器的制备。在纳米颗粒中，由于其无毒、良好的催化性能和低成本，铜纳米颗粒已被广泛研究[24]。对于电化学传感的构造，使用诸如

Au @ Ag, Ag @ {SiO}_{2}, Ag @ C

的核-壳材料[25-27]。

Previous reportes showed that there was not any research based on the electrocatalytic effects of

{Cu}_{2} O @ C /

nafion and polyalizarin yellow R

({Cu}_{2} O @ C / Nf / PAYR)

in order to electrooxidation of bisphenol A at two applied potentials. We immobilized (

{Cu}_{2} O @ C / Nf / PAYR)

on the surface of glassy carbon electrod for determination of bisphenol A.
以往的研究表明，没有任何研究基于

{Cu}_{2} O @ C /

nafion和聚茜素黄R

({Cu}_{2} O @ C / Nf / PAYR)

的电催化作用，以双酚A在两个外加电位下的电氧化。本文研究了将（2#）固定在玻碳电极表面测定双酚A的方法。
electrode was placed in a 20 mL electrochemical cell. A Metrohm pHmeter was used to adjusthing of pH values.
将电极置于20 mL电化学电池中。使用Metrohm pH计调节pH值。

2.3. Synthesis of ${Cu}_{2} O @ C$ particles
2.3. ${Cu}_{2} O @ C$ 颗粒的合成

{Cu}_{2} O @ C

core-shell was synthesized by a hydrothermal method. Aqueous solution of 25 ml copper sulfate ( 0.1 M ), 50 ml sodium hydroxide ( 1 M ), 5 ml glucose solution ( 1 M ) and 0.01 g cetyltrimethylammonium bromide was transferred into 100 ml reactor and put into an oven under

80^{\circ} C

for 8 hours. After cooling to room temperature, the precipitation was centrifuged with 2000 rpm , washed with DI water and ethanol mixture, and dried at

70^{\circ} C

for 12 hours. In order to comparison,

{Cu}_{2} O

nanoparticle was synthesized by a similar method without using cetyltrimethylammonium bromide under

90^{\circ} C

for 2 hours.
通过水热法合成了

{Cu}_{2} O @ C

核-壳。将25 ml硫酸铜（0.1 M）、50 ml氢氧化钠（1 M）、5 ml葡萄糖溶液（1 M）和0.01 g十六烷基三甲基溴化铵的水溶液转移到100 ml反应器中，并放入

80^{\circ} C

烘箱中8小时。冷却至室温后，将沉淀以2000 rpm离心，用DI水和乙醇混合物洗涤，并在

70^{\circ} C

下干燥12小时。为了比较，通过类似的方法合成

{Cu}_{2} O

纳米颗粒，而不使用十六烷基三甲基溴化铵，在

90^{\circ} C

下持续2小时。

2.4. Electrode preparation and modification
2.4.电极制备和修饰

Before modifying, in order to remove contaminants on the surface electrode, the bare glassy carbon electrode was first polished with alumina paste of different grades. The second step, this electrode was ultrasonicated in ethanol and DI water mixture for 120 seconds to remove the adsorbed particles. The third step,

2 μ L

{Cu}_{2} O @ C /

nafion solution was deposited on the electrode surface (nafion was used to stabilize the

{Cu}_{2} O @ C

core-shell) and then drying at room temperature. The fourth step, at the range of potential -1.0 to 1.2 V and at

pH = 7

the electropolymerization of alizarin yellow

R (1 mM)

was recorded at scan rate

100 mV / s

{Cu}_{2} O @ C /

nafion /GCE (Fig. 1A).
在修饰前，为了去除电极表面的污染物，首先用不同等级的氧化铝浆料对裸玻碳电极进行抛光。第二步，将该电极在乙醇和DI水混合物中超声处理120秒以去除吸附的颗粒。第三步，将

2 μ L

1#nafion溶液沉积在电极表面上（nafion用于稳定

{Cu}_{2} O @ C

核-壳），然后在室温下干燥。第四步，在-1.0至1.2 V的电位范围和

pH = 7

下，在

{Cu}_{2} O @ C /

nafion /GCE上以

100 mV / s

扫描速率记录茜素黄

R (1 mM)

的电聚合（图1A）。

As can be seen, with continuous scanning number (15 cycles), reduction and oxidation peak currents were increased and shows that the successive growth of the PAYR on the

{Cu}_{2} O @ C /

nafion /GCE. The mechanism of polymerization of alizarin is proposed as follows:
可以看出，随着连续扫描次数（15次循环），还原和氧化峰电流增加，并显示PAYR在

{Cu}_{2} O @ C /

nafion /GCE上连续生长。茜素的聚合反应机理如下：

2. Experimental 2.实验

2.1. Reagents and materials
2.1.试剂和材料

Buffer solutions were prepared from

{Na}_{3} {PO}_{4}, {Na}_{2} {HPO}_{4}, {NaH}_{2} {PO}_{4}

HCl, H_{3} {PO}_{4}, NaOH

and for other applications cetyltrimethylammonium bromide (CTAB), nafion, alizarin yellow R, glucose,

{CuSO}_{4} \cdot 5 H_{2} O

and bisphenol A are used. All of materials were purchased from Merck company.
缓冲溶液由

{Na}_{3} {PO}_{4}, {Na}_{2} {HPO}_{4}, {NaH}_{2} {PO}_{4}

、

HCl, H_{3} {PO}_{4}, NaOH

制备，对于其它应用，使用十六烷基三甲基溴化铵（CTAB）、全氟磺酸、茜素黄R、葡萄糖、

{CuSO}_{4} \cdot 5 H_{2} O

和双酚A。所有材料均购自Merck公司。

2.2. Apparatus 2.2.装置

μ

-Autolab (Eco Chemie U/techt, the Netherlands) was applied for electrochemical tests. A three-electrode system, consisting of a platinum wire counter electrode ( 0.2 mm diameter), a glassy carbon working electrode (GCE) and an

Ag (s) / AgCl (s) / {Cl}^{-}

(aq, saturated KCl ) reference
使用

μ

-Autolab（Eco Chemie U/techt，荷兰）进行电化学测试。三电极系统，由铂丝对电极（直径0.2 mm）、玻碳工作电极（GCE）和

Ag (s) / AgCl (s) / {Cl}^{-}

（饱和KCl水溶液）参比组成

3. Results and discussion
3.结果和讨论

3.1. Characterization of ${Cu}_{2} O$ nanoparticles and ${Cu}_{2} O @ C$ core-shell particles
3.1. ${Cu}_{2} O$ 纳米颗粒和 ${Cu}_{2} O @ C$ 核壳颗粒的表征

The scanning electron microscopic (SEM) images for

{Cu}_{2} O

nanoparticles and

{Cu}_{2} O @ C

coreshell particles were presented in Figs of 1B and 1 C , respectively. As can be seen, the morphologies

{Cu}_{2} O

and

{Cu}_{2} O @ C

are not similar and copper oxide and carbon were obtained as a core and shell. Also, XRD patterns were investigated for

{Cu}_{2} O

nanoparticles and

{Cu}_{2} O @ C

coreshell. Fig. 1D shows that the two patterns exhibit similar diffraction peaks. No new peaks for carbon observed in the pattern of

{Cu}_{2} O @ C

. Probably, carbon is amorphous, not crystalline. Furthermore, to get more data about the details of

{Cu}_{2} O

and

{Cu}_{2} O @ C

, other analysis methods were applied. Zeta potential shows the stability and charge of colloidal dispersions. Zeta potentials was calculated for
0#纳米颗粒和1#核壳颗粒的扫描电子显微镜（SEM）图像分别示于图1B和1C中。可以看出，形态

{Cu}_{2} O

和

{Cu}_{2} O @ C

不相似，并且获得氧化铜和碳作为核和壳。此外，研究了

{Cu}_{2} O

纳米颗粒和

{Cu}_{2} O @ C

芯壳的XRD图案。图1D示出了两个图案表现出相似的衍射峰。在

{Cu}_{2} O @ C

的图案中没有观察到新的碳峰。很可能，碳是无定形的，而不是晶体。此外，为了获得更多关于

{Cu}_{2} O

和

{Cu}_{2} O @ C

的细节的数据，应用了其他分析方法。Zeta电位显示胶体分散体的稳定性和电荷。计算Zeta电位，

Fig. 1. (A) The successive cyclic voltammorams of the electropolymerization of PAYR on

{Cu}_{2} O @ C / Nf / GCE

at potential scan rate

100 {mVs}^{- 1}

.(B) SEM images of

{Cu}_{2} O

{Cu}_{2} O @ C

coreshell . (D) XRD patterns for

{Cu}_{2} O

nanoparticles and

{Cu}_{2} O @ C

coreshell.
图1. (A)用循环伏安法测定了PAYR在0#电极上以1#电位扫描速率电聚合的连续循环伏安曲线。(B)

{Cu}_{2} O

纳米颗粒和

{Cu}_{2} O @ C

芯壳的SEM图像。(D)

{Cu}_{2} O

纳米颗粒和

{Cu}_{2} O @ C

芯壳的XRD图案。

Fig. 2. Zeta potential graphs of (A)

{Cu}_{2} O

nanoparticles (B)

{Cu}_{2} O @ C

coreshell
图二.（A）

{Cu}_{2} O

纳米颗粒（B）

{Cu}_{2} O @ C

核壳的Zeta电位图

Fig. 3. The DLS graphs of (A)

{Cu}_{2} O

nanoparticles (B)

{Cu}_{2} O @ C

coreshell
图3.（A）

{Cu}_{2} O

纳米颗粒（B）

{Cu}_{2} O @ C

核壳的DLS图

- Corresponding author: 通讯作者：
E-mail address: naderamini95@yahoo.com (N. Amini).
电子邮件地址：naderamini95@yahoo.com（N. Amini）。

ARTICLE INFO 文章信息

Keywords: 保留字：

Abstract 摘要

1. Introduction 1.介绍

2.3. Synthesis of Cu 2 O @ C Cu 2 O @ C Cu_(2)O@C\mathrm{Cu}_{2} \mathrm{O} @ C particles2.3. Cu 2 O @ C Cu 2 O @ C Cu_(2)O@C\mathrm{Cu}_{2} \mathrm{O} @ C 颗粒的合成

2.4. Electrode preparation and modification2.4.电极制备和修饰

2. Experimental 2.实验

2.1. Reagents and materials2.1.试剂和材料

2.2. Apparatus 2.2.装置

3. Results and discussion3.结果和讨论

2.3. Synthesis of ${Cu}_{2} O @ C$ particles
2.3. ${Cu}_{2} O @ C$ 颗粒的合成

2.4. Electrode preparation and modification
2.4.电极制备和修饰

2.1. Reagents and materials
2.1.试剂和材料

3. Results and discussion
3.结果和讨论