摘要
为了高效检测牛奶中H_(2)O_(2)含量,该研究提出了一种基于ZnFeCoO_(4)催化还原H_(2)O_(2)的非酶电化学传感器。首先,通过溶胶-凝胶燃烧法合成ZnCo_(2)O_(4),再利用Fe部分取代Co合成ZnFeCoO_(4)。采用透射电子显微镜、X射线衍射及X射线光电子能谱对催化剂的晶体结构和形貌进行表征,并采用循环伏安法对该电极的电化学性能进行研究。结果表明:ZnFeCoO_(4)具有较好的晶型,基于ZnFeCoO_(4)的电化学传感器对H_(2)O_(2)有良好的电催化性能,检测限为0.5μmol/L;过氧化氢浓度在0.5~2.5 mmol/L范围内与还原峰电流呈线性关系,决定系数为0.989。此外,传感器对H_(2)O_(2)具有优异重现性和选择性。在实际牛奶样品的加标试验中回收率达到98.60%~101.23%。研究可为液态食品中检测H_(2)O_(2)提供重要的应用参考。
The objective of this study was to develop an efficient non-enzymatic electrochemical sensor for H_(2)O_(2)detection in milk using the catalytic reduction of H_(2)O_(2)on ZnFeCoO_(4).Firstly,ZnFeCoO_(4)derived from ZnCo_(2)O_(4)by the partial substitution of Co with Fe was synthesized via sol-gel combustion.In ZnCo_(2)O_(4),1 mmol Zn(NO3)2·6H2O and 2 mmol of Co(NO3)2·6H2O were dissolved in a nitric acid solution(2 mL of nitric acid,and 30ml of distilled water).The sticky gel was subsequently obtained by adding 15 mmol citric acid and stirring for 5 h in the oil bath at 90℃.After that,the gel was placed in a 170℃oven(10℃/min heating rate)for 12 h.Then,the moisture-removed gel was crushed with a mortar.Finally,the powder was calcined in a 600℃tubular furnace(5℃/min heating rate)for 6 hours to obtain the spinel phase ZnCo_(2)O_(4)powder.The preparation process of ZnFeCoO_(4)was consistent with that of ZnCo_(2)O_(4).The only difference was that the 2 mmol of Co(NO3)2·6H2O was replaced with 2 mmol of Fe(NO3)2·6H2O.Transmission electron microscopy,X-ray diffraction,and X-ray photoelectron spectroscopy were used to characterize the crystal structure and morphology of the catalyst,while cyclic voltammetry(CV)was used to study the electrochemical performance of the electrode.In order to verify the effectiveness of the ZnFeCoO_(4)electrode in detecting H_(2)O_(2)content in milk,the milk from the local supermarket was centrifuged and 1 mL supernatant was dissolved in 10 mL PBS(pH value 7.4).Standard addition was used for the recovery experiment.The results showed that a similar morphology was obtained after the partial or complete replacement of Co with Fe.ZnFeCoO_(4)presented a better crystal shape and high consistency with the standard database card JCPDS No.23-1390.The mass ratios of Zn,Co,and Fe were measured as 31.46%,35.77%,and 27.15%,respectively,and the molar ratio was about 1:1.2:1,which roughly met the chemical expression of the compound.The XRD patterns of ZnCo_(2)O_(4)and ZnFeCoO_(4)showed that the diffraction peaks of ZnFeCoO_(4)were basically the same as those of ZnCo_(2)O_(4),both of which were conformed to the standard database card JCPDS No.23-1390,indicating the spinel phases.In addition,the diffraction peak of ZnFeCoO_(4)was shifted to a smaller angle than that of ZnCo_(2)O_(4),because the lattice radius of Fe3+was slightly larger than that of Co3+.This proved the successful synthesis of spinel phase ZnFeCoO_(4).The CV analysis showed that the ZnFeCoO_(4)presented better catalytic activity than the ZnCo_(2)O_(4),where the electrochemical sensor using ZnFeCoO_(4)shared the better electrocatalytic performance for H_(2)O_(2)with a theoretical detection limit of 0.5μmol/L.There was a linear relationship between the concentration of hydrogen peroxide and the peak reduction current in the range of 0.5-2.5 mmol/L,where the determination coefficient(R2)is 0.989.The stability and selectivity of ZnFeCoO_(4)electrode analysis showed that there was no significant change in the current density when the electrode was exposed to 1 mmol/L H_(2)O_(2)solution for 30 days.After one month,the observed current density was about 92.7%of the original current density,with a relative standard deviation of 13.2%,indicating the better stability of the ZnFeCoO_(4)electrode.The amperage method was implemented to evaluate the effect of ascorbic acid,glucose,sucrose,citric acid,urea,and H_(2)O_(2)on the current density response.Except for H_(2)O_(2),there was no significant change in the current density,indicating the better selectivity of the sensor.In addition,the sensor also presented excellent reproducibility for H_(2)O_(2).Excellent recoveries from 98.60%to 101.23%were obtained for the H_(2)O_(2)-spiked milk.The as-presented sensor can be expected to serve as a promising candidate for the H_(2)O_(2)determination in food safety.
作者
马懿
陈晓姣
刘自山
伍辉祥
MA Yi;CHEN Xiaojiao;LIU Zishan;WU Huixiang(College of Biological Engineering,Sichuan University of Science and Engineering,Yibin 644005,China;Guangdong Institute of Product Quality Supervision and Inspection Light Industry Textile Garment Testing Department,Guangzhou 510670,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2023年第3期260-264,共5页
Transactions of the Chinese Society of Agricultural Engineering
基金
四川省自然基金项目(2020YJ0402)
2020年五粮液股份公司-四川轻化工大学产学研合作项目(CXY2020ZR004)。
