Electrochemical Analysis Of Methyl Parathion And Heavy Metal Ions Based On Several Novel Nanomaterials Modified Electrodes

With the development of industry,the environmental problems are becoming more and more serious.Methyl parathion(MP),a kind of broad-spectrum and highly effective organophosphorus insecticide,has been used for decades.Because of the high toxicity of MP,its extensive use has caused serious harm to the environment and human health.Meanwhile,heavy metal ions(HMIs)also cause serious harm to the environment and human health.HMIs are difficult to be biodegradable,and it can accumulate in the organism,causing poisoning in the human body.Therefore,it is very important to detect them.Electrochemical sensor is an important analytical method with the advantages of simple structure,low cost and high sensitivity.It is often used in the fields of environmental analysis.The core of building an electrochemical sensor is excellent electrode modification materials.Carbon nanomaterials have been widely used in sensing analysis due to excellent physical and chemical properties,low cost and easy availability.MXenes,a kind of two-dimensional transition metal carbide/nitride material,has excellent inherent characteristics,such as high conductivity,high specific surface area and high porosity.These make it have important application prospects in electrochemical(bio)sensors.In this paper,several electrochemical sensors based on functionalized nanocomposites were constructed,and electrochemical analysis of environmental pollutants methyl parathion(MP)and toxic heavy metal ions(HMI_S)were carried out.The main contents of this paper are as follows:(1)We have successfully prepared a core–shell multiwalled carbon nanotubes@graphene oxide nanoribbons(MWCNTs@GONRs)heterostructure with enhanced electrochemical performance through a facile wet chemical method.And a highly sensitive electrochemical sensor was constructed for the detection of methyl parathion(MP)based on the nanocomposite.The nanocomposite was characterized by scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy,Raman spectroscopy,electrochemical and impedance spectroscopies.The application of MWCNTs@GONRs nanocomposite for determination of MP was investigated by cyclic voltammetry and differential pulse voltammetry.The MWCNTs@GONRs nanocomposite modified glassy carbonelectrode(GCE)reveals excellent electrochemical catalytic activities toward MP with a low limit of detection(0.0043?M)and a wide linear range(0.01-25.0?M).(2)A proof-of-principle concept for ASV sensing HIMs without electrodeposition was proposed by using Ti₃C₂T_x MXene/carbon black(Ti₃C₂T_x@CB)nanohybrids as electrode materials.In this proposal,Ti₃C₂T_x MXene can enable HIMs to be immobilized and self-reduce directly on Ti₃C₂T_x@CB electrode surface resulted from the high adsorption and reduction capability of Ti₃C₂T_x towards HIMs;meanwhile,CB was introduced to prevent Ti₃C₂T_x Mxene aggregation and improve the related electron transfer.Selecting Cu²⁺as analyte,after optimizing various conditions,a low limit of detection(0.0046?M)coupled with a wide linear range(0.01-15.0?M)for Cu²⁺were achieved successfully based on the proposed proposal.(3)Based on the above research and analysis method for HMIS without electrodeposition,we introduced Ti₃C₂T_x MXene nanoribbons(Ti₃C₂T_x NR),a kind of MXenes nanomaterial derived from nanosheets as the sensing element.Ti₃C₂T_x NR has higher specific surface area,more exposed active sites and more hydroxyl functional groups,so it has higher adsorption and reduction ability to HMIS,which further improves the sensitivity and sensing performance of HMIs detection.Selecting Cd(II)(Cd²⁺)as analyte,the work demonstrated that Ti₃C₂T_x NR modified electrode can be successfully applied for detection of Cd²⁺,with high sensitivity and exhibits low detection limit of 0.94 n M.