A Sensitive Electrochemical Sensor Based on Ion Imprinted Polymers with Gold Nanoparticles for High Selective Detecting Cd (II) Ions in Real Samples

Electroactive poly(thionine) as imprinted polymer and reference probe simultaneously for ratiometric ion imprinted electrochemical Pb2+sensor

In this work, an electrochemical sensor based on ion-imprinted polymer/Au nanoparticles/porous biochar (IIP/AuNPs/PBC) composite was proposed for the highly selective and sensitive detection of Pb2+. In this work, poly (thionine) (pTHI) served simultaneously as imprinted polymer and reference probe. It could not only realize the specific detection of Pb2+, but also provide an internal reference signal to eliminate the influence of human and environmental factors on the detection signal and further improve the stability of the sensor. In addition, the AuNPs/PBC composite with large specific surface area, excellent electron transport and electrocatalytic performance could effectively enhance the detection signal as a carrier material. At the same time, the AuNPs on the PBC surface would promote the formation of uniform and stable IIP through Au-S bonds. The synergistic effect between IIP, AuNPs/PBC and ratiometric signal mode gave the Pb2+sensor excellent performance, including a wide linear range (0.1-1000μg l-1), low detection limit (0.03μg l-1, S/N = 3), excellent selectivity and stability. All these results indicate that the proposed sensor could provide a meaningful reference for highly selective detection of heavy metal ions (HMIs).

Nanomaterials-Based Ion-Imprinted Electrochemical Sensors for Heavy Metal Ions Detection: A Review

Heavy metal ions (HMIs) pose a serious threat to the environment and human body because they are toxic and non-biodegradable and widely exist in environmental ecosystems. It is necessary to develop a rapid, sensitive and convenient method for HMIs detection to provide a strong guarantee for ecology and human health. Ion-imprinted electrochemical sensors (IIECSs) based on nanomaterials have been regarded as an excellent technology because of the good selectivity, the advantages of fast detection speed, low cost, and portability. Electrode surfaces modified with nanomaterials can obtain excellent nano-effects, such as size effect, macroscopic quantum tunneling effect and surface effect, which greatly improve its surface area and conductivity, so as to improve the detection sensitivity and reduce the detection limit of the sensor. Hence, the present review focused on the fundamentals and the synthetic strategies of ion-imprinted polymers (IIPs) and IIECSs for HMIs detection, as well as the applications of various nanomaterials as modifiers and sensitizers in the construction of HMIIECSs and the influence on the sensing performance of the fabricated sensors. Finally, the potential challenges and outlook on the future development of the HMIIECSs technology were also highlighted. By means of the points presented in this review, we hope to provide some help in further developing the preparation methods of high-performance HMIIECSs and expanding their potential applications.

Highly selective electrochemical sensing based on electropolymerized ion imprinted polyaniline (IIPANI) on a bismuth modified carbon paste electrode (CPE-Bi) for monitoring Nickel(ii) in river water

Electrochemical sensors based on ion-imprinting polymers have emerged as an effective analytical tool for heavy metal tracking. This study describes a simple and facile technique for manufacturing a highly selective and sensitive electrode using an ion imprinting polymer on a bismuth-modified carbon paste electrode. The developed sensor applied aniline as a functional monomer and was used for tracking Ni(ii) ions. The proposed sensor was thoroughly characterized by scanning electron microscopy, cyclic voltammetry, and differential pulse striping anodic voltammetry. The analytical evaluation showed that the proposed sensor has a linear dynamic range (R 2 = 0.999) for the Ni(ii) concentration range of 0.01 to 1 μM and a limit of detection value of 0.00482 μM. The proposed sensor showed excellent performance when tested for tracking Ni(ii) ions in the presence of interfering ions (Cd(ii), Co(ii), Cu(ii), and Zn(ii) ions) at a 1000-fold higher concentration. When the proposed sensor was tested for tracking Ni(ii) concentration in an actual river sample, our modified sensor showed similar results compared to the atomic absorption spectroscopy evaluation (p > 0.05, n = 3). In summary, our proposed sensor is promising for monitoring Ni(ii) ions in the aquatic environment.

Influence of Synthesis Parameters and Polymerization Methods on the Selective and Adsorptive Performance of Bio-Inspired Ion Imprinted Polymers

Ion-imprinted polymers (IIPs) have been widely used in different fields of Analytical Sciences due to their intrinsic selective properties. However, the success of chemical imprinting in terms of selectivity, as well as the stability, specific surface area, and absence of swelling effect depends on fully understanding the preparation process. Therefore, the proposal of this review is to describe the influence of relevant parameters on the production processes of ion-imprinted polymers, including the nature (organic, inorganic, or hybrid materials), structure, properties of the salt (source of the metal ion), ligand, crosslinking agent, porogenic solvent, and initiator. Additionally, different polymerization methods are discussed, the classification of IIPs as well as the applications of these adsorbent materials in the last years (2017–2022).

Preparation, Characterization of Cd(II) Ion-Imprinted Microsphere and Its Selectivity for Template Ion

Cadmium is one of the many toxic elements for humans even at low concentrations, and it could exist in the environment for a long time. The ion imprinting technique has gained much attention due to its selective recognition performance. In this study, a cadmium ion imprinted maleic acid-co-acrylonitrile polymeric microsphere (Cd-I-MA-co-AN) was synthesized via precipitation polymerization using Cd(II) as a template ion, acrylonitrile and maleic acid as functional monomers, divinylbenzene as a cross-linker, and potassium persulfate as an initiator. UV–vis, SEM and FTIR were used for characterization, and the adsorption conditions were observed and optimized. The adsorption capacity and selectivity of Cd-I-MA-co-AN for Cd(II) were analyzed by flame atomic absorption spectrometry (FAAS). The results documented that the optimal pH, flow rate and eluent were 6, 2 mL min−1 and 1 mol L−1 nitric acid, respectively. Compared with the non-ion imprinted maleic acid-co-acrylonitrile polymeric microsphere (NI-MA-co-AN), Cd-I-MA-co-AN had a higher adsorption capacity. The saturated adsorption capacities of Cd-I-MA-co-AN and NI-MA-co-AN were 20.46 mg g−1 and 7.64 mg g−1, respectively. The adsorption behavior of Cd-I-MA-co-AN fitted with the Freundlich isotherm model. The relative selectivity coefficients of Cd-I-MA-co-AN for Cd(II) in the presence of Cu(II), Mn(II), Ni(II) and Pb(II) were 3.79, 3.39, 3.90 and 3.31, respectively. The Cd-I-MA-co-AN showed good selectivity for Cd(II). In addition, a reusability study showed that Cd-I-MA-co-AN can be recycled ten times and has high recovery in natural water samples.

Application of Molecularly Imprinted Polymers in the Analysis of Waters and Wastewaters

The increase of the global population and shortage of renewable water resources urges the development of possible remedies to improve the quality and reusability of waste and contaminated water supplies. Different water pollutants, such as heavy metals, dyes, pesticides, endocrine disrupting compounds (EDCs), and pharmaceuticals, are produced through continuous technical and industrial developments that are emerging with the increasing population. Molecularly imprinted polymers (MIPs) represent a class of synthetic receptors that can be produced from different types of polymerization reactions between a target template and functional monomer(s), having functional groups specifically interacting with the template; such interactions can be tailored according to the purpose of designing the polymer and based on the nature of the target compounds. The removal of the template using suitable knocking out agents renders a recognition cavity that can specifically rebind to the target template which is the main mechanism of the applicability of MIPs in electrochemical sensors and as solid phase extraction sorbents. MIPs have unique properties in terms of stability, selectivity, and resistance to acids and bases besides being of low cost and simple to prepare; thus, they are excellent materials to be used for water analysis. The current review represents the different applications of MIPs in the past five years for the detection of different classes of water and wastewater contaminants and possible approaches for future applications.