Molecularly imprinted polymers in online extraction liquid chromatography methods: Current advances and recent applications

BACKGROUND

One of the primary objectives in green analytical practices is the seamless integration of extraction and separation steps, resulting in the augmentation of both analytical throughput and method performance. Consequently, the exploration of prospective sorbent materials has drawn significant attention in the scientific community, particularly concerning the potential for online procedures. Employing the optimal sorbent material within an automated analytical approach holds the promise of elevating the precision of the analytical evaluation. Molecularly imprinted polymers (MIPs) excel in specific analyte interaction within complex matrices. However, MIPs' full potential was not widely exploring especially for online analytical methodologies.

RESULTS

Here is presented a comprehensive overview of the current applications of MIPs as sorbent materials within integrated and automated separation methodologies applied to diverse matrices including biological, food, and environmental samples. Notably, their primary advantage, as evidenced in the literature, lies in their exceptional selectivity for the target analyte discussed according to the adopted synthesis protocol. Furthermore, the literature discussed here illustrates the versatility of MIPs in terms of modification with one or more phases which are so-called hybrid materials, such as molecularly imprinted monoliths (MIM), the molecularly imprinted ionic liquid polymer (IL-MIP), and restricted access to molecularly imprinted polymer (RAMIP). The reported advantages enhance their applicability in integrated and automated separation procedures, especially to the column switching methods, across a broader spectrum of applications.

SIGNIFICANCE

This revision aims to demonstrate the MIP's potential as a sorbent phase in integrated and automated methods, this comprehensive overview of MIP polymers in integrated and automated separation methodologies can be used as a valuable guide, inspiring new research on developing novel horizons for MIP applications to have their potential emphasized in analytical science and enhanced to the great analytical methods achievement.

Recent Advances in the Recognition Elements of Sensors to Detect Pyrethroids in Food: A Review

The presence of pyrethroids in food and the environment due to their excessive use and extensive application in the agriculture industry represents a significant threat to public health. Therefore, the determination of the presence of pyrethroids in foods by simple, rapid, and sensitive methods is warranted. Herein, recognition methods for pyrethroids based on electrochemical and optical biosensors from the last five years are reviewed, including surface-enhanced Raman scattering (SERS), surface plasmon resonance (SPR), chemiluminescence, biochemical, fluorescence, and colorimetric methods. In addition, recognition elements used for pyrethroid detection, including enzymes, antigens/antibodies, aptamers, and molecular-imprinted polymers, are classified and discussed based on the bioreceptor types. The current research status, the advantages and disadvantages of existing methods, and future development trends are discussed. The research progress of rapid pyrethroid detection in our laboratory is also presented.

The Use of Aptamers and Molecularly Imprinted Polymers in Biosensors for Environmental Monitoring: A Tale of Two Receptors

Effective molecular recognition remains a major challenge in the development of robust receptors for biosensing applications. Over the last three decades, aptamers and molecularly imprinted polymers (MIPs) have emerged as the receptors of choice for use in biosensors as viable alternatives to natural antibodies, due to their superior stability, comparable binding performance, and lower costs. Although both of these technologies have been developed in parallel, they both suffer from their own unique problems. In this review, we will compare and contrast both types of receptor, with a focus on the area of environmental monitoring. Firstly, we will discuss the strategies and challenges involved in their development. We will also discuss the challenges that are involved in interfacing them with the biosensors. We will then compare and contrast their performance with a focus on their use in the detection of environmental contaminants, namely, antibiotics, pesticides, heavy metals, and pathogens detection. Finally, we will discuss the future direction of these two technologies.

Retention and molecular-recognition mechanisms of molecularly imprinted polymers for promazine derivatives

Monodisperse molecularly imprinted polymers (MIPs) for promazine derivatives [promazine (PZ), methylpromazine (MPZ), chlorpromazine (CPZ) and bromopromazine (BPZ)], MIP_PZ, MIP_MPZ, MIP_CPZ and MIP_BPZ, were prepared using methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate as a crosslinker by multi-step swelling and polymerization. The retention and molecular-recognition properties of the obtained MIPs were evaluated using LC in hydrophilic interaction chromatography (HILIC) and reversed-phase modes. In computational approaches, intermolecular interaction modes and energies between PZ derivatives and MAAs were evaluated at the HF/6-311G(d,p) level. The interaction energies of PZ, MPZ, CPZ and BPZ with 4 equivalents of MAAs were calculated. The results indicated that the interaction of the aliphatic amine moiety of a PZ derivative with MAA gave almost similar interaction energies at the HF/6-311G(d,p) level, and that the interaction of the sulfur atom of a phenothiazine scaffold with MAA was also the case. The third interaction of the aromatic amine of a PZ derivative with MAA was in the order of MPZ > PZ > CPZ > BPZ presumably due to the change of basicity by the electron-donating or electron-withdrawing effect of a subsituent. Furthermore, the fourth attractive modes of CPZ and BPZ were suggested to be the interaction of their halogen atoms with MAA through both halogen bonding and hydrogen bonding, while PZ and MPZ were suggested to have the weak C-H ⋅⋅⋅ π interaction with MAA. In HILIC mode, the interaction energies at the HF method had good correlation with the retention factor of a PZ derivative on each MIP, indicating that in addition to the shape recognition, the attractive electrostatic interactions would be more responsible for its retention rather than the dispersion energies. Furthermore, in addition to the shape recognition, ionic and hydrophobic interactions, and halogen bonding and hydrogen bonding (the last interaction seems to be weak) seem to work for the retention and molecular-recognition of PZ derivatives on the MIPs in reversed-phase mode.