A Study of the Various Factors That Affect the Properties of Molecularly Imprinted Polymers

Abstract

We evaluated the adsorbability and selectivity of (S)-valine anilide imprinted molecularly imprinted polymer (MIP) using a batch procedure that is both independent and precise. This study revealed important information about the relationship between the performance of MIPs and experimental factors such as the components of MIP synthesis and a reaction solvent. Herein, we also describe the problems associated with the preparation of a "non-imprinted polymer," which is often used to evaluate the effect of a template molecule, and we propose a new type of reference polymer, "blank polymer." Key words (S)-valine anilide; molecular imprinting; chiral recognition; non-imprinted polymer; blank polymer Molecularly imprinted polymers (MIPs) [1][2][3][4] are widely used as a powerful tool for molecular recognition, due to their high adsorbability and selectivity. Although several methods are available to evaluate the performance of MIPs, the measurement of the separating factor (α-value) using an HPLC column filled with a MIP as a stationary phase 5,6) is the most commonly adopted method owing to its simplicity and practical utility.The α-value, however, is affected by many chromatographically experimental factors such as the type of eluent (mobile phase), 7) the substrate, 8) and the theoretical plate number of the column, and it depends on a large number of recycling adsorption-desorption processes in the stationary phase.The batch procedure, 9) on the other hand, directly measures the concentration of the substrate in a reaction mixture, which allows the precise and independent observation of adsorbability and selectivity. Hence, the batch procedure would be amenable in a study of the relationship between the synthesis conditions of a MIP and its ability.During the course of our trial to evaluate the performance of MIPs using the batch procedure, we gained important information about the relationship between the performance of MIPs and the many factors involved in the processes of synthesis and measurement.In this paper, we report the factors that directly affected the properties of the MIPs. We also describe the problems associated with the preparation of a "blank polymer," which is often used as a reference polymer for the sake of comparison.

A Study of the Strength of a Template Molecule—A Functional Monomer Interaction That Affects the Performance of Molecularly Imprinted Polymers and Its Application to Chiral Amplification

“…As described above, IP-2 was prepared using hydrogen-bonding interactions as a main force in the prepolymerization step and IP-1 was similarly prepared using an acid-base interaction. 13) Despite the lack of a stronger acidbase interaction that was advantageous for molding the recognition sites, surprisingly, IP-2 showed a higher stereoselectivity than expected (entry 1). In CH 2 Cl 2 , N-benzoylvaline anilide exhibited lower adsorbability onto IP-2 than that of a valine anilide onto IP-1 (see Table 3, entry 2).…”

“…Comparison of Substrates In our previous report, we found that IP-1 synthesized using (S)-valine anilide as a template molecule, with the aid of a stronger acid-base interaction than hydrogen bonding, could recognize not only the enantiomers of a template molecule but also those of similar amino acid derivatives (Ala, Phe and t-Leu anilides), which showed similar enantioselectivities for all substrates, but also variations in the amount of adsorbed substrates 13) (Table 3). Based on such curious results, we next evaluated the adsorbabilities and enantioselectivities of IP-2 toward various types of N-benzoyl amino acid anilides (Table 4).…”

“…We previously reported 13) the evaluation of basic (S)-amino acid anilide (such as (S)-1)-imprinted MIPs that were prepared using an acid-base interaction by batch procedure that allowed independent observation of adsorbability and selectivity, which were not precisely measured by a HPLC column system.…”

Synthesis and Characterization of Fomesafen Imprinted Polymers

“…When the concentration of fomesafen was over 160 mg¢L ¡1 , all adsorption curve became relatively flat. In the non-imprinting process, functional monomer were distributed randomly and most of the MAA would form a dimmer, the multipoint interactions were much weaker and there was a limited amount of free carboxylic acid to interact with the carbonyl, leading to low adsorbability (16)(17). Compared with adsorption of MIP2 and NIP2 at low concentration ranging from 20 to 80 mg¢L ¡1 , the gap between MIP2 and NIP2 were not particularly large.…”

Computational Investigation of the Monomer Ratio and Solvent Environment for the Complex Formed between Sulfamethoxazole and Functional Monomer Methacrylic Acid

“…Due to their stability in extreme conditions, MIPs have been drawing the attention of many industries, like pharmaceuticals. − Because of the properties of MIPs, their use in antibiotic detection in food and environmental samples, which have gained importance from the study areas of biochemical molecules, is also essential. However, their properties are directly affected by important parameters , such as monomer–template type, interaction strength between them, and solvent type, which requires serious planning before synthesizing MIPs. Investigating these parameters involves many laborious tests , and experiments.…”