A SPE Method with Two MIPs in Two Steps for Improving the Selectivity of MIPs

Abstract

Molecular imprinted polymers (MIPs) have been widely applied in the separation of compounds in complex matrixes due to the high selectivity for molecular recognition. However, MIPs not only adsorb the targeted molecule but also adsorb structurally similar analogues, which leads to some loss of selectivity. In this work, for improvement of selectivity of MIPs, a novel solid-phase extraction method with two MIPs in two steps (TMIPs-TSPE) was established. As a demonstration, two MIPs were prepared by using quercetin as the template and 4-vinylypyridine (4VP) and acrylamide (AM) as representative functional monomers, respectively. The adsorption properties and kinetic characteristics of the two MIPs showed that they had a distinct adsorption capacity and adsorption mechanism, which is the basis for establishment of TMIPs-TSPE. The TMIPs-TSPE method first used one of the two MIPs as adsorbent to extract molecules from a solution mixture containing quercetin and three analogues. Then the other MIP was used to achieve a second extraction of the extracted molecules from the first step. The results showed that the unique targeted molecule quercetin was extracted, which illustrates that TMIPs-TSPE improved the specificity of the MIPs. The process of molecular recognition can be influenced by the intensity of binding sites between MIPs and molecules. Moreover, it may also depend on the spatial orientation of molecules entering the cavities of MIPs, which deserves more attention as one important property for the development of molecular imprinting. These results demonstrated that the novel TMIPs-TSPE method contributes to the improved selectivity of MIPs.

Hydrophilic molecularly imprinted nanospheres for the extraction of rhodamine B followed by HPLC analysis: A green approach and hazardous waste elimination

“…As presented in Fig. S1c, MINs had two different lines while NINs had one line, which revealed the presence of two different kinds of adsorption sites in MINs while only one kind of adsorption site in NINs network, respectively [29]. The Scatchard parameters of MINs including K a , K d , and Q m were obtained to be 3.0712 mg L −1 , 0.325 mg L −1 and 24.97 mg g −1 for the specific (high-affinity) binding sites, respectively, and 0.3684 mg L −1 , 2.71 mg L −1 and 42.49 mg g −1 for the non-specific (low-affinity) binding sites, respectively, while K a , K d , and Q m of NINs were achieved to be 0.0246 mg L −1 , 40.65 mg L −1 and 19.58 mg g −1 according to the slopes and intercepts of the obtained plots, as listed in Table S2.…”

Selective removal of contaminants of emerging concern (CECs) from urban water cycle via Molecularly Imprinted Polymers (MIPs): Potential of upscaling and enabling reclaimed water reuse

“…For example, methacrylic acid [95] and 2-vinyl pyridine [65] were used in similar synthesis, through precipitation polymerization, for the selective removal of diclofenac but, due to the different chemical interactions between the monomers and the diclofenac, the two obtained polymers exhibited different adsorption efficiencies, around 65 mg/g and 350 mg/g, respectively. Another example is given by Huang et al [108], who described the synthesis of two different MIPs for the selective extraction of quercetin, through bulk polymerization using two monomers, 4-vinylpirydine (MIP-4VP) and acrylamide (MIP-AM). In this study, two SPE cartridges were filled with the two polymers and sequentially used to increase the selective removal of quercetin from a mixture with other analogue compounds.…”

Dummy Molecularly Imprinted Polymers Using DNP as a Template Molecule for Explosive Sensing and Nitroaromatic Compound Discrimination

“…MIPs acting as artificial receptors have demonstrated their applicability in several fields; among these, we can note the food industry [1,2], environmental monitoring [3,4], clinical diagnosis [5,6] and forensic field [7]. MIPs are perfect candidates to improve the performance of current analytical methods due to their versatility, functionality, and ability to sample pre-concentration [8], separation [9] and/or purification [10]; alternatively, they may be used as a recognition element for the development of different biosensing strategies [11,12] and also in drug delivery [13].…”