The application of molecular imprinting technology to solid phase extraction

Abstract

SummaryIn parallel to a long lasting search for universal multi-purpose sorbents, the area ofsohd phase extraction (SPE) is recently experiencing a rapid development of new lypes of tailor-made class specific or compound-specific sorbents which are designed to respond to the increasing demand for selectivily and efficiency in sample clean-up prior to quantification. An important issue here is the enrichment and clean-up of complex samples, such as environmental waters, sediments, biofluids and foodstuffs prior to detection .This because the analyte is often present in low concentration in a complex mixture of similarcompounds and therefore needs to be isolated and enriched in order to be detected by standard analytical techniques.The fact that molecularly imprinted polymers (MIPs) can in principle be prepared against any low molecular weight target molecule, can endure harsh working conditions and work in organic solvents makes them extremely attractive as class or compou nd-specific sorbents.This review critically discusses the application of the technology of molecular imprinting to solid phase extraction with examples of the different approaches (off-hne, on-line, coupled column), the different sorbent formats (cartridge, membrane, solid phase microextraction (SPME)) and the different protocols (selective adsorption, selective desorption)taken from the literature.The issues involved in the development of a new MISPE protocol (choice of template, functional monomer, crosshnker, evaluation of the phase and validation of the extraction protocol) and the problems associated with the bleeding of non-extracted template are also discussed.

A Stoichiometric Molecularly Imprinted Polymer for the Class‐Selective Recognition of Antibiotics in Aqueous Media

“…[8] A few reports on the imprinting of antibiotics have appeared, [9][10][11][12][13][14][15] with one notable exception: [9] MIPs capable of selectively extracting penicillins from aqueous media have not been reported. This omission is because of the common reliance on the conventional noncovalent imprinting method in which the binding sites are templated through weak-to-medium strength interactions.…”

New Biosorbent Materials: Selectivity and Bioengineering Insights

“…Another possible scenario is that in many cases, the template molecule does not present enough solubility in the porogen and therefore, cannot participate in interactions with the cavity of MIP [46,47]. The results from the above are not simple: (i) the most possible is a reduction of the total number of cavities suitable for rebinding ( Figure 3); (ii) the template can be "escaped" during the last step of elution mainly in MIPs used in columns for solid phase extraction [48] or during analysis [49]. Even in the case of MIPs prepared with non-covalent or self-assembly technique, the binding of the template to the components of the imprinted cavity can be so strong that extraction under drastic conditions is required [51].…”

Application of dummy molecularly imprinted solid‐phase extraction in the analysis of cyproheptadine in bovine urine

“…As a rule, more than 1% of the template used in the prepolymer mixture remains bound in the polymer network, even after thorough washing of the MIP [30]. To optimize the template and dummy template, both target molecules were minimized with Gaussian 03 software [31] using density functional theory methods with the Becke three parameter hybrid Lee -Yang -Parr functional and the 3 -21 g basis set.…”