Molecularly imprinted polymer for the extraction and detection of insulin

By -
Since the development of solid phase microextraction (SPME), several alternatives for the fiber coating have been proposed to open the applicability of this microextraction technique to as much families of compounds as possible. Moreover, looking for higher selectivity is also a transversal research line in this methodology. Molecularly imprinted polymers (MIPs) can be used for this purpose although they are still scarcely used as coatings in SPME. MIP micro-solid phase extraction (MIMSPE) is a renovated version of MIP-SPME. The main difference between both techniques is the extent to which the analyte is extracted, being exhaustive for the formed which can be considered as a total recovery extraction method.

One of the latest articles published in Journal of Chromatography A combines MIMSPE with a multiwalled carbon nanotubes-MIP composite sensor. The main goal of this proposal is to achieve a high sensitivity thanks to the double preconcentration carried out in the extraction and detection steps which allows the determination of insulin at the ultra-trace levels. The selectivity is assured owing to the molecular recognition performed by the MIP.
Figure. Use of MIPs as extracting material and as a part of the sensing element in insulin determination
The selective SPME coating was immobilized in the silica fiber following two different procedures (viz, surface-attached and sol-gel) which are deeply described in the article. The performance og both coatings is exhaustively described in the manuscript through excellent figures, tables and micrographs. As a results, the authors concluded that the surface-attached mode was superior in terms of sensitivity, precision and stability. As far as cross-reactivity is concerned, non-specific adsorption of analytes and interferents were eliminated by subjecting the fibres to a 4-5 waters-washing cycles.

A final application of the method to human serum samples is described in the article with an interesting discussion of the influence of the sample dilution on the sensor response.. No doubt the proposal is of the highest relevance for the rapid and reliable diagnosis of insulin resistance disease.

Reference
(1) An insulin monitoring device based on hyphenation between molecularly imprinted micro-solid phase extraction and complementary molecularly imprinted polymer-sensor.Link to the article

Comments

Post a Comment

Popular posts from this blog

Gold coated magnetic beads for electrochemical detection

By -
Image
This post summarizes an interesting article, recently accepted for publication in Analytical Chemistry, which presents an innovative use of magnetic beads. Researchers from the Osaka Prefecture University at Japan have proposed the synthesis of magnetic microbeads covered with a smooth gold layer that are used for the electrochemical detection of streptavidin (1). The synthesis, which is deeply described in the manuscript, consists of three well defined steps. First of all, the magnetic beads are introduced in a colloidal gold dispersion containing Au-nanoparticles (Au-NPs). Thanks to the opposite zeta potential of both materials (microbeads are negatively charged while Au-NPs present a positive charge), their assembly takes place by electrostatic interactions. However, the Au-NPs are not connected to each other and therefore the electrical resistance of the microbeads is too high. In a second step, the modified microbeads are dispersed in an aqueous medium containing HAuCl 4 as ...
Read more

Fabric phase sorptive extraction: a new generation green sample preparation strategy

By -
Image
by Dr. Abuzar Kabir, International Forensic Research Institute, Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA Fabric phase sorptive extraction (FPSE), the most recent member of the sorptive microextraction family, has innovatively incorporated both solid phase microextraction (SPME) and solid phase extraction (SPE) techniques into a single technology platform. FPSE utilizes permeable natural/synthetic fabrics e.g., cotton, polyester, fiber glass supports to chemically bind sol-gel hybrid inorganic-inorganic sorbents. A 5 cm2unit of coated fabric (2.5 cm x 2.0 cm) is typically used as the extraction media which can be inserted directly into the sample container. Extraction of the analytes is generally expedited by using a magnetic stir bar to diffuse the analyts into the sample matrix so that rapid mass transfer from the sample matrix to the extraction medium takes place.Once the mass transfer equilibrium between the FPSE media and...
Read more

Rotating Disk Sorptive Extraction

By -
Image
by Prof. Dr. Pablo Richter, Department of Inorganic and Analytical Chemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile. The modern trends in analytical chemistry promote efficiency and green technology in sample preparation. In this context, our research team developed a new technique in 2009 that is capable of extracting pollutants from liquid samples on a rotating PTFE disk with one surface coated with an extraction phase [1]. The disk has embedded a miniature magnetic rod, which allows rotation. We have termed this procedure rotating-disk sorptive extraction (RDSE). RDSE is currently available in two configurations. In the classic version (Figure 1), the extraction phase is a polymeric film adhered to one side of the PTFE disk (configuration 1). In this configuration, polydimethylsiloxane (PDMS), nylon and octadecyl (C18) have been used as the sorptive material for the extraction of low-polarity analytes (Log Kow between 3 and 7) [1-12]. However...
Read more