Read all posts from October 2014

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Thermo-responsive molecularly imprinted monolith in extraction

Molecularly imprinted polymers (MIPs) are widely employed sorbents due to their improved selectivity. They are synthesized in the presence of the analyte, which is called template, and therefore the polymeric network is constructed around the target leaving selective chemical cavities when it is washed away. After the bulk synthesis, the polymer is crashed and sieved to obtain a solid with a particle size as homogeneous as possible. In a recent article published in Analytical and Bioanalytical Chemistry, researchers from the Tianjin Medical University at China have proposed a smart MIP monolith for the extraction of ketoprofen from milk samples.Link to the post

Simultaneous electromembrane extraction of acidic and basic drugs

In most of the cases, microextraction techniques are applied to isolate and preconcentrate a target compound or a narrow group of them. The simultaneous extraction of a given sample into fractions of analytes with similar chemical characteristics is especially interesting in bioanalysis since biological samples contain plenty of compounds with biological effects that cover a wide range of polarities. Link to the post

Solid phase microextraction of volatile organic compounds from cigarette smoke

The determination of volatile compounds in gas samples is a challenging issue. Firstly, because it is difficult to collect large and representative samples and secondly due to the potential losses of the analyte by diffusion through the pores of the sample container. Moreover, the mandatory preconcentration step that must be implemented prior to the instrumental analysis must be carried out maintaining the sample homogeneity. Link to the post

Highlighted articles (October 16, 2014)

We recommend the following articles that deal with different aspects related with sample preparation. Link to the post

Octadecyl pipette tip coupled to electrospray ionization mass spectrometry

The availability of easy to handle interfaces for the direct analysis of samples by mass spectrometry is highly desirable as it clearly simplifies the analytical measurement process. Moreover, the reduction of errors in the final result given can be highlighted as a great advantage. These interfaces must reduce the amount of interferents that can eventually reach the detector while providing a reproducible and quantitative response. Link to the post

Highlighted articles (October 22, 2014)

We recommend the following articles that deal with different aspects related to sample preparation. Link to the post

Gas assisted micro liquid-liquid extraction: a simple and efficient technique for high throughput bioanalysis

The article that we highlight today describes a new, simple, efficient and automated extraction technique for high throughput bioanalysis. It has been published in Analytical Chemistry under the title "Gas Pressure Assisted Microliquid–Liquid Extraction Coupled Online to Direct Infusion Mass Spectrometry: A New Automated Screening Platform for Bioanalysis" (1). It is interesting to note that we have described another article from the same research group in a previous post. Link to the post

Highlighted articles (October 29, 2014)


We recommend the following articles that deal with different aspects related to sample preparation. Link to the post

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Gold coated magnetic beads for electrochemical detection

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

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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...
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Rotating Disk Sorptive Extraction

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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...
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