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Using pomelo peel for the synthesis of monolithic ordered mesoporous silica

Monolithic ordered mesoporous silicas are highly attractive as sorbents in extraction techniques due to their physicochemical characteristics. To be really effective, there must be a balance between their macroporous and mesoporous structure. Macropores enhance the extraction kinetics allowing an easier diffusion of the target compounds from the bulk samples to the active surface of the material. Mesoporous defines the active surface of the material....Link to the post

Dynamic electromembrane extraction

The potential of electromembrane extraction (EME) is beyond any doubt [1]. As you well know, it is based on the electromigration of the target charged analyte from the donor phase (the sample) to the aqueous acceptor phase through a polymeric membrane that physically separates both phases. The extraction is rapid and it provides high enrichment factors......Link to the post

Bubble-in- drop single drop microextraction with mixed solvents

The intentional incorporation of air bubbles to solvent drops enhances the extraction efficiency in single drop microextraction (SDME). The reason behind this experimental fact is simple: the air bubble increases the surface to volume ratio of the drop. In other words, the same organic solvent volume presents a larger surface and therefore a better extraction kinetics. This idea, which was firstly proposed by Williams et al. in 2011, [1] has been recently revisited by the same research group proposing mixed solvents as extractant. Mixed solvents can present even better extraction properties, due to special....Link to the post



The study of historical documents: morphine in Bulgakov´s famous manuscript

Mikhail Bulgakov was a recognized writer born in Kiev in 1891. His famous novel, The master and Margarita, criticizes the soviet society and the literature establishment. He wrote the novel by the end of his life. In these days, Bulgakov was suffering nephrosis that caused his death in 1940. Researchers from Italy and Israel have chemically evaluated the original manuscript of the novel.....Link to the post



Highlighted articles (November 27th, 2015)


(1) Application of graphitic sorbent for on-line microextraction of drugs in human plasma samples. (2) In-line coupling of single drop microextraction with capillary electrophoresis-mass spectrometry. 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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Highlighted articles (November 27th, 2015)

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We recommend the following articles that deal with different aspects related with sample preparation. 1. Application of graphitic sorbent for on-line microextraction of drugs in human plasma samples . Graphitic carbon has a great potential as sorbent since it may develop different interaction chemistries with target compounds. Commercial graphitic carbons like graphitized carbon black or porous graphitic carbon presents some disadvantages including a lack of mechanical stability or a high retention (almost irreversible) of some analytes. These shortcomings are faced in this article where a new carbon material is presented. The new material is based on the deposition of a graphitic carbon layer over an inert substrate like alumina. This combination increases the mechanical strength which is key for chromatographic uses. The material has been packed in a lab made microextraction in packed sorbent (MEPS) device and it has been applied for the extraction of ropivacaine and lidocaine f
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