Microextraction Tech

In most of the applications, microextraction techniques are employed to isolate and/or enrich target analytes from a given sample in order to make easier (more selective and sensitive) their final determination by an appropriate instrumental technique. However, the versatility of these techniques allows their use in the determination of chemical constants. Researchers from the University of Alicante at Spain have developed a vortex assisted liquid-liquid microextraction (VALLME) procedure to determine the octanol-water partition coefficient (K ow ) in a simple way. K ow is an important parameter that can be used for different purposes like the studies of the bioaccumulation rates of toxicants since K ow is similar to the lipid-water partition coefficient or the proper selection of an extractant in a extraction technique since K ow provides information about the polarity of a compound. In brief, the proposed VALLME procedure consist on the addition of 50 µL of 1-octanol to 10 mL...

We list here some recent articles dedicated to sample preparation (or interesting aspects related to it) which are freely available on internet: 1. An update for human blood plasma pretreatment for optimized recovery of low-molecular-mass peptides prior to CE–MS and SPE–CE–MS http://bit.ly/1b8dfl9 2. Challenges and new directions in analytical sample preparation http://bit.ly/Lqq18Y 3. Pressurised hot water extraction in continuous flow mode for thermolabile compounds: extraction of polyphenols in red onions http://bit.ly/1kGVxPA 4. ICP-MS-based characterization of inorganic nanoparticles—sample preparation and off-line fractionation strategies http://bit.ly/1j9ciPi 5. Single-drop microextraction for bioanalysis: present and future http://bit.ly/1aHLVdP 6. Nanomaterials in Analytical Chemistry http://bit.ly/19KPkx7 7. Organic Solvent-Free Cloud Point Extraction-like Methodology Using Aggregation of Graphene Oxide http://bit.ly/19KQ5q4 8. Influence of P...

We list here some recent articles dedicated to extraction techniques which are freely available on internet: 1. Dynamic solid phase microextraction analysis for airbornemethamphetamine: quantitation using isotopically substituted methamphetamine http://rsc.li/1klwykM 2. Novel Sorbents for Solid–Liquid Extraction http://bit.ly/1a8mZMf 3. Detection of methamphetamine in indoor air using dynamic solid phase microextraction: a supplementary method to surface wipe sampling http://rsc.li/1a8fNQj 4. Optimization of solid phase extraction chromatography for the separation of Np from U and Pu using experimental design tools in complex matrices http://rsc.li/1aHg6S7 5. Optimisation of the solvent extraction of bioactive compounds from Lophatherum gracile  Brongn. using response surface methodology and HPLC-PAD coupled with pre-column antioxidant assay http://rsc.li/1dfKNDM 6. Preconcentration and determination of bisphenol A, naphthol and dinitrophenol from envi...

We list here the most cited articles in microextraction techniques. In this case, the literature survey has been developed searching "microextraction" in article titles, abstracts and keywords. 1. Determination of organic compounds in water using dispersive liquid–liquid microextraction.  Link 2. Headspace solid-phase microextraction.  Link 3. Stir bar sorptive extraction (SBSE), a novel extraction technique for aqueous samples: Theory and principles .  Link 4. Solvent Microextraction into a Single Drop.  Link 5. Solid-Phase Microextraction. A Solvent-Free Alternative for Sample Preparation.  Link 6. Liquid−Liquid−Liquid Microextraction for Sample Preparation of Biological Fluids Prior to Capillary Electrophoresis.  Link 7. Applications of solid-phase microextraction in food analysis.  Link 8. Evolution of solid-phase microextraction technology.  Link 9. Dynamics of organic compound extraction from water using ...

We list here some Analytical Chemistry conferences that will take place throughout the year. Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. Pittcon 2014. Summary from the official webpage: Pittcon’s target audience is not just “analytical chemists”, but all laboratory scientists – anyone who identifies, quantifies, analyzes or tests the chemical or biological properties of compounds or molecules, or who manages these laboratory scientists. Having grown beyond its roots in analytical chemistry and spectroscopy, Pittcon has evolved into a conference & expo that now also serves a diverse constituency encompassing life sciences, pharmaceutical discovery and QA, food safety, environmental and bioterrorism markets. Dates: 2 March 2014 -- 7 March 2014. Location: Chicago, IL, United Sates http://pittcon.org/ ExTech2014. 16 th International Symposium on Advances in Extraction Technologies. Summary from the official webpage : The ExTech sy...

Cyclodextrins (CDs) are cyclic (R-1,4)-linked oligosacharides that consist of 6 (α- CD), 7 (β-CD) or 8 (γ-CD) glucopyranose subunits. They present a characteristic cage-like structure which allows to host molecules that present an appropriate dimension and polarity (Figure 1). In fact, the supramolecular structure posses an hydrophilic external surface and a hydrophophic cavity which make cyclodextrins useful to dissolve non-polar compounds in polar environments. The non-polar compounds form inclusion complexes with the cyclodextrin cavities involving non-covalent bonds which makes this interaction reversible.   Figure 1. Chemical and conformation structures of  γ-CD    The dimensions of cyclodextrins are defined in terms of outer diameter, cavity diameter, height of torus and cavity volume (Figure 2). These dimensions depend directly on the number of glucopyranose subunits and mark the type of analytes that are able to enter in the cavity to form an inclusi...

The use of nylon membranes modified with carbon nanotubes (CNTs) for the determination of caffeine in biological fluids has been proposed by researchers from San Luis University at Argentina (1). The proposed configuration is based on the retention of the analyte into the modified membrane and its in-surface determination by means of solid surface fluorescence (SSF). Although caffeine is not a fluorescent molecule, this methodology takes advantage of the interaction between caffeine and Rhodamine B which produces an enhancement of the native fluorescence of this dye.   (a) Rhodamine B   (b) Caffeine Modified membranes are easily fabricated by impregnation of the bare membranes with a solution that contains Rhodamine B, activated CNTs and hexadecyltrimethylammonium bromide (HTAB), the latter being a cationic surfactant employed for CNTs dispersion. After a drying step the membranes are ready to isolate caffeine from biological samples. The extraction procedure makes us...