Microextraction Tech

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...

We recommend the following articles that deal with different aspects related to sample preparation. 1. Development of combined salt- and air-assisted liquid–liquid microextraction as a novel sample preparation technique. Air assisted liquid-liquid microextraction is an interesting technique that uses air to assist the dispersion of the extractant solvent into the sample. It is usually performed by adding a small volume of extractant to the sample, the resulting mixture being sucked several times by a glass syringe. The process generates an efficient dispersion of the solvent and a final centrifugation is required to recover the acceptor phase for its final analysis. In this article, the authors face up the phases separation using a gas stream to break the emulsion and to recover a low volume of organic solvent (typically 10 µL). This proposal has been evaluated for the determination of β-naphtol, naphthalene and anthracene in water and wastewater. This article merits attention a...

We recommend the following articles that deal with different aspects related to sample preparation. 1. Coumarins as turn on/off fluorescent probes for detection of residual acetone in cosmetics following headspace single-drop microextraction. This article presents an interesting application of HS-SDME for the indirect determination of acetone residues in cosmetics. The method takes advantage of the special characteristics of the native fluorescence of coumarins whose intensity depends, among other factors, on the chemical composition of the medium where they are dissolved. In fact, the fluorescence intensity of an ethanol/water solution of 7-diethylamino-4- methylcoumarin (MDAC) increases in the presence of acetone while the intensity of an ethanol/water solution of 7-hydroxy-4-methylcoumarin (4-MU) decreases when acetone is dissolved in that medium. These are the so-called turn-on and turn-off fluorescent effects. In short, the method comprises different steps. First of all, a de...

We recommend the following articles that deal with different aspects related to sample preparation. 1. Energy-dispersive X-ray spectrometry combined with directly suspended droplet microextraction for determination of dissolved silicate in surface water via silico molybdenum blue complex. Dr. Pytlakowska from the University of Silesia (Poland) faces up the determination of silicate in samples by energy-dispersive X-ray spectrometry, which is not especially sensitive for this determination due to the low energy of the Kα line of silicon. In order to overcome this limitation, a indirect method based on the use of molybdenum (a more intense emitter) as marker is proposed. For this purpose, silicate is transformed into silicomolybdenum blue which is finally isolated and preconcentrated by means of suspended droplet microextraction. After the extraction, the organic solvent is deposited over a polymeric membrane where molybdenum (whose concentration is related to the original silicate ...

We recommend the following articles that deal with different aspects related with sample preparation. 1. Molecularly imprinted polymer dedicated to the extraction of glyphosate in natural waters . Glyphosate is a widely employed pesticide. Glyphosate determination is challenging due to its small size and high polarity. In this article, researchers from the University of Orleans at France have proposed a new molecularly imprinted polymer (MIP) that allows, thanks to electrostatic and polar interactions, the isolation of this analyte from natural waters. The MIP showed higher selective recognition toward the target analyte than the obtained with the non-imprinted polymer (NIP). Although the pH and ionic strength are critical variables on the analyte extraction, this method is a promising tool for the resolution of this complex analytical problem.  Link to the article 2. Water-contained surfactant-based vortex-assisted microextraction method combined with liquid chromatograph...