Microextraction Tech

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 ...

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...

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 with the intention of identifying potential drugs consumed by Mikhail Bulgakov to fight the nephrosis [1]. For this purpose, they have proposed a solid phase enrichment protocol using cation exchange (SCX) and hydrophobic (C8) beads of different particle sizes. In this proposal, wet beads are deposited on the manuscript surface and thanks to the different sizes (SCX have larger sizes than C8) a complete covering of the document with the particles is achieved. The targets are extracted by a mixed-mode mechanism and after the extraction, the final extracts are analyzed by GC/MS. Morphine T...

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 combination of physicochemical characteristics, than the individual solvents used in that mixture. In fact, our colleagues confirmed both aspects in a recent article published in Talanta [2]: According to the results, the enrichment factors obtained for the bubble in drop SDME (BID-SDME) are higher (ca. 1.5 times) than that obtained with the conventional SDME. The use of ...

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. In its conventional format, EME is developed in static mode. What would happen if the sample and even the acceptor phase are dynamically introduced in the extraction device? This question has been recently answered in an article published in Journal of Chromatography A [2]. Our colleagues have designed an extraction device where the sample and the acceptor phase can flow dynamically thanks to a peristaltic and a syringe pump, respectively. This configuration permits to process a larger sample volume (increasing the enrichment factor) without modifying the diffusion distance sample/acceptor phase. In fact, the flow of the sample...

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 (directly related to the extraction capacity) and they are usually related to the selectivity of the material through a shape/size restriction mechanism. This balance is not easy to achieve and some research groups are investigating in new synthesis procedures. Prof. Yu-Qi Feng and coworkers have recently proposed a new alternative in RSC Advances journal using a natural product, pomelo peel, as precursor [1]. The potential of the new material as well as the natural origin of one of the precursor (green chemistry) are highly remarkable...