Microextraction Tech

In 2014 a new method for the synthesis of magnetic nanoparticles (MNPs)-nylon 6 composite was proposed. This method is simple and quick since only one step is needed. It is based on a solvent changeover, taking advantage of the different solubility of nylon 6 in formic acid and water. In Figure 1, it can be observed how this synthesis is carried out. The solution of MNPs and nylon-6 in formic acid is added to a beaker with water using a plastic syringe, inducing the precipitation of the polymer around the MNPs. To collect the composite after the synthesis, a magnet is used. Figure 1. Scheme of the synthesis When MNPs are combined with a polymer, the resulting composite has the properties of both materials, combining the high extraction capabilities of the polymer and the magnetic behaviour due to the nanoparticles. Moreover, another advantage of using polymers is their wide versatility since they can be tailored-synthesized and different functional groups can be added, to reac...

Freeze concentration (FC) is a separation technique scarcely exploited for sample treatment in Analytical Chemistry although it has been successfully applied in the industrial field. For example, FC is used in the food industry to extract water avoiding losses of (semi)volatile and thermolabile compounds producing extracts enriched in the solutes of interest. FC is based on the fact that solutions (water plus solutes) have lower freezing points than pure water. Therefore, when a solution is cooled down at an appropriate temperature, ice crystals start to be formed excluding solutes which are concentrated in the remaining liquid phase. Prof. Logues´s research group at South Dakota State University (USA) have applied this principle in an innovative way to improve the extraction yield of stir bar sorptive extraction (SBSE). The overall extraction procedure is quite simple as it only requires cooling the vial that contains the sample while SBSE is performed. The cooling of the sample...

Optical monitoring of single drop microextraction Single drop microextraction, the first liquid phase microextraction technique, is a simple approach consisting of the extraction of the target analytes from the sample into a small drop of extractant. The characteristics of the drop, specially its chemical nature and mechanical stability, are key to guarantee the success of the extraction. The chemical composition defines the affinity towards the target analytes which are, in fact, extracted depending on their solubility. The mechanical stability of the drop during the extraction is critical since the drop detachment would ruin the extraction. (Read the post) Moving miniaturization a step forward Microextraction techniques have evolved from classical extraction procedures following three main trends, namely: miniaturization, simplification and automation, which have not received a similar attention in the last decades. In fact, simplification and miniaturization (in different d...