Microextraction Tech

Zinc oxide has been used as coating in solid phase microextraction (SPME) due to its good properties including thermal stability and affinity towards different analytes. In this sense, ZnO presents a high interaction with sulfur-containing molecules due to the strong coordination between Zn and S. However, this interaction is not completely exploited in SPME since pure ZnO coatings, prepared by sol-gel procedures, have a low surface area due to the enwrapping of ZnO nanoparticles (NPs) in the sol-gel network. In a recent article accepted for publication in Journal of Chromatography A, researchers from the Sun Ya-sen University at China have proposed a new approach to avoid this shortcoming. The proposal consists of the use of graphene as ZnO NPs support. The ZnO NPs are grown in the graphene (G) surface producing a composite which is final attached to a silica fiber by a sol-gel reaction in order to prepare the SPME coating. The whole synthetic procedure is described in detai...

On-site solid phase extraction is specially indicated for those analytes which present a limited stability in the sample matrix. The procedure consists of the extraction of the sample immediately after its sampling and the final storage of the sorbent , containing the target analytes , until the final analysis which is usually performed in a conventional lab. Moreover, on-site extraction presents additional advantages in environmental analysis such as the simplification of the sample storage and transportation processes as only the sorbent with the extracted analytes has to be stocked up. The potential of stir bar sorptive extraction (SBSE) for the extraction of organic pollutants, especially for the most hydrophobic ones, from water samples is clearly demonstrated in the scientific literature. However, the applicability of the SBSE in on-site extraction is limited as it usually requires a large size magnetic stirrer powered by alternating current. This limitation has been face...

The fabrication of liquid chromatographic columns with variable interaction chemistry (dual, sequential or gradient composition) is a challenge issue although it presents a high potential for separation and extraction purposes. The direct packing of the stationary phase in a column, the usual way for homogeneous phases, results unpractical when heterogeneous materials are used. Moreover, the final stationary phase´ characterization becomes difficult since it should be performed directly on the stationary phase holder. In this context, the easy in-situ synthesis of monolithic materials makes them a good alternative of choice compared to classic phases. The easy derivatization of the monoliths is also a crucial aspect. In a recent article, accepted for publication in Microchemical Journal, Currivan et al. have proposed an acrylate-based monolith with integrated gold nanoparticles for the successive extraction and separation of target proteins in the same column (1). The proposed ...