Portable stir bar stirrer for on-site extractions

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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 faced up by researchers form the Wuhan University at China. In a recent article, accepted for publication in the Journal of Chromatography A, these authors have proposed a portable stir bar stirrer for on-site extractions. The proposal is based on a miniature electric stirrer equipped with a magnetic stir rod where a polydimethylsiloxane (PDMS) stir bar, prepared in the lab by a sol-gel method, is attached by magnetic forces. (figure 1)

Figure 1. Adapated figure presenting the proposal. For details, read the referenced article
The new prototype was evaluated for the extraction of some polycyclic aromatic hydrocarbons (PAHs) form water samples under three different extraction modes: direct immersion, headspace extraction and dynamic extraction. All these extraction modes were optimized considering the main experimental variables as well as analytically characterized. Compared with other conventional approaches, the proposal provides a better sensitivity.

Readers are referred to the original article where they will find the description of the preparation of the PDMS stir bar and the explanation of the extraction device. Moreover it is highly recommendable the study performed about the stability of the PAHs under different storage conditions and also the optimization and characterization of the extraction modes.

References:
(1) Stir bar sorptive extraction approaches with a home-made portable electric stirrer for the analysis of polycyclic aromatic hydrocarbon compounds in environmental water. Link to the article

Comments

  1. UnknownJanuary 7, 2016 at 4:13 AM

    We are the Manufacturer of magnetic stirring rod is helps to pop in & confiscate the bars from solution. Plastic Magnetic Stirrer Retrievers / Rescures at wholesale competitive prices from India. For more details check out our website.

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