Bubble-in- drop single drop microextraction with mixed solvents

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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 mixed solvents provided better signals (in the range of 2-4 times) than the obtained for the pure solvents.

In addition, the authors have selected a challenging analytical problem to test both hypothesis. They have proposed an analytical method for the determination of growth hormones in bovine urine. Competitive results, compared with those methodologies found in the literature, are reported. The limits of detection, in the low ng/mL, are remarkable.

References
[1] Bubbles in Solvent Microextraction: The Influence of Intentionally Introduced Bubbles on Extraction Efficiency. Link to the article
[2] Picogram-level quantification of some growth hormones in bovine urine using mixed-solvent bubble-in-drop single drop micro-extraction.Link to the article

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