Ultrasound-assisted extraction and in situ derivatization

•The favorable effect of ultrasound (US) on mass transfer between two phases is emphasized.•The synergistic effect of US on mass-transfer and in situ chemical reaction is shown.•Both steps can be developed at the microscale size and assisted by an US microprobe.

Ultrasound (US) is a type of energy of growing interest for analytical chemists. The favorable effect of US on mass transfer between two phases in the same or different state has been widely demonstrated as did the number of chemical reactions accelerated/improved under ultrasonic influence. The action of US on both mass transfer and chemical reaction developed in a simultaneous manner results in a synergistic effect as a consequence of the “removal” of the target extracted species by conversion into a product. Both US-assisted solid–liquid extraction and liquid–liquid extraction have been developed with in situ derivatization at the meso- and microscale and the advantages involved in their implementation are discussed in this article.