Applications of ultrasound-assisted emulsification

For the interest of analytical chemists, a large number of methods have been developed where ultrasonic emulsification is a key step in the determination of the target analytes. Most such methods are concerned with the determination of metallic elements in liquid 

Ultrasound Assistance to Heterogeneous Liquid-Liquid Systems 

Ultrasound-assisted emulsification in aqueous samples is the basis for the so-called liquid membrane process (LMP). This has been used mostly for the concentration and separation of metallic elements or other species such as weak acids and bases, hydrocarbons, gas mixtures and biologically important compounds such as amino acids [61-64]. LMP has aroused much interest as an alternative to conventional LLE. An LMP involves the previous preparation of the emulsion and its addition to the aqueous liquid sample. In this way, the continuous phase acts as a membrane between both the aqueous phases viz. those constituting the droplets and the sample). The separation principle is the diffusion of the target analytes from the sample to the droplets of the dispersed phase through the continuous phase. In comparison to conventional LLE, the emulsion-based method always affords easier, faster extraction and separation of the extract — which is sometimes mandatory in order to remove interferences from the organic solvents prior to detection. The formation and destruction of o/w or w/o emulsions by sonication have proved an effective method for extracting target species. 

One salient advantage of LMP is that it affords discrimination between different species of a given element by using emulsions containing a surfactant. This has been demonstrated 

Uitrasonic-assisted emuisification is commonpiace in the pharmaceuticai, cosmetic, food, chemicai and other industries. The target process is first studied at the iaboratory scaie in order to maximize emuisification efficiency at the iowest possibie cost. To this end, anaiyticai methods are frequentiy deveioped to examine the infiuence of variabies or new uitrasonic emuisifiers tested for this purpose. When favourabie resuits are obtained, the process is scaied-up to industriai ievei. 

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