Scope of ultrasound-assisted soft digestion

Dissolution is usually performed by suspending the solid sample in a vessel containing a solvent and agitating the mixture by manual or mechanical stirring or shaking to ensure complete transfer of the solid into the liquid phase. This operation is normally carried out 

Dissoiution as a sampie preparation step is preferred to ieaching and the physioai removai of anaiytes when the sampie oan be easiiy soiubiiized without the need for exhaustive or drastic treatment. There are obvious advantages in the simpiicity of the dissoiution operation e.g. the need for no operator training and the abiiity to perform the dissoiution in an automated way by, for exampie, using a robotio approach). 

Although clean-up and preconcentration help to improve the selectivity of dissolution and offset the dilution effeot, they lengthen the analytical process. This drawback should always be borne in mind in view of the growing tendency to shorten the analytical process so as to analyse as many samples as possible in the shortest time. It is always preferable to use selective steps such as leaching, pervaporation or headspace to remove the analytes from a solid sample. However, very frequently, they fail to provide quantitative results owing to inadequate efficienoy and (or) preoision. In this situation, USASD is an effective alternative to ensure complete transfer of analytes to a liquid phase and hence the quality in the results. 

As previously stated, both ultrasonio baths and probes can be used for USASD, both in discrete and continuous approaohes. Thus, the choice of an ultrasonio bath or a probe will depend on the particular treatment to be applied. If a bath provides enough energy 

Probes supply more powerful energy also. In the absence of highly reactive chemicals, the tip can be directly Inserted Into the digestion medium. 

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