Preparative Isotachophoresis

Isotachophoresis can also be employed for preparative purposes. However, the term ‘preparative ‘ needs to be clearly defined   The term preparative often suggests large sample sizes and, although this may often be the case in certain preparative systems, e.g. preparative chromatography, it is not the true meaning of the term when used in a general sense. Preparative is usually applied to the concept of sample collection, after separation i.e. the material that is separated is then collected for some other use such as spectroscopic examination organoleptic tests etc. In most cases sample sizes in preparative systems are indeed somewhat larger than analytical samples (which may be very small indeed) but the magnitude of the preparative sample will often be less than an order of magnitude greater than the analytical sample. Whereas in gas chromatography, for example, the preparative sample size may be three or four orders of magnitude greater than the analytical sample size.

In isothachophoresis the preparative sample sizes are not normally very large but the apparatus is designed so that the separated component of the sample can be easily collected without interfering with the separating process.

There are two common preparative isotachophoresis procedures, flat bead preparative isotachophoresis and column preparative isothachophoresis. Only the column procedure will be discussed here.