Motorized syringe methods

The following contribution compU recently published cyclizations. Most of these examples have not been included in our former survey on the dilution principle [3 a] and are thought as a continuation and update of that former survey up to 1990. As shown there, some characteristic experimental standard methods are specified here as well. (For a standard apparatus and a modified motor-driven syringe-type version see [3d, e].)... 

If the system contains three constituents with different mobilities, three boundaries will form a rate of movement equal in magnitude, but opposite in direction, to that of the middle boundary is now imparted to the whole liquid. The fastest moving constituent moves ahead, whereas the slowest constituent is given an apparent negative velocity after electrophoresis has proceeded for some time, one limb of the section C contains the former constituent and the other contains the latter in a pure form. Several devices have been employed to impart a movement to the liquid one method is to withdraw gradually, by means of clockwork, a plunger which fits loosely into one of ihe electrode vessels, while another is to keep one electrode vessel closed, e.g., the left-hand one in Fig. 131, and to force buffer solution into it at the desired rate by means of a syringe operated by a constant speed motor. 

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