PREPARATIVE ISOTACHOPHORETIC ANALYZER EQUIPPED WITH A DROPWISE FRACTIONATING DEVICE

A preparative isotachophoretic analyser with a series of four separation tubes of I.D. 0.5-5 mm was constructed and its fundamental efficiency was evaluated. The maximum injectable sample volume was 2.5 ml. The heat convection in the separation tube (I.D. = 5 mm) was suppressed by adding hydroxypropylcellulose to the leading electrolyte (1%) and sucrose to the terminating electrolyte (20%). The entire separated zones were fractionated dropwise (5.4 μl each) through a narrow-bore nozzle by a counter flow of the leading electrolyte. Variations in the course of dropping due to electrostatic forces were suppressed by a simple electrostatic device. The recoveries of several micrograms of separands were determined by photometric and PIXE analysis and were almost 100%. The separability and apparent sensitivity were very good; e.g., 150 ppb (109) Sm3+ (10-6 M, 2 ml) was separated from a mixture with Dy3+, Tm3+ and Lu3+. © 1990.