Centrifugal Partition Chromatography. IV. Preparative Sample Purification and Partition Coefficient Determination

Abstract

Centrifugal Partition Chromatography (CPC) uses a liquid as a stationary phase. This liquid is held in channels by a centrifugal field. The ability of CPC to purify a sample was tested using a mixture of 2,2 pchlorophenyl-1,1,1-trichlorethane (DDT) and the corresponding dichlorethane (DDD). It is shown that, in one run, up to 675 mg of DDT can be purified at 100%, with a recovery ratio of 100% (baseline restoration between peaks) using the liquid system methanol (mobile phase)-hexane (stationary phase). The factors limiting the mass load are (i) the selectivity or partition coefficient difference between the solutes, (ii) the efficiency and (iii) the solute solubility in either of the phases. The mass load must be measured first by increasing the sample concentration of the injected solution, then by increasing the injection volume up to the point where peak overlap occurs. It is theoretically demonstrated that CPC can be used to determine partition coefficients over a five order of magnitude range, from 0.003 to 340, by adjusting the stationary phase volume.