OPTIMIZATION OF EXPERIMENTAL CONDITIONS IN PREPARATIVE LIQUID-CHROMATOGRAPHY - TRADE-OFFS BETWEEN RECOVERY YIELD AND PRODUCTION-RATE

The optimization of the experimental conditions in preparative chromatography under constraints of recovery yield, product purity and maximum available pressure is discussed. It is shown that there are optimum values of the loading factor and the column limit efficiency which permit the achievement of the maximum production rate under specified constraints of recovery yield and product purity. The optimum loading factor is given by a simple equation. The optimum column efficiency is calculated from numerical solutions of the semi-ideal model. The optimum column length for a given packing material and particle size and the optimum mobile phase velocity are then derived. These optimum values depend on the maximum available pressure, and the production rate increases rapidly with increasing pressure. If a given column is available and it is shorter than the optimum length, it should be operated at the optimum loading factor and at the optimum column efficiency. The mobile phase velocity, and hence the production rate, are less than those for the column of optimum length. If the column is longer than the optimum and cannot be cut, it should be operated at the maximum available pressure, at a mobile phase velocity lower than the optimum and with a loading factor larger than the optimum.