Analytical Systems

At the current state of development, high-resolu-tion liquid chromatographs for analyses of complex physiologic fluids require relatively long analysis times and consequently the rate at which analyses can be done is limited. This rate can be increased by decreasing the analysis time or by use of mul-tiple columnsto process several samples in unison. An automated multicolumn high.resolution chro-matogra ph for sepa rating ultraviolet-absorbing molecular constituents of body fluids is being de-veloped. The samplehandling capacity was in-creased several-fold with minimum added cost by using many of the components of the single-column analyzer. Results from routine use of a UV-Analyzer with two columns in parallel show that parallel operation is not only feasible but highly advantageous. The design of a high-pressure, mul-tiple-column, sample injection valve for simul-taneous injection of samples on different columns is discussed. It has been suggested that future clinical labora-tories should be able routinely to analyze hundreds, or even thousands, of physiological samples for hundreds of constituents (1). At least two ap-proaches are being investigated to meet this re-quirement: (a) the development of automated, high-speed, multiple analyzers capable of analyzing a large number of samples for a single constituent or, at most, only a few constituents (2); and (b) the development of automated, high-resolution analyt-ical systems capable of analyzing a single sample for hundreds of constituents (3-10). At present, neither of these two types of systems, used sepa-rately, will meet the above requirement: the first is incapable of analyzing for hundreds of constituents, and the second cannot be used for large numbers of samples. Obviously, integration of the two systems