In the last 20 years, high-performance liquid chromatographic methods have developed from a mild curiosity into an everyday necessity for researchers in the field of carbohydrate chemistry. Those who have worked in the field during this period remember that early h.p.1.c. systems were characterized by unstable stationary phases, troublesome injection systems, and unstable, relatively insensitive detectors. While many viewed these inadequate systems as just a passing fantasy, others continued to rapidly develop and improve them so that today scores of manufacturers market extremely useful, specialized columns and instruments for the analysis of carbohydrate compounds.
In most fields of chemistry, new analytical methods are based upon fundamental knowledge or theory generated by previous workers. This is clearly true for today's state-of-the-art h.p.1.c. methods for carbohydrate analysis. For instance, the original discovery by Roseman et al.' that neutral sugars were retained on strongly basic anion-exchange resins, was important in the eventual development of the high-performance anion-exchange chromatography systems of today. For examples of the remarkable utility of these techniques, see the articles in this issue by van Riehl and Olieman (p. 39) Cefalu et al. (p. 117) Townsend et al. (p. 21 l), Paskach et al. (p. 1), and Ammeraal et al. (p. 179).
In these papers, methods for the separation and ultrasensitive detection of monosaccharides, sugar alcohols, sugar degradation products, malto-oligosaccharides, "high mannose" oligosaccharides, and various food carbohydrates are given.
In 1953, Wheaton and Bauman' demonstrated that mixtures of electrolytes and non-electrolytes could be easily separated on cation exchangers with water as the eluent. In 1959, both Felicetta et al.3 and Jones et a1.4 demonstrated that mixtures of neutral sugars could be separated from each other on cation-exchange resins which were converted into the Ba*+ or Ca'* form. Since that time, numerous other workers have made significant contributions to the understanding and enhancement of this type of separation so that today h.p.1.c. columns packed with cation-exchange resins in a large variety of ionic forms, including Ca'+, Ag+, Pb'+, Na +, and H + , are routinely used in laboratories around the world for separation of numerous sugars, sugar derivatives, and oligosaccharides. For an example of the use of the He-form, see the paper in this issue by Hotchkiss et al. (p. 81; Figs. 4 and 5).
One of the first h.p.1.c. stationary phases used in carbohydrate separations, the