The Determination of Total Base of Serum by Ion Exchange Reactions of Synthetic Resins

Measurement of total base of blood serum supplies information indispensable for the complete description of the electrolyte balance in many physiological and pathological states. Older methods involving separate analyses of the principal cations or their conversion to sulfates, with subsequent determination of sulfate, were time-consuming, while the latter was of doubtful accuracy. More recently, electrodialysis, introduced by Keys (l), has made possible analyses of improved accuracy and speed. It has been our experience, however, as well as that of others, that electrodialysis did not always yield dependable figures for total base unless continued for 12 to 18 hours at relatively low current densities and Consolazio and Talbott (2) have questioned its accuracy when applied to t’he serum of certain hospitalized patients. Sunderman (3) has proposed the measurement of conductivity for determination of the total base of serum. His method requires the use of a statistically determined conversion factor from which individual deviations in some instances may cause significant error. The high efficiency with which adsorbents function in ion exchange appeared t’o offer the basis of a simple and rapid method for measurement of the total base of serum that would also avoid objectionable features of the existing methods. The action of synthetic resins as exchange adsorbents has already been characterized (4). Ion exchange was shown to be stoichiometric in nature and the titration of the effluent from a hydrogen exchange column was exactly equivalent to the salt concentration in the solution being treated. Two types were available. One, a cat.ion exchanger which acts by the adsorption of the cation on an insoluble resin “lattice,” with simultaneous release of hydrogen ions, is of the type formed by the condensation of aromatic hydroxysulfonic acids with formaldehyde. The other is an acid-adsorbing resin of the alkylene polyamine type. The latter splits easily hydrolyzable salts such as ammonium or ferric chlorides, but does not react appreciably with neutral salts such as sodium chloride. Its action has been thought to be that of adsorption on the resin framework of the acid formed by hydrolysis of the salt. An attempt was made to use the acid-adsorbing resin (Amberlite IR-4) by combining simultaneous