Ion-moderated partition

Binder SR, Sivorinovsky G. Measurement of urinary vanilmandelic acid and homovaniUic acid by high-performance liquid chromatography with electrochemical detection following extraction by ion-exchange and ion-moderated partition. J Chromatogr 1984 336 173-88. 

Gill, T. A. and J. W. Thompson. 1984. Rapid, automated analysis of amines in seafood by ion-moderated partition FIPLC. /. Food Sci. 49 603-606. 

One can easily conclude that under certain conditions the differences in partition constants may exert a decisive effect on SF. The effect of differences in the stability constants of the complexes is significantly reduced if the aqueous phase concentration of the uncomplexed metal ions is not much higher than that of the [ML,]" complexes. In the extreme case, when (at a moderate acidity) practically the only form of the metal in the aqueous... 

The most widely used type of HPl.C is panitiim chromatography, in which the stationary phase is a second liquid that is immiscible with the liquid mobile phase. In the past, most of the applications have been to nonionic, polar compounds of low to moderate molecular mass (usually --. TOIX)). Recently, however, methods have been developed (deriv atizatipn and ion pairing) that have e.xtended partition separations to ionic cumpound.s. 

Our examples so far have focused on neutral organic molecules such as acetic acid. The majority of priority pollutant organics of importance to TEQA are neutral molecules in water whose pH is within the 5-8 range. Before we leave the principles that underlie LLE, the answer to the question just posed is yes Consider the significant difference in versus HOAc partition constants discussed earlier. Ionic compounds have little to no tendency to partition into a moderate to nonpolar organic solvent. If, however, an ion can be converted to a neutral molecule via chemical change, this ion can exhibit a favorable K. This is accomplished in two ways chelation of metal ions and formation of ionpairs. The mathematical development of a metal chelate is discussed in this section. 

---