Adsorption theoretical error determination

Single-component adsorption isotherms can also be evalnated from the diffnse rear bonnd-ary recorded in FA or from the rear part of overloaded band profiles. Techniqnes snch as FA by characteristic point (FACP) and elntion by characteristic point (ECP) ntilize this approach. Their major advantages over FA and PP are the smaller amonnt of material needed and the faster determination of an isotherm. However, both FACP and ECP are only snitable for singlecomponent systems and can be nsed only when the efficiency of the chromatographic system used is at least several thousand theoretical plates. This is becanse both methods rely on the nse of an eqnation of the ideal model, and hence include a model error that becomes important at lower efficiencies. 

Sources of error in this approach arise from both experimental and theoretical grounds. Modern theories of SEC retention mechanism are based on the assumption that the size exclusion process uniquely determines the elution volume, and yet the possibility of reversible adsorption is difficult to dismiss and, where it occurs, errors in the interpretation may easily result. As a warning for the application of universal calibration methodology, Cas-sassa (29) indicates in a later paper that the quantity rj M is not a truly... 

As comprehensively reviewed by Lipson and Guillet (1), inverse gas chromatography (IGC) has been used as a convenient tool to study the thermodynamic properties of polymeric systems. Despite its wide usage, all experimental and theoretical factors in this technique are not fully understood. Loading determination, usually done by means of extraction or calcination, has been considered to be the most significant source of experimental error (2.). Other factors, such as concentration effects associated with large injection sizes, slow diffusion of solute probe molecules in the stationary phase, and adsorption of probes onto the liquid-support interface, may also af-... 

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