MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY THEORY-BASED ON CONVENTIONAL CHROMATOGRAPHY

From the definitions of retention time (t(R)) and resolution (R(s)) in conventional chromatography, two fundamental equations for the retent ion behaviour and resolution of neutral solutes are derived and proved to be valid in all cases of micellar electrokinetic capillary chromat ography (MECC). Two parameters, phase velocity ratio (P-r) and column availability (A(co)), are introduced to reveal clearly the relationshi ps and differences between MECC and conventional chromatography. The t (R) and R(s) values may be either positive or negative in MECC. A nega tive t(R) indicates that the solute migrates toward the positive elect rode and a positive t(R) toward the negative electrode. R(s) > 0 means that the solute with a smaller value of the capacity factor (k') in t he pair of solutes reaches the detector first, while R(s) < 0 means th at the elution order is the opposite. MECC can be classified into eigh t cases depending on the values of P-r for convenience of discussion. So far, MECC was usually performed in case IV and the resolution was p oorer than that in conventional chromatography for given values of the oretical plate number, selectivity and k'. However, a better resolutio n can be obtained in cases II, VI and VIII when P-r < (1 - k')/2. Case s VI, VIII and II are preferable to case IV for high resolution and sh ould be more frequently employed in the future.