Calculation of retention and selectivity in reversed-phase liquid chromatography

Chromatographic activity of residual silanols of alkylsilane derivatized silica surfaces

“…In this respect, the solvophobic retention theory [27][28][29] has earned significant acceptance. Based on this solvophobic theory, Galushko has proposed a calculatory model [30] for the retention of solutes in reversed-phase HPLC that appears able to predict retention factors for various solutes on different stationary phases for RP-HPLC with fairly good accuracy [31]. Basically, the method uses the retention data of just a few solutes with known molecular properties to calculate parameters describing the separation characteristics of the reversed phase.…”

Tris(2-methyl-8-quinolinolato)iron(III) as a Novel Spectrophotometric Probe for Silanol Detection

“…Although we also examined other popular silanol tests, Engelhardt,17,18 Galushko,20 and Walters 23 tests, these tests are not sensitive to the silanol content in the silanol-controlled columns. Especially, the fluctuation of the output of the Engelhardt test was too severe to evaluate the silanol effects.…”

“…3,10 To estimate the silanol effects in practical ODS columns, numerous tests have been proposed to evaluate the silanol activity on the surface of silica-based ODS (octadecylsilyl) packing materials. 5,7,[11][12][13][14][15][16][17][18][19][20][21][22] Most of the probe compounds used for evaluating the silanol activity were small molecules containing nitrogen atoms, such as p-ethylaniline, 17,18 caffeine, 19 benzylamine, 19 aniline, 20 and so on. 23 Nitrogen atoms in these probe compounds interact with silanol groups through the ionexchange or hydrogen-bonding ability of the silanol groups.…”

Tris(2-methyl-8-quinolinolato)gallium(III) as a Fluorescent Probe for Sensitive Silanol-Testing

“…10,[17][18][19][20][21][22] Here, we compared the peak parameters of the gallium(III) complex of the present work with the silanol activities of E, 17,18 G, 20 ; silica gel, 80 -100 mesh (column chromatography grade). Fig.…”

“…5,7,[10][11][12][13][14][15][16] Most of the probe compounds are small molecules containing nitrogen atoms, because much interest has been focused on the interaction through the ion-exchange or hydrogen-bonding function to which nitrogen-containing compounds are considered to respond. 10,[17][18][19][20][21][22][23] Claessens et al 16,24,25 examined the relations between various silanol-detecting molecules containing nitrogen atoms, and found a correlation among the results of the tests. They concluded that the silanol activity was influenced by individual factors on the surface of silica-base packing materials, such as deprotonation of the silanol groups, the existence of highly acidic silanol and metal impurities, and that each silanol test evaluated the degree of silanol activity differently.…”