J. Planar Chromatogr. 18, 212-216 (2005). Retention factors on RP-18 layers corresponding to zero percent organic modifier in the aqueous mobile phase were determined for five mobile phase mixtures: methanol - water, acetone - water, acetonitrile - water, 2-propanol - water, and tetrahydrofuran - water and relationships between the retention factors obtained with different organic mobile phase modifiers were examined. A variety of partition coefficients were calculated by use of different software products and the correlation between these partition coefficients and chromatographically obtained lipophilicity was analyzed. On the basis of of correlations between retention factors and the partition coefficient log P, RP-18 with methanol - water as mobile phase was selected as the best RP-HPTLC system for determination of the octanol/water partition coefficient and thus the lipophilicity of the molecules. Visualization under UV light at 254 nm.

Part III – a study on CN adsorbent layers. J. Planar Chromatogr. 25, 471-474 (2012). TLC of 35 simple compounds with known literature lipophilicity on cyano phase with increasing mixtures of methanol - water. Detection by absorbance measurement at 254 nm. Correlation between single RM values and lipophilicity values as well as dependences between the extrapolated log kW and experimental lipophilicity was described.

J. High Resol. Chromatogr. 10, 560-563 (1987). Discussion of several methods for evaluation of separation quality in 2D-TLC using either the distance between spot centers for the pair of solutes which is the most difficult to separate in a mixture or the value of a suitable separation function as criteria of overall separation quality. Contour diagrams constructed from solvent composition and spot separation should be of value for comparing different solvent systems.

Effect of surface pH of silica. J. Chromatogr. 520, 249-256 (1990). Determination of the lipophilicities of 22 peptides by reversed-phase TLC on silica with surface pH values 2.0, 4.5, 7.5 and 9.0, using methanol as organic modifier in the concentration range 0 - 90 Vol.-%. Effects discussed: proportion of the organic modifier on the RM value of the peptides - influence of the peptide structure - surface pH of the silica on the silanophilic effect - influence of the presence of a ring structure, of the over all polarity and of the number of amino acids in the peptide.

J. Planar Chromatogr. 5, 323-333 (1992). Discussion of methods commonly used to determine the observed plate height in TLC including problems arising in experimental measurements. At present it seems reasonable to conclude that none of the reported methods provides an adequate description of the average plate height for TLC.

J. Planar Chromatogr. 8, 336 - 340 (1995). Introduction of a new model of solute retention for RPTLC with (B + AB)-type mobile phase. On the basis of theoretical assumptions physico-chemical relationships were derived for solute Rf values in RPTLC with acetonitrile - water, tetrahydrofuran - water, and acetone - water. The practical utility of the model has been demonstrated with abundant experimental results. Excellent agreement was observed between experimental and predicted Rf values for test solutes. - RPTLC of naphthalene, anthracene, phenanthrene, chrysene, and pyrene on RP-18 silica developed with ACN - water, THF - water, and acetone - water mixtures of different ratios.

J. Planar Chromatogr. 11, 383-387 (1998). The lipophilicity and specific hydrophobic surface area of 18 nonsteroidal anti-inflammatory drugs have been determined by RP TLC for subsequent studies of quantitative structure-activity relationships (QSAR). The mobile phases were mixtures of water and methanol containing 59 mM acetic acid, sodium acetate, or sodium chloride. The lipophilicity and specific hydrophobic surface area were calculated from the linear relationship between the actual RM value of the solutes and the concentration of methanol in the mobile phase. RP TLC on silica gel impregnated by overnight development in n-hexane - paraffin oil with water - methanol mixtures; the methanol concentration ranged from 0 to 35% in steps of 5%. The solute spots were revealed by their UV absorbance.

J. Planar Chromatogr. 14, 224-233 (2001). Review of findings on the susceptibility of the organic chemically bonded ligands to hydrolytic cleavage from the silica matrix for the most common TLC-type stationary phases, i.e. RP-18, RP-8, CN and DIOL. This process was induced by repeated (i.e. one-, two-, four-, and eightfold) development of these phases with mixed mobile phases comprising methanol, water, and buffers of different pH. Quantification of the extent of hydrolytic cleavage of the different ligands from the silica gel surface was basically achieved by means of Raman spectroscopy, although other analytical techniques like elemental (combustion) analysis, thermogravimetry, and differential scanning calorimetry were also employed. Also investigation of the factors influencing the efficiency of the hydrolytic cleavage.