J. Planar Chromatogr. 13, 414-419 (2000). OPLC of 13 benzodiazepines (alprazolam, brotizolam, carbamazepin, temazepam, chlordiazepoxide, cinolazepam, clobazam, clonazepam, diazepam, nitrazepam, midazolam, medazepam, prazepam) on HPTLC silica gel with 8 mobile phases (benzene - chloroform - nitromethane 492:313:195; chloroform - dichloromethane - methyl ethyl ketone 809:115:76; acetonitrile - chloroform - toluene 136:651:213; chloroform - ethyl acetate 825:175; acetone - chloroform-methanol 28:876:96; chloroform - dioxane - toluene 784:154:62; acetonitrile - chloroform - tetrahydrofuran 268:840:132; acetic acid - chloroform - n-butanol 95:862:43). Detection under UV; densitometry at 240 nm. According to the results Snyder's endogeneous solvent strength (Si), proton donator (Xe), proton acceptor(Xd), and dipole(Xn) parameters are not satisfactory for complete description of a solvent mixture used as mobile phase.

1: Definitions and practice in TLC. J. Planar Chromatogr. 6, 198-203 (1993). Validation of the purity of a drug substance by quantitative TLC according to the guidelines of the Committee for Proprietary Medicinal Products (CPMP, European Community). Validation parameters were selectivity, stability, linearity, range, limit of detection and quantification, accuracy, and precision.

J. Planar Chromatogr. 14, 100-108 (2001). Test of the 'error-budget model' acc. to Eurachem/Citac Guide on measurement uncertainty using the quantitative HPTLC determination of sodium glutamate in a food product as example. The TLC procedure was divided into stages each of which was evaluated. The dominant sources of uncertainty found were sample preparation, chromatographic separation, secondary chromatography, stability of instrumentation, inhomogeneous illumination, distribution of compound molecules in the stationary phase, and the relative position of spots and scanning slit, among others. The uncertainty estimated by means of the error-budget method was less than one fifth of the value obtained from the validation study.

J. Planar Chromatogr. 25, 269-276 (2012). Important steps to reduce the systematical errors in planar chromatography were described. Different aspects such as selecting the center of the plate, repairing the unwanted start chromatography by using a solvent, avoiding mobile phase interaction that may influence hRf values, improving signal integration by multi integration at mini stepwise positioning, applying statistical methods for outlier removal and data correlation of signal over substance mass were defined as important parameters to improve repeatability standard deviation.

Chromatographia 17, 640-642, (1983). A new method, aiming to eliminate systematic errors, connected with the visualization of the chromatographic spots on the investigated sorbents. TLC on cellulose with decalin-ethyl acetate 8:2. Detection by spraying with a solution of bromocresol green.

Part 1: Mixtures of solvents. J. High Resol.Chromatogr. 7, 104-106 (1984). TLC of red sudan G, indophenol blue, 4-dimethylaminobenzene on silica with chloroform - ethanol - benzene - hexane.

J. Chromatogr. 452, 377-398 (1988). Evaluation of the chromatographic properties of about 100 sterols, select steroids of plant origin and triterpenoids by TLC or argentation TLC and other techniques. Visualization of TL Chromatograms by spraying with 50% methanolic sulfuric acid and heating at 60°C. Discussion of the utility of each methodology.

J. Planar Chromatogr. 7, 406-409 (1994). Definition of three new technical terms for the characterization of mobile phases: the individual selectivity factor (Sf), the total selectivity factor (SF), and the identification probability (Ip) and explanation of these three terms; hints for application of the terms in routine laboratory work).