J. Planar Chromatogr. 9, 4-15 (1996). Description of basic principles of reflectance measurement (Kubelka-Munk Equation, inhomogeneity of absorption), calibration and evaluation (introduction, linear regression, linearized regression, two-dimensional linear regression, saturation function as calibration curve, single level calibration), errors in quantitative HPTLC analysis (systematic errors, statistical errors, reduction of errors). - HPLC and HPTLC, based on absorption and fluorescence phenomena, should be directly comparable in terms of precision and accuracy. Under certain precautions the relative standard deviation is ca. 0.6 to 1.5%, depending on the problem, if calibration and data evaluation are performed correctly.

J. Planar Chromatogr. 12, 244-254 (1999). Evaluation of a new type of radiodetector designed for digital autoradiography of TLC plates. The concept is based on the parallel avalanche detection. - TLC of lipids and steroids on silica gel with n-hexane - ether - acetic acid 65:35:1 in a horizontal glass chamber previously saturated with the same mobile phase. A second development was performed with n-hexane as eluent. Quantitation by densitometry after dipping for 30 s in 3% sulfuric acid, drying at 60°C for 15 min, and heating at 160°C for 15 min.

Part 1. Description of the method and basic possibilities. J. Planar Chromatogr. 15, 454-457 (2002). Description of the principle of a novel liquid chromatographic method, fully on-line TLC/HPTLC, which integrates the idea of the continuous development, continuous-flow TLC, and diode-array detection; including the design of the prototype apparatus, and the fundamental advantages of the novel technique. HPTLC and TLC of a test dye mixture on silica gel with dichloromethane. Detection was performed with a new TLC/HPTLC scanner with optical fibers, a special fiber interface and a diode-array detector working in the range of 197 nm to 800 nm with an average optical resolution better than 2.0 nm.

Optimization of several image-denoising techniques. Acta Chromatographica 21(3), 355-367 (2009). Different techiques for videoscan denoising are presented. Due to the charged-coupled devices (CCD) noise can be a serious problem during videoscanning, especially when scanning dark plates with weakly fluorescent spots. Optimization of several kind of filters (averaging, circular, Gaussian, Savitzky-Golay, median, Wiener, FIR) and wavelet shrinkage (twelve mother wavelets from the Daubechies, Symmlet, and Coiflet family, five decomposition levels, and soft/hard thresholding) against noise autocorrelation or mean-squared error to the reference image obtained by grabbing and averaging 256 CCD frames. The median filter provided the best results. The other filters except Gaussian and wavelet shrinkage at high decomposition level were also sufficient. The Gaussian filter and wavelet shrinkage at low decomposition level could not be recommended.

(Quantitative evaluation of thin-layer chromatograms. Collection of papers. Supplements 2, 3, 4 and 5.) Loose leaflet collection of TLC procedures from the literature. A detailed summary of each original paper is given, containing: clean-up and preparation of samples, preparation of standard solutions, sample application details, chromatographic conditions, conditions for in-situ measurement, evaluation and results. Addition to part 1, 1982.

J. Chromatogr. 365, 315-320 (1986). Description of a laser fluorometric detector for determining amino acids as dansyl derivatives after HPTLC. Photon counting for fluorescence detection (computer for data processing). Calibration curves for.isoleucine and glycine down to 5 x l0 to the minus 14 mol per spot (error less than 10 % ).

Chinese J. Nucl.Tech.(Hejishu) 10 (12), 24-28 (1987) . Description of a pneumatic position-sensitive proportional counter as a radio detector for TLC, consisting of a counter, a time-amplitude converter and a computerized data system for detection of radioactive element labeled compounds.

J. Liquid Chromatogr. 12, 907-917 (1989). Use of simplex optimization for the selection of densitometer slit width and wavelength settings to maximize the reproducibility of the determination of diphenhydramine hydrochloride and pseudoephedrine hydrochloride by TLC on silica. Simultaneous adjustment of the two densitometer parameters in a systematic manner to minimize the sum of the squares of the RSD peak areas from the spots. Rapid establishment of a single set of parameters by the method, giving peak areas with a RSD of less than 1% for each of the components in the formulation.