J. Chromatogr. 471, 375-387 (1989). Presentation of a new version of OPLC using two, three or more chromatoplates during one separation (OPMLC). Separation of 50 - 100 or more samples during one development by OPMLC with several application examples. The admission of the eluent to the multi-layer system is performed by making a perforation in the chromatoplates at the eluent inlet of a suitable size and shape.

Proc. 6th Int. Symp. Instrum. Planar Chromatogr., (Interlaken 1991), Inst. Chromatogr., Bad Dürkheim, FRG, 419-426 (1991). The advantage and disadvantage of normal and sandwich chromatographic chambers are discussed. The chambers used for forced-flow planar chromatography, which can be also assigned to the basic categories, are pointed out. For the characterization of chamber saturation in different tanks a marker test dye mixture is proposed. A novel approach for the characterization of the vapor phase is given and the transfer possibilities of the mobile phase between the different chromatographic methods in fully off-line and fully on-line modes are reported.

J. Planar Chromatogr. 3, 193-195 (1990). TLC of alkaloids (lysergol, ergometrine, agroclavine, ergotamine, ergocristine, ergotaminine, ergocristinine) on silica with water - ethanol - ether 1:7:12 or acetonitrile - ethanol - toluene 17:2:1 was unsatisfactory with both normal HPTLC or OPLC; satisfying results were obtained with circular U-RPC. Quantification by densitometry (absorbance at 300 nm).

J. Planar Chromatogr. 6, 438-445 (1993). Multiple development in TLC provides a straightforward means of improving the separation capacity obtained by normal development. Maximum separation power in isocratic multiple development is obtained when the distance between the solvent entry position and the sample application position is minimized and when the solvent entry position and the solvent front are incremented at each development step. Concerning the resolution the solvent selectivity is the most important parameter. A further advantage of multiple development methods is the ease of automation and the possibility of incorporating solvent gradients into the separation strategy.

J. Planar Chromatogr. 7, 394-398 (1994). Presentation of a method for the computer-assisted selection of the mobile phase for the HPTLC separation of a synthetic intermediate of unknown composition which is based on recognition of the order of the spots by comparison both of spot areas and of data from the UV absorbance spectra of the spots, followed by use of the MOS°O (Monofactor Optimization system for HPTLC) method. Excellent agreement was obtained between predicted data and experimental results.

J. Chinese Pharm. Univ. (Zhongguo Yaoke Daxue Xuebao) 27, 159-162 (1996). Presentation of a new method based on a silica plate coupling electrophoresis and chromatography in one step development to give a bidimensional chromato-electrophoresis map. Description of the device in which a parallel electric field can be put upon the plate in vertical direction. Investigation of the relationship between horizontal migration and electric field strength.

J. Planar Chromatogr. 14, 203-207 (2001). Description of a new sandwich chamber in which the mobile phase can be applied to any part of the plate. Because the starting position of the development can be anywhere this mode was called 'half-way development'. The results obtained with mixtures of dyes are satisfactory.

Proc. Intern. Symp. on Planar Separations Plan. Chrom. 123-128 (2003). TLC by Pressurized Planar Electrochromato-graphy (PPEC) of 4-cholesten-3-one, 17a-acetoxyprogesterone, 2'acetonaphthone, benzanilide, and o-nitroaniline on RP-18 with 55% aqueous acetonitrile containing 50 mM acetate buffer at a nominal pH of 4.5. The applied potential was 6 kV, and the pressure was elevated. Details are omitted based on the current patent application and intellectual property considerations. Improved new technique.