J. Planar Chromatogr. 2, 8-18 (1989). A review on classical TLC of alkaloids like pyridine, piperidine and quinolizidine alkaloids; tropine and pseudotropine alkaloids; quinoline alkaloids; isoquioline alkaloids; bisbenzylisoquinoline alkaloids; indole alkaloids, steroidal alkaloids and purine alkaloids with 60 references.

J. Jap. Anal. (Bunseki) (4), 277-282 (1990). A review with 72 references on developing technology, detectors, and detecting reagents used in TLC of organic compounds.

J. Chromatogr. 531, 459-480 (1990). A review with 5 references on the TLC assay of benzodiazepines.

Biokémia, 15, 154-155 (1991). Study of the formaldehyde cycle by OPLC using off-line and on-line techniques. Separation of N-, S- and O-methylated compounds of the HCHO cycle. Review with 7 references.

Chromatogr. Sci. 55, 439-462 (1991). A review with 44 references on TLC of carbohydrates, covering sample preparation, sorbents, solvent systems, detection, and quantitative evaluation.

J. Chromatogr. 591, 1-18 (1992). A review with 32 references on several theories appropriate to the modeling of zone overlap in two-dimensional TLC and other separation techniques.

Chinese J. Pharm. Anal. (Yaowu Fenxi Zazhi) 13, 136-138 (1993). Brief introduction of methods for the quality control of crude drugs in the new-version Japan pharmacopoeia. TLC is strongly emphasized, and TLC procedures for 24 crude drugs are briefly described and discussed.

J. Chromatogr. 624, 425-437 (1992). Review with 89 references on the determination procedures, emphasizing on the so-called multimethods using TLC/immunological method, GC/MS and LC/MS. For most of these techniques, a strong trend towards lowering the level of detectability (down to the sub-ppb range) and improving accuracy and reproducibility can be established. TLC is considered to have several distinct advantages over other chromatographic methods: the possibility of analysing many samples simultaneously rather than serially, speed, etc.