J. Chromatogr. A 1232, 3-18 (2012). A review on overpressured-layer chromatography (OPLC). OPLC is a separation technique that combines the advantages of conventional TLC/HPTLC with those of HPLC. Use of a special chromatoplate and a pump to increase and optimize the mobile phase flow velocity through an optional development distance in an adsorbent layer by employing the pressurized ultramicro (UM) chamber as a closed adsorbent layer chamber. Description of the versions of OPLC instruments, the character and achievement of off-line and on-line OPLC systems in analytical and preparative use. Demonstration of the unique advantages of planar-layer systems for detection, isolation and identification of new antimicrobials, antineoplastics, biopesticides and other biologically active substances as well as for studying fundamental biochemical reactions and mechanisms by BioArena which was newly developed as a complex bioautographic system.

J. AOAC Int. 96, 1167-1174 (2013). The review reports various applications of bioautography tests for determination of wide spectrum of antimicrobials. Based on two direct tests using Bacillus subtilis and Escherichia coli, the review discusses different applications for the screening of analytes in various biological samples. For example, the antibacterial activity of essential oils in conifers is estimated on the basis of the measured area of inhibition zones.

Trends Anal. Chem. 76, 60-70 (2016). The review discusses suitable analytical approaches for the analysis of counterfeit and substandard pharmaceuticals in Tanzania. The authors highlight the importance of TLC and HPTLC for the quality control of pharmaceuticals in developing countries, having a repeatability and a reproducibility of the results comparable to those obtained with HPLC.

J. Ethnopharmacol. 190, 116-141 (2016). This review discusses the progress in chemical analysis of Angelica sinensis and its preparations. The study describes TLC as a rapid separation method and qualitative analysis technology that is commonly used for routine chemical analysis of A. sinensis. The advantages of the technique as well as TLC systems using ferulic acid and ligustilide as markers were described.

Phytochemistry. 130, 22-46 (2016). The review describes 141 steroidal saponins and sapogenins from the genus Agave reported in the literature from 1970 to 2015. It is a comprehensive review of structures, methods of chemical profiling, including the application of TLC and 2D-TLC for the analysis of saponins and sapogenins, and HPTLC for the determination of hecogenin.

Innov. Food Sci. Emerg. Technol. 45, 361-381 (2018). Review of novel food processing technologies on the retention of polyphenols, including HPTLC methodologies for the study of the effect of pulse electric field treatment and microwave processing on polyphenols such as chlorogenic acid, cinnamic acid, catechin, rutin and quercetin.

J. AOAC Int. 101/5, 1285-1294 (2018). Review of the most important recent studies on antioxidants in foods and beverages, food ingredients, and dietary supplements by effect-directed analysis using TLC with DPPH* (2,2′-diphenyl-1-picrylhydrazyl radical), ABTS*+ (2,2′-azinobis(3-ethylbenzothiaazoline)-6-sulfonic acid radical cation), and β-carotene direct bioautography. Including discussion of the determination of total antioxidant activity by UV/VIS spectrometry combined offline with TLC, mostly for identification and quantification of phenolic compounds; and a dot-blot assay on TLC plate without development, for total antioxidant activity, as alternative with possible advantages compared with spectrometry.

J. Sep. Sci. 42, 415-430 (2019). Review of the application of TLC hyphenated with mass spectrometry for the analysis of low-molecular-mass solutes. Different monolithic layers and their main applications were also described, including plates with thin inorganic layers, composite silica/organic polymer layers and porous polymeric monolithic layers (thermally initiated and prepared by photopolymerization). Methods of detection in TLC-MS systems were also described as indirect and direct mass spectrometric analyses.