J. Planar Chromatogr. 27, 240-244 (2014). HPTLC of sulfide ions derivatized with 4-[p-,Ndimethylamino) phenyl]-2,6-diphenylpyrylium cations (25 μmol) in acetonitrile) on silica gel with a mixture of phosphoric buffer (pH 3.0) - propan-2-ol - acetonitrile 8:8:1. Quantitative determination by scanning and image analysis. The hRF values for thyopyrylium and the derivatization reagent were 73 and 54, respectively. Linearity was in the range of 40-500 pmol/zone. The intermediate/interday/intra-day precisions were below 2 % (n=9). The LOD and LOQ were 11 and 33 pmol/zone, respectively. Recovery was between 98 and 108 %.

J.A.O.A.C. 69, 499-503 (1986). Improvement of a spray reagent for TLC identification of uric acid: aqueous solution of ferric chloride and potassium ferricyanide, requiring neither heating nor pH control. Comparison of specificity and sensitivity to 5-10 ng of uric acid with those of other sprays. The false negative rate (at 95 % confidence interval) is 0-9.7 % for this spray compared with 0.7-18.7 % for the others.

J.Chinese Herb Med. (Zhongcaoyao) 21, 18 (1990). TLC of glycyrrhizin on silica with butanol - acetic acid water 4:1:2. Detection under UV 254 nm. Quantification by densitometry at 254 nm.

Amer. Lab. 24, 50T (1992). Discussion of parameters for visualization of hard layer TLC and HPTLC plates to change the sensitivity, color , limit of detection, or reaction speed to the advantage of the detection required.

LC-GC 13, 816-123 (1995). A review with 35 references on the use of TLC for converting substances into fluorescing derivatives using reagent-free activations, showing that by using fluorescence induction on amino-modified silica layers, fruit acids can be successfully detected, which is normally difficult.

J. Planar Chromatogr. 13, 317-320 (2000). TLC of 2-, 3-, 4-chlorophenol, 2,4-, 2,5-, 2,6-, 3,4- and 3,4-dichlorophenol, 2,4,5- and 2,4,6-trichlorophenol, catechol, resorcinol, pyrogallol, phloroglucinol on silica gel, silica gel-kieselguhr and polyamide with n-heptane - benzene - diethyl ether 1:1:1 for chlorophenols and benzene - methanol acetic acid 45:8:4 for polybasic phenols. Visualization with 16 different reagents resulted in different detectabilities on the different sorbents. Whereas the detectability of polyphenols with 100 ng is comparably good, no satisfactory visualizing reagent for chlorophenols has yet been found. Stable, fast and sensitive detection.

Chromatographia 65 (3-4), 239-243 (2007). Description of a novel TLC densitometric method for the determination of solasodine in various Solanum species (Solanaceae). Solasodine does not show UV absorption therefore TLC of an ion pair complex of solasodine with an acid dye was performed. TLC plates developed by using a solvent with an organic acid ensured in situ color development of the complex. Densitometry at 461 nm. Linearity was 79.2 - 495 ng/zone, with a correlation coefficient of 0.995. The method shows good reproducibility, specificity and accuracy (98.54 ± 2.8%), and eliminates post derivatization steps and the problem of background interference. Validation of the method and application of the method to determine solasodine content in various herb samples, herb extract and their formulations, without matrix interference observed.

J. Planar Chromatogr. 27, 328-332 (2014). HPTLC of crude extracts of micro-algae Dunaliella bioculata, Phaeodactylum tricornutum, and Scenedesmus obliquus on silica gel with dichloromethane - methanol 95:5. Data analysis of pictures digitally acquired at UV 254 nm and UV 366 nm included baseline correction, chromatogram alignment, principal component analysis (PCA) de-noising and diffusion drift correction. The workflow allowed to obtain a peak list containing hRF values, intensities and areas for statistical analysis.