J Chromatogr A, 1669, 462942 (2022). Samples were medroxyprogesterone acetate (MPA) as standards and commercial drug extracts, dissolved in dichloromethane. TLC on silica gel (preactivated by 30 min heating at 120 °C) with dichloromethane – ethyl acetate 10:1, followed by 30 min drying at 120 °C. Derivatization by spraying with sulfuric acid (50 % in ethanol). Visualization in a 3D-printed chamber designed especially for this purpose, blocking extraneous light and including a smartphone holder, a fluorescent lamp and an optical density step tablet. Pictures were taken with the smartphone digital camera, after spraying (6 background images) and after 10 min heating at 120 °C (6 foreground images). In the last case, MPA appeared as black spots (hRF 16–20). Using an image processing software program: (1) one averaged background image and one averaged foreground image were created by concatenation and were split into 3 colour channels; (2) the green colour channels were corrected to remove background noise, by subtraction of an averaged darkfield image (taken on blank plate without light) and by comparison ratio to an averaged blankfield image (taken on blank plate with light); (3) the pixel values of the MPA bands were converted to optical density values through the Robard’s function, by comparison to a reference image of a theoretical optical density step tablet; (4)  furthermore, the corrected background image was subtracted from the corrected (and denoised with a Gaussian Blur) foreground image; a triangle threshold algorithm was applied on the resulting image, and was converted to a mask (white spots on black background); (5) applying the binary mask to the original corrected images (obtained in (2)), the final integrated density values of MPA spots were obtained. This method was validated for linearity range (1.25–3.75 mg/mL), for precision, for reproducibility, for robustness, and for accuracy expressed as average recovery values (101 % overall mean) by comparison of TLC results with HPLC-DAD results.

Food Chem. 133610 (2022). HPTLC of hormonal active compounds in 68 different botanicals on silica gel with ethyl acetate - toluene - formic acid - water 16:4:3:2. The plate was neutralized by spraying with citrate phosphate buffer (6 g/L citric acid monohydrate and 10 g/L disodium hydrogen phosphate in double-distilled water, adjusted to pH 12 by solid sodium hydroxide). To overcome diffusion caused by long bioassay incubation, zone fixation was achieved by coating with polyisobutyl methacrylate (0.25 % Degalan in n-hexane), followed by drying. The prepared yeast cell culture was piezoelectrically sprayed onto the plates, followed by incubation at 30 °C for 4 h. The substrate solution (2 mg 4-methyl umbelliferyl-β-D-galactopyranoside in 100 μL dimethyl sulfoxide and 3 mL citrate buffer) was piezoelectrically sprayed, followed by incubation at 37 °C for 1 h, dried, and documented by fluorescence light detection at 366 nm. The resulting NP-HPTLC–UV/Vis/FLD–pYAVAS–FLD bioassay allowed the detection of androgens, antiandrogens, false-positive antiandrogens, and synergists in complex mixtures.

J. Liquid Chrom. 9, 3461-3457 (1986). Isolation of dexamethasone sodium phosphate and betamethasone sodium phosphate after alkaline phosphatase reaction. TLC on silica with chloroform - methanol - water 180:15:1 or dichloromethane - ether - methanol -water 77:15:8:1; location under short wave UV. Quantification after extraction with ethanol by absorbance at 240 nm. Average recovery 100.56 resp. 100.46 %. Assay of unesterified steroids and identification of preservatives (e.g. methyl or propyl parabenzoates, phenol, benzylalcohol) may be carried out by the same method.

(Hungarian). Acta Pharmaceutica Hungarica 62, 82-87 (1992). TLC of intermediates of pipecuronium bromide on silica with benzene - acetone 8:2, cyclohexane - ethyl acetate 9:1, chloroform - methanol 1:1 or 6:4, benzene - ethyl acetate 7:3 or 95:5, hexane - acetone 85:15. methanol - conc. NH3 - (NH4)2CO3 2 mL + 5 mL + 0.35 g; hexane - methanol - conc. NH3 - (NH4)2CO3 2 mL + 18 mL + 2 mL + 0.14 g; acetonitrile - methanol - A. solvent - B. solvent 77,2:51.4:10:1; A. solvent = conc. NH3 - (NH4)2CO3 100 mL + 7 g, B. solvent = ammoniumchloride - water - conc. NH3 9 g + 2 mL + 50 mL; chloroform - methanol - NaI 50 mL + 50 mL + 1g. Detection with sulfuric acid and Dragendorff reagent.

J. Planar Chromatogr. 20, 91-94 (2007). Descripton of the modeling of TLC separation of androstane isomers to find the optimum mobile phase. A mathematical model was developed and tested. The model takes into account the interaction between solvents and uses a complex function for modeling. The proposed mathematical model gives results similar to those obtained by use of other optimization models, e. g. the Simplex and Prisma methods. TLC of 5alpha-androstan-3beta-ol, 5alpha-androstan-3alpha-ol, 5alpha-androstan-17beta-ol, 5beta-androstan-3alpha,17beta-diol, 5alpha-androstan-3beta,17beta-diol on silica gel in a saturated chamber using different mixtures of chloroform, acetone, and petroleum ether resulting in an optimum mobile phase composition of 55:19:26. Detection by spraying with 5 % ammonium molybdate and 5 % sulfuric acid in water and heating to 80 °C.

Hungarian Scientific Instruments 62, 1-9 (1986). Separation of amino acids and S-containing amino acids on cellulose with MEK -acetonitrile - acetic acid - water 3:4:1:2. Separation of N-methylated and N-formylated L-lysine on silica with propanol - methanol - 0.1 M aqueous Na-acetate 20:3:30, Separation of ether soluble DN amino acids on silica with chloroform - carbon tetrachloride -MEK - propanol - methanol - acetic acid 30:30:20:30:15:2. Separation of corticosteroids with acetonitrile - butyl acetate 1:1 and of trigonelline from tomato juice with propanol - methanol - 0.1 M Na-acetate. Appropriate staining reagents; densitometry by absorbance.

J. Gaoxiong Med. Sci. (Gaoxiong Yixue Kexue Zazhi) 7, 545-549 (1991). TLC of 8 glucocorticoids on silica with chloroform - dioxane - methanol 15:4:1. Detection by derivatization with (1S)-(-)-camphanic chloride using triethylamine as a catalyst.

Asian J. Chem. 20(7), 5514-5518 (2008). HPTLC of dutasteride on silica gel with toluene - ethyl acetate - acetic acid 14:6:1. Absorbance measurement at 210 nm. The method was linear in the range of 50-500 µg/µL. Recovery was 99.3-99.5 %. The method was suitable for routine quality control.