Influence of the organic modifier on the slope of the thin-layer chromatographic equation. J. Chromatogr. 669, 246-253 (1994). Determination of the RM values of a series of steroids. Investigation of the influence of the organic solvent in the mobile phase on the slopes of the TLC equations. Analysis of the equation correlating slopes and intercepts in different solvent systems. Proposal of a TLC method to be considered as a general procedure for the determination of lipophilicity.

Abstract G-19, IPC (2005). HPTLC for estimation of corticosterone in rat plasma on silica gel with chloroform - methanol - water 9:10:1. Quantitative determination by absorbance measurement at 245 nm. Betamethasone was employed as internal standard. The extraction of plasma with ethyl acetate gave an average recovery of >85 %. The linearity was within the range of 30-300 ng/mL with LOQ being 30 ng. The method was found to be rugged and robust.

J. Chromatogr. 350, 468-470 (1986). TLC of various steroids on silica with chloroform - methanol 10:1. Detection with 1 % solution of rubeanic acid in conc. sulfuric acid. Detection limit up to 100 ng for various types of steroids. Densitometric determination at 254 nm.

J. Planar Chromatogr. 3, 34-37 (1990). Investigation of the retention behavior of 12 steroids (cholesterol, allylestrenol, pregnanediol, progesterone, estradiol, estrone, estriol etc.) using PR-HPTLC systems with acetonitrile – methanol, acetonitrile – water, and methanol – water binary mixtures. The separation abilities of the mobile phases considered were studied using the principal component analysis method. Visualization by spraying with a mixture of 10 g copper sulfate and 5 mL o-phosphoric acid (86%) dissolved in 95 mL methanol.

J. Liq. Chromatogr. Relat. Technol. 29, 2035-2044 (2006). TLC of androsterone, epi-androsterone, dehydro-epi-androsterone, testosterone, stigmasterol, beta-sitosterol, estradiol, hydrocortisone, and cholesterol on silica gel with chloroform - acetone 17:3 and activation at 100 °C, 120 °C, 150 °C, and 200 °C during 15, 30, 60, and 120 min. Activation time temperature influenced Rf values and order of separated compunds.

J. Chromatogr. A 1490, 201-211 (2017). HPTLC for comparison of the phenolic profiles of polar extracts from Populus nigra L. (1), Populus alba L. (2) and Salix alba L. (3) buds. Five chemotypical patterns were distinguished after derivatization with Natural Products reagent and confirmed by principal component analysis. The HPTLC analysis was directly hyphenated to various microbiological and biochemical assays as well as spectrometric techniques, which directly linked to active molecules in the chromatograms. The results showed that polyvalent compounds were evident when all derivatization and activity assays were combined together. Detection of at least three antimicrobial compound zones using Aliivibrio fischeri and Bacillus subtilis bioassays and of one phyto-estrogen with the planar yeast estrogen screen in Populus buds. Detection of several inhibitors of acetyl- and butyrylcholinesterase and rabbit liver esterase in all samples. Bioactive compounds were assigned by HPTLC-MS, e.g. chrysin as selective cholinesterase inhibitor, and caffeic acid and galangin as antimicrobials in (1) and (2). The method is suitable to determine the botanical origin and quality of Populus bud extracts and propolis samples.

Trends Anal. Chem. 82, 250-267 (2016). This review describes the application of capillary electrochromatography in food safety and food quality, from the first application in 1997, including the use of TLC for sample preparation in the analysis of sterols in the oils of sunflower, canola rice bran, olive (extra virgin), soybean, corn, peanut, grapeseed, and hazelnut.

leaves. J. Planar Chromatogr. 31, 377-381 (2018). HPTLC of ursolic acid and β-sitosterol in the leaves of Paederia foetida on silica gel with toluene ‒ ethyl acetate ‒ formic acid 80:20:1. Detection by spraying with anisaldehyde–sulfuric acid reagent, followed by heating at 110 °C for 1 min. Quantitative determination by absorbance measurement at 550 nm. The hRF values for (1) and (2) were 22 and 38, respectively. Linearity was between 100 and 500 ng for (1) and (2). LOD and LOQ were 40 and 121 ng for (1) and 50 and 152 ng for (2). The intermediate precision was <2 % (n=3). Recovery ranged from 97.2 % to 99.2 % for (1) and 98.0 % to 99.2 % for (2).