J. Chromatogr. A 1530, 185-191 (2017). Development of a new spray-on method for applying yeast cells to HPTLC plates, leading to a much higher sensitivity of the planar yeast estrogen screen (p-YES), which can serve as a highly valuable and sensitive screening tool for the detection of estrogenic compounds in various sample matrices such as water and wastewater, personal care products and foodstuff. HPTLC of sample constituents and direct detection of estrogenic compounds by spraying with yeast cells. This resulted in much sharper signals compared to those in previous publications. Satisfying results were achieved using cultures with cell densities of 1000 FAU with reduced signal broadening, thus lower LOQ for estrogenic compounds, e.g. estrone 2 pg/zone, 17β-estradiol 0.5 pg/zone, 17α-ethinylestradiol 0.5 pg/zone and estriol 20 pg/zone. Demonstration of the possibility of the method to characterize profiles of estrogenic activity of wastewater samples with high quality and reproducibility by using native samples from wastewater or even surface water directly applied on HPTLC plates without the need for prior sample treatment.

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).

(TLC chromatographic analysis for the quantitative estimation of the fecal bile acid composition). TLC of cholic acid, chenodesoxy cholic acid, desoxy cholic acid, lithocholic acid and ursodesoxy cholic acid on silica with isooctane - isopropanol - acetic acid 30:10:1 and/or isooctane - ethyl acetate - acetic acid 10:10:2. Derivatization with 2 % ethanolic solution of 2,7-dichlorofluoresceine. Densitometric quantification by fluorescence. Fiber rich polysaccharides (dietary fibers) elevate fecal bile acids and their metabolites. The possible role of this diet in relation to fecal bile acid concentration and large bowel cancer is discussed.

J.Trad.Chin.Med (Zhongguo Zhongyao Zazhi) 14, 466-468 (1989). TLC of D7- stigmastenol and fructose on silica with cyclohexane - ethyl acetate 4:1, and benzene - acetic acid - methanol 15:6:4. Quantification by densitometry (absorbance) at 540 nm and 500 nm.

Anal. Chim. Acta 275, 147-162 (1993). HPTLC of the anabolic residues in biological samples on silica with seven solvent systems in one or in two dimensions. Detection under UV 366 nm. Also, HPLC and GC/MS. Discussion of the influence of the matrix and the applied methods on the results.

Anal. Biochem. 239, 115-117 (1996). TLC of sterols on silica gel with hexane - ethyl ether - acetic acid 80:15:1. Dried plates were rehydrated for 30 sec in PBS and then incubated for 30 min in filipin suspension at 37°C in the dark. Afterwards washed 2 x 2 min in water. Spots visualized at 365 nm. Detection limit 5 ng cholesterol.

J. Chromatogr. A 1026 (1-2), 301-304 (2004) A new and simplified method for extraction of ergosterol (ergosta-5,7,22-trien-3beta-ol) from fungi in soil and litter was developed using pre-soaking extraction and paraffin oil for recovery. Recoveries of ergosterol were in the range of 94-100 % depending on the solvent to oil ratio. Extraction efficiencies equal to heat-assisted extraction treatments were obtained with pre-soaking extraction. Ergosterol was detected by TLC. Detection by fluorescence measurement, quantification limit was 8 ng. Using visual evaluation of images of TLC plates photographed in UV-light the quantification limit was 16 ng.