J. Planar Chromatogr. 23, 359-364 (2010). TLC of four series of carbamates of 3-hydroxy- and 4-hydroxyphenyl-acetamides, 4-benzylpiperidine and 1-benzylpiperazine on RP-18 with mixtures of acetonitrile and water containing 45-90 % organic modifier, with chamber saturation for 2 h at ambient temperature. Detection under UV light at 254 nm. The results obtained were compared with theoretical lipophilicity calculated by use of ChemOffice, QikProp, and Pallas software.

J. Planar Chromatogr. 24, 295-300 (2011). TLC of Verbascum extracts (e. g. iridoids, and triterpene saponins) on silica gel in a horizontal chamber saturated with mobile phase for 10 min, by 2D separation with ethyl acetate - methanol - water 25 % ammonia 55:35:9:1 in the first direction and methanol - ethyl acetate - water - acetic acid 5:45:13:11 in a perpendicular direction. Detection by dipping in vanillin-sulfuric acid reagent for 1 s followed by heating for 10 min at 105 °C. The method was validated for its specifity, precision (repeatability and intermediate precision), stability, and robustness. Use of an image-processing program for the construction of an ’average’ fingerprint.

Chinese J. of Pharm. Anal. 29 (12), 2168-2179 (2009). TLC of the extracts of 11 varieties of herbal drugs and preparations on silica gel (conditioned with 1 % iodine in dichloromethane) with cyclohexane - dichloromethane - ethyl acetate - glacial acetic acid 200:50:80:1. Detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 °C. Identification of oleanolic acid and ursolic acid by comparison of the hRf values (hRf 54 for oleanolic acid and 38 for ursolic acid, respectively) with standards.

J. Planar Chromatogr. 24, 93-98 (2011). TLC of eleven phenols (2,6-dimethylphenol, phenol, 4-hydroxybenzaldehyde, 3-methylphenol, phloroglucinol, 2-methoxyphenol, 4-tert-butylphenol, 4-methoxyphenol, 3-nitrophenol, 2-aminophenol, 2,4-dichlorophenol) on RP-18 in a twin-trough chamber after saturation for 20 min at room temperature. 8 aqueous mobile phases (methanol - water 7:3 and 3:2, methanol - water - triethylamine 30:19:1, acetone - water 7:3 and 3:2, acetone - water - triethylamine 30:19:1, acetone - water - tetrahydrofuran 11:8:1, and methanol - water - acetic acid 30:19:1) and 6 non-aqueous mobile phases (acetone - n-hexane 1:4 and 3:7, acetone - n-hexane - triethylamine 9:40:1, tetrahydrofuran - n-hexane 1:4 and 3:7, tetrahydrofuran - n-hexane - triethylamine 9:40:1) were used. Detection under UV light at 254 nm. 2D TLC was performed by developing the plates in the first dimension using aqueous mobile phases and, after drying, non-aqueous mobile phases in the second dimension. The most efficient system was methanol - water - triethylamine 30:19:1 in the first direction and tetrahydrofuran - n-hexane - triethylamine 9:40:1 in the second direction.

J. Trad. Chinese Veterinary Med. 5, 53-55 (2010). TLC of stachydrine on silica gel with acetone - ethanol - hydrochloric acid 10:6:1. Detection by spraying with bismuth potassium iodide - 1 % iron(III)chloride in ethanol 5:1 and heating at 100 ºC. Identification by comparison of the hRf value and zone color with the standard. Quantification of stachydrine by densitometry at 510 nm. Precision (%RSD within plate, n = 8) was 3.7 %. Stability of measurement (%RSD within 120 min, n = 5) was 4.5 %. Linearity was in the range of 3.2-38.3 µg/zone (r=0.997, n = 6). The recovery (by standard addition) was 96.6 % with a %RSD of 2.0 % (n = 6).

Chromatographia 75 (9-10), 449-456 (2012). Proposal of application of OPLC and TLC techniques with micellar mobile phases to evaluate the lipophilicity of 21 newly synthesized 1,2,4-triazoles, compounds of potential importance in medicine or agriculture as fungicides. The separation of the compounds 1) by micellar TLC on cyano phase with buffered SDS – tetrahydrofuran 4:1 in a sandwich chamber; 2) by micellar OPLC on cyano phase with buffered SDS - tetrahydrofuran 4:1 in off-line mode; 3) by reversed-phase TLC on RP-8 phase with buffered solutions of acetonitrile and tetrahydrofuran in concentrations varied in the range of volume fraction from 0.3 to 0.7, in constant steps of 0.1. Detection by densitometric scanning at UV 200 nm, or by means of a video camera at UV 254 nm. Application also of micellar HPLC technique on RP-8 column eluted with buffered SDS - acetonitrile 4:1, whereas in OPLC and TLC, cyano phases were applied, which allowed the use of micellar effluents in planar chromatography measurements. Determination of the micellar parameters log km and comparison with extrapolated R M0 values determined from reversed-phase TLC experimental data, as well as with log P values (Alog Ps, AClog P, Alog P, Mlog P, KowWin, xlog P2 and xlog P3) calculated from molecular structures of solutes tested. Application of principal component analysis (PCA) and linear regression showed the results of considerable similarity between partition and retention parameters as alternative lipophilicity descriptors, and indicated micellar chromatography as a suitable technique to study lipophilic properties of organic substances.

J. Liq. Chromatogr. Relat. Technol. 35, 1325-1335 (2012). HPTLC of tolperisone (1) and its impurities 4-methylpropiophenone (2) and piperidine (3) on silica gel with cyclohexane-1,4 - dioxane - isopropanol - ethanol 32:1:2:8 + 1 drop glacial acetic acid. Detection by dipping in a 0.3 % methanolic ninhydrin solution for 10 min, followed by heating at 105 °C for 5 min. Quantitative determination by absorbance measurement at 570 nm. The hRf values of compounds (1) to (3) were 10, 76 and 60, respectively. Linearity was in the range of 60-1500 ng/band for (1), 90-400 ng/band for (2) and 40-250 ng/band for (3). Limits of detection and quantification were 20 and 60 ng/band for (1), 30 and 90 ng/band for (2) and 20 and 40 ng/band for (3), respectively.The intermediate precisions (level 2) for (1) to (3) were 1.6 %, 2.6 % and 2.4 % (n=5), respectively. Recovery for compounds (1) to (3) was between 84.6 and 99.7 %.

J. Planar Chromatogr. 25, 534-541 (2012). TLC of anthocyanins and anthocyanidins in berry fruits on cellulose layers with hydrochloric acid - glacial acetic acid - water 10:1:3. Quantitative determination by absorbance measurement at 520 nm. The hRf values obtained for pelargonidin and cyanidin were 78 and 58, respectively. The TLC method was complementary to an HPLC method and allowed for identification of the major anthocyanidins characteristic for each berry fruit.