J. Chromatogr. A 1260, 232-238 (2012). Presentation of a new RP-HPTLC method for the separation of pyrazinamide, isoniazid, rifampicin and ethambutol in a four fixed-dose combination tablet formulation by detection of pyrazinamide, isoniazid and rifampicin at UV 280 nm firstly, and then derivatization and detection of ethambutol at 450 nm after RP-plate development. Evaluation of methanol, ethanol and propan-1-ol as the modifiers to form alcohol-water mobile phases. Systematic optimization of the composition of each alcohol in the mobile phase by using the window diagramming concept to obtain the best separation. Examination of the Rf distribution of the separated compounds indicated that separation of the compounds with the mobile phase containing ethanol at the optimal fraction situated within the optimal hRf-values region of 20-80, thus ethanol was selected as the organic modifier and the optimal mobile phase composition was found to be ethanol – water - glacial acetic acid - 37 % ammonia 70:30:5:1.

J. Liq. Chromatogr. Relat. Technol. 36, 2363-2377 (2013). The impact of substituent of benzanilide moiety on retention of 14 (alkoxy-phenyl)benzamides was assessed by TLC on silica gel and aluminium oxide with various mixtures of n-pentane, benzene and acetone. The TLC method allowed for quantitative structure relationship (QSRR) studies with benzanilide derivatives.

J. Planar Chromatogr. 26, 267-273 (2013). HPTLC of glabridin in a Glycyrrhiza glabra formulation on silica gel with toluene - dichloromethane - ethyl acetate 1:1:1. Quantitative determination by absorbance measurement at 287 nm. The hRf value for glabridin was 57. Linearity was in the range of 25-500 ng/zone. LOD and LOQ were 10 and 25 ng/zone. Recovery was in the range of 97.3-103.2 %. Intermediate/interday/intra-day precision was below 2 % (n=6).

J. Planar Chromatogr. 26, 375-378 (2013). TLC of estrone, estradiol, and estriol on silica gel with chloroform - ethyl acetate - acetone 6:2:1. Detecion by dipping into (1) 10 % solution of phosphomolybdic acid (PMA) in methanol, followed by heating at 100 ºC for 10 min; (2) 0.2 % ceric ammonium sulfate in phosphoric acid, followed by heating at 110 ºC for 10 min; (3) 0.2 g manganese(II) chloride in 30 mL water, 30 mL methanol and 2 mL concentrated sulfuric acid, followed by heating at 100-120 ºC for 10-15 min; and (4) 1 g of vanillin in 25 mL of ethanol, 25 mL of distilled water, and 35 mL of ortho-phosphoric acid (85 %), followed by heating at 120-160 ºC for 5-15 min. The lowest detection limit for estrone (75 ng/zone) was achieved using (1) and (3), whereas for estradiol and estriol (both 4.7 ng per zone) by using (2).

J. Sep. Sci. 36, 2703-2708 (2013). HPTLC of biotin in Euphausia superba on silica gel with dichloromethane - 2-propanol - methanol 3:3:2 + 1 drop glacial acetic acid. Detection (1) by spraying with 0.1 - 1 % 4-(dimethylamino)cinnamaldehyde and sulfuric acid in ethanol, followed by drying for 5 min and spraying with liquid paraffin - chloroform 1:10. Alternatively, biotin was detected (2) by spraying with 0.05 % potassium permanganate. Quantitative determination by absorbance measurement at 530 nm for (1) and 400 nm for (2). The hRf value of biotin was 50. Linearity was in the range of 340-3310 ng/zone for both (1) and (2). LOD and LOQ were 50 and 90 ng/zone for (1) and 60 and 100 ng/zone for (2). Average recoveries were 99.6 % for (1) and 99.7 % for (2). Intermediate intra- and inter-day precision was below 2 % (n=3).

using a polyamide plate with nonaqueous and reversed micellar mobile phases. J. Planar Chromatogr. 26, 463-469 (2013). 2D TLC fingerprint of Helleborus thibetanus Franch on polyamide with chloroform - ethyl acetate - methanol 15:40:22 in the first dimension and isooctane - n-propyl alcohol - water 20:5:1 + 0.28 M sodium dodecyl sulfate in the second dimension, developing distances were 70 mm for both. Detection under UV 366 nm. Nine zones were detected for the identification of Helleborus thibetanus Franch.

J. Planar Chromatogr. 27, 1999-2020 (2014). HPTLC of methocarbamol in pharmaceutical mixtures with ibuprofen, paracetamol and diclofenac sodium and in the presence of its degradation product guaifenesin on silica gel with chloroform - methanol 47:3. Quantitative determination by absorbance measurement at 264 nm. A chemometric handling of the TLC peak responses involving the convolution of the derivative curves using 8-points sin x i polynomials, allowed the analysis of different mixtures of methocarbamol with enhancing of the regression parameters.

Food Chem. 156, 94-99 (2014). TLC of epigallocatechin gallate (1), gallic acid (2) and caffeine (3) on silica gel with dichloromethane - acetone - formic acid 8:7:1. Detection by dipping into 5 % methanol - sulfuric acid reagent, followed by heating at 105 °C for 3 min. Quantitative determination of (1) as gallic acid equivalents by absorbance measurement at 270 nm (epigallocatechin gallate (EPCG) was calculated and expressed as gallic acid equivalents because the EPCG standard is very expensive). The hRF values for (1) to (3) were 54, 69 and 80. Linearity was in the range of 500-5000 ng/zone for (2) and 200-2400 ng/zone for (3). The intermediate/inter-day/intra-day precisions were below 2 % (n=3). The LODs and LOQs were 400 and 500 ng/zone for (2) and 180 and 200 ng/zone for (3), respectively. Recoveries were between 94.9 and 100.0 % for (2).