J. Liq. Chromatogr. Relat. Technol. 37, 2814-2828 (2014). HPTLC of arylureas and arylacetamides derivatives on RP-18 with 1-13 % water in dimethylsulfoxide (increment 3 %). Detection under UV 254 nm. A quantitative structure-retention relationship study allowed to investigate the retention behavior of these substances as well as determination of lipophilicity related to the biological activity towards dopamine D2 and 5-hydroxy-tryptamine receptors.

J. Planar Chromatogr. 27, 181-185 (2014). HPTLC of plumbagin in the root of Plumbago zeylanica on silica gel with n-butanol - chloroform - petroleum 2:3:1. Quantitative determination by absorbance measurement at 268 nm. The hRF value for plumbagin was 58. Linearity was in the range of 225-675 ng/zone. The intermediate/interday/intra-day precision were below 2 % (n=3). The LOD and LOQ were 30 and 90 ng/zone, respectively.

J. Planar Chromatogr. 27, 210-216 (2014). HPTLC of 5-hydroxy-L-tryptophan (1), 5-methyltryptamine (2), L-tryptophan (3) and melatonin (4) on silica gel with propan-2-ol - 25 % ammonia - water 8:1:1. Quantitative determination by absorbance measurement at 280 nm. The hRF values for (1) to (4) were 47, 79, 53 and 85, respectively. Linearity was in the range of 48-720 µg/zone for (1), 38-646 µg/zone for (2), 100-2000 µg/zone for (3) and 108-1737 µg/zone for (4). The intermediate/interday/intra-day precisions were below 3 % (n=5). The LOD and LOQ were 16 and 49 ng/zone for (1), 40 and 122 ng/zone for (2), 116 and 352 ng/zone for (3) and 145 and 439 ng/zone for (4). Mean recovery was between 97.4 and 100.1 % for (1) to (4).

J. Liq. Chromatogr. Relat. Technol. 37, 1805-1818 (2014). HPTLC of azithromycin dehydrate (1) and cefixime trihydrate (2) on silica gel with methanol – ethyl acetate – toluene – ammonia (30 %) 45:35:20:4. Quantitative determination (A) by absorbance measurement at 366 nm or (B) after spraying with stannic chloride reagent (40 mL chloroform and 40 mL glacial acetic acid were mixed and 5 mL of stannic chloride was slowly added) or (C) ethanolic sulfuric acid (20 mL of concentrated sulfuric acid in 80 mL of ethanol) followed by absorbance measurement at 450 nm for (B) and (C). The hRF values for (1) and (2) were 80 and 27 for (A) and (B) and 67 and 30 for (C). Due to concentrated sulfuric acid, (C) showed a slight change in hRF. Linearity for (1) was in the range of 1000-5000 ng/zone (A), 1500-5000 ng/zone (B) and 1000-6000 ng/zone (C) and for (2) was 400-2000 ng/zone (A), 1600-4000 ng/zone (B) and 800-2400 ng/zone (C). The intermediate/inter-day/intra-day precision was below 2 % (n=3). The LOD and LOQ for (1) was 85 and 257 ng/zone (A), 119 and 360 ng/zone (B) and 39 and 119 ng/zone (C) and for (2) it was 36 and 110 ng/zone (A), 194 and 588 ng/zone (B) and 69 and 208 ng/zone (C), respectively. Recovery was in the range of 98.2-102.4 % for both (1) and (2).

J. AOAC Int. 97, 99-104 (2014). HPTLC of pitavastatin calcium (1) and ezetimibe (2) on silica gel with toluene - ethyl acetate - glacial acetic acid 299:200:1. Quantitative determination by absorbance measurement at 235 nm. The hRf values for (1) and (2) were 38 and 58. Linearity was in the range of 50-600 ng/zone for (1) and (2). The intermediate/interday/intra-day precisions were below 2 % (n=3). The LOD and LOQ were 4 and 12 ng/zone for (1) and 4 and 11 ng/zone for (2), respectively. Recoveries were in the range of 98.7-100.1 % for (1) and 99.2-100.0 % for (2).

J. Liq. Chromatogr. Relat. Technol. 37, 2249-2257 (2014). HPTLC of benzyltrimethylammonium chloride (1), dodecyltrimethylammonium chloride (2), tetrabutylammonium bromide (3), and methyltrioctylammonium bromide (4) on silica gel with methanol - 5 % aqueous EDTA 7:3. Detection by spraying with Dragendroff reagent. The hRF values for (1) to (4) were 32, 43, 62 and 75, respectively.

J. Planar Chromatogr. 28, 54-60 (2015). HPTLC of bergenin in the aerial parts of Flueggea virosa on silica gel with dichloromethane – methanol 17:3. Quantitative determination by absorbance measurement at 220 nm. The hRF value of bergenin was 29. Linearity was between 100 and 800 ng/zone. The intermediate intra-day and inter-day precisions were below 2 % (n=6). The LOD and LOQ for bergenin were 18 and 53 ng/zone, respectively. Recoveries were in the range of 99-100 %.

J. Liq. Chromatogr. Relat. Tech. 37, 2989-2999 (2014). HPTLC of neutral and polar lipid content of digestive gland-gonad complex of Biomphalaria glabrata on silica gel with petroleum ether - diethyl ether - glacial acetic acid 80:20:1 for neutral lipids, and chloroform - methanol - deionized water 65:25:4 for phospholipids. Detection of neutral lipids by spraying with 5 % ethanolic phosphoric acid, followed by heating at 115 ºC for 10 min. Phospholipids were detected by spraying with 10 % cupric sulfate in 8 % phosphoric acid, followed by heating at 140 ºC for 30 min. Quantitative determination by absorbance measurement at 610 nm for neutral lipids and 370 nm for polar lipids. The hRF values of neutral lipids were 19 for cholesterol, 38 for oleic acid and 57 for triolein, whereas for polar lipids were 46 for phosphatidylcholine and 66 for phosphatidylethanolamine.