Chromatogr. Res. Int. 10, 1-11 (2014). HPTLC of artemisinin of Indian Artemisia annua L. was performed on HPTLC foil silica gel with n-hexane - ethyl acetate 3:1 in a twin-trough chamber up to a migration distance of 85 mm. Detection with anisaldehyde sulphuric acid reagent followed by heating at 110 °C for 10–15 min. Quantitative determination of artemisinin by densitometry at 540 nm. The hRf value of artemisinin (pink colored) was 28. The linearity was between 400 to 2800 ng/spot with a correlation coefficient of 0.9975. The precision (%RSD) was ≤3.3% (n=3). The LOD and LOQ were 40 ng/zone and 80 ng/zone, respectively. Recoveries were between 74 and 105 % for 0.6 mg/mL. Artemisinin content was highest in the leaf extract; no artemisinin was detected in the root extract.

Shanxi J. Trad. Chinese Med. 9, 43-46 (2013). Danggui Buxue Wan pill is TCM compound for the treatment of psoriasis (blood dryness type), chronic eczema, neurodermatitis, skin pruritus and other skin diseases. For the quality control, TLC on silica gel (1) for Angelica sinensis with cyclohexane – dichloromethane – ethyl acetate – formic acid 4:1:1:0.1, detection at UV 366 nm; (2) for Fallopia multiflora (Thunb.) Harald. with the upper phase of toluene – ethyl acetate – formic acid 20:2:1, detection at UV 366 nm; (3) for Paeonia lactiflora Pall. with chloroform – ethyl acetate – methanol - formic acid 45:5:10:0.2, detection by spraying with 5% vanillin in sulfuric acid – ethanol 1:4 and heating at 105 °C until the spots were visible. All were identified by fingerprint comparison with the standard (paeoniflorin or ferulic acid) and/or the standard ingredient drug.

J. Planar Chromatogr. 28, 12-16 (2015). HPTLC of acrylic acid (as trans-cinnamic acid after labeling through a coupling reaction with iodobenzene at 60 ºC for 30 min) in water samples on silica gel with chloroform - methanol - acetic acid mixture 90:10:1. Quantitative determination by absorbance measurement at 254 nm. The hRF value for labeled acrylic acid was 47. Linearity was between 0.1 and 1 mM. The intermediate precisions were below 1.2 % (n=3). The LOD for the labeled acrylic acid was 0.1 nmol. Recoveries were in the range of 97-103 %.

J. Planar Chromatogr. 28, 300-306 (2015). HPTLC of ellagic acid (1), gallic acid (2) and methyl gallate (3) in gall of Quercus infectoria on silica gel with toluene - ethyl acetate - formic acid 12:9:4. Quantitative determination by absorbance measurement at 300 nm. The hRF values for (1) to (3) were 19, 29 and 46, respectively. Linearity was in the range of 590-1181 ng/zone for (1), 691-2114 ng/zone for (2) and 693-2078 ng/zone for (3). LOD and LOQ were 15 and 51 ng/zone for (1), 243 and 812 ng/zone for (2) and 155 and 516 ng/zone for (3), respectively. The intermediate precision was 3.5 % (n=3). Recoveries ranged between 96 and 102 % for (1), 97 and 105 % for (2) and 95 and 97 % for (3).

J. Planar Chromatogr. 28, 307-315 (2015). HPTLC of carbinoxamine (1), pholcodine (2) and ephedrine (3) in a pharmaceutical preparation on silica gel with chloroform - propanol - ammonia 60:40:1. Quantitative determination by absorbance measurement at UV 254 nm. The hRF values for (1) to (3) were 12, 30 and 42. Linearity was in the range of 0.5-9 ng/zone for (1), 1-10 ng/zone for (2) and 5-45 ng/zone for (3). LOD and LOQ were 0.1 and 0.4 ng/zone for (1), 0.2 and 0.6 ng/zone for (2) and 0.6 and 1.8 ng/zone for (3), respectively. Intra-day and inter-day precisions were below 2 % (n=3). Mean recoveries were around 101 % for (1) to (3). The HPTLC method was more simple, sensitive and economic than the HPLC method.

Rapid Commun. Mass Spectrom. 29, 474-484 (2015). The paper describes the modification of the standard Direct Analysis in Real Time mass spectrometry (DART) SVPA-3DS system for a reliable direct scanning of planar objects without the use of any internal standard. Optimization is focused on the substrate movement relative to the ion source outlet and the mass spectrometer inlet as well as substrate carrier and a special transfer tube. For the repeated DART-MS scanning along five identical deposited bands a mean precision of 2.7 % was obtained. A signal decay of 62 % was observed after five scans, which means that repeated analyses are possible at a decreasing signal intensity. After HPTLC of methyl-4-hydroxybenzoate and butyl-4-hydroxybenzoate, mean determination coefficients of 0.9937 and 0.9906 were obtained for five calibrations on five plates, respectively. The mean recovery of two control standards was 94 % with a mean repeatability of 9 % (n=5) obtained on five different plates.

J. Ethnopharmacol. 168, 50-60 (2015). HPTLC of lupeol (1) and β-sitosterol (2) in the leaves of Glycosmis pentaphylla on silica gel with methanol - toluene 1:9. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 66 and 50, respectively.

J. Planar Chromatogr. 28, 436-442 (2015). TLC of hydrocortisone acetate (1), fusidic acid (2), methyl paraben (3) and propyl paraben (4) on silica gel with methylene chloride – methanol – benzene 10:2:5. Quantitative determination by absorbance measurement at 240 nm. The hRF values for (1) to (4) were 13, 32, 49 and 59. The polynomial calibration range was between 1-15 μg/zone for (1) to (4). The intermediate precision was below 1.8 % (n=3). Recovery ranged 99.6-100.2 %.