J. Chromatogr. Sci. 53 (9) 1603-1610 (2015). TLC of two antidiabetic drugs, glimepiride and metformin HCl in pure and tablet form as a binary mixture, or subjected to acidic, basic, oxidative and photo-degradative stress, by using an optimized salting out stability-indicating and kinetic TLC technique (SOTLC) on silica gel with aqueous ammonium sulfate – acetonitrile 7:3. The hRf value of glimepiride was 26±2 and of metformin HCl 73±2. Quantitative determination by densitometry at 237 nm in the concentration range of 60-1400 ng/zone for both drugs. The correlation coefficient of the calibration curve was 0.996 for glimepiride and 0.997 for metformin HCl.

J. Liq. Chromatogr. Relat. Technol. 40, 287-291 (2017). HPTLC of hypericin on silica gel with ethyl acetate – water – formic acid – t-butyl methyl ether – cyclohexane 90:7:7:40:15. Chemiluminescence was used for detection by dipping into bis(2,4,6-trichlorophenyl)oxalate (TCPO) reagent for 1 s, prepared by dissolving 250 mg TCPO in 36 mL of n-butyl acetate, plus added 0.4 mL of 35 % hydrogen peroxide vigorously shaken for 20 min. A sensitive CCD camera was used to measure the chemiluminescence. The hRF value for hypercin was 27. LOD and LOQ were 440 and 690 pg/zone, respectively.

Planta Medica 82(18), 1546-1552 (2016). The fractionation of the butanol-soluble part of the methanol extract of Lysimachia ciliata was monitored through TLC on silica gel with chloroform – methanol – water 23:12:2, detection by spraying with sulfuric acid. The saponin-containing fractions were mixed and submitted to preparative TLC on silica gel (same mobile phase). Saponins, eluted with methanol from the water-sprayed layer, were analyzed by UPLC-ESI-MS/MS; two were identified as desglucoanagalloside B and anagallosaponin IV (29.1 % and 8.2 % of the saponin fraction, respectively).

tincture using thin-layer chromatography–direct bioautography and liquid chromatography–tandem mass spectrometry techniques. J. Planar Chromatogr. 30, 131-135 (2017). HPTLC direct bioautography of eriodictyol (1) and 4,4՛-dihydroxy-_x000D_
5,5՛-diisopropyl-2,2՛-dimethyl-3,6-bifenylodion (2) in Thymus vulgaris on silica gel with chloroform – diethyl ether – methanol 30:10:1. Detection by spraying with anisaldehyde sulfuric acid reagent, followed by heating at 100 °C for 5 min. Direct bioautography by dipping into cell suspensions of the following bacterial strains: Microccocus luteus, Bacillus subtilis, Staphylococcus aureus, methicillin-resistant Staphyloccocus aureus, Staphyloccocus epidermidis (Se), luminescence gene-tagged Pseudomonas syringae and naturally luminescent marine bacterium Aliivibrio fischeri. Bioactive components (1) and (2) were further identified by liquid chromatography‒tandem mass spectrometry.

J. Liq. Chromatogr. Relat. Technol. 40, 467-478 (2017). HPTLC of lisinopril (1), amlodipine (2), valsartan (3) and hydrochlorothiazide (4) in pharmaceutical formulations and in human plasma on silica gel with methanol – dichloromethane – glacial acetic acid 90:10:1. Quantitative determination by absorbance measurement at 215 nm. The hRF values for (1) to (4) were 29, 56, 67 and 75, respectively. Linearity was between 400 and 2000 ng/zone for (1), 200 and 1500 ng/zone for (2), 1000 and 7000 ng/zone for (3) and 300 and 1500 ng/zone for (4). LOD and LOQ were 83 and 252 ng/zone for (1), 54 and 164 ng/zone for (2), 156 and 474 ng/zone for (3) and 77 and 234 ng/zone for (4), respectively. The intermediate precision was <3 % (n=6). Recovery rate ranged from 99.3 to 100.9 % for (1-4).

J. Chromatogr. A 1526, 137-150 (2017). HPTLC of physalins from crude extracts of Chinese lantern (Physalis alkekengi L.) on silica gel with ethyl acetate – toluene – formic acid 35:15:1. Densitometric screening of physalins in absorption and in fluorescence mode after post-chromatographic derivatization with sulfuric acid reagent. Identification of the physalin L standard and its impurity, 2,3,25,27-tetrahydrophysalin A. Applying two successive plate pre-developments with methanol – formic acid 9:1 and methanol to avoid strong ion suppression caused by the developing solvent additive (formic acid), and to improve the sensitivity of HPTLC-MS/MS method combined with a slightly modified developing solvent ethyl acetate – toluene – formic acid 30:20:1. Non-targeted characterization of physalins from the same chromatographic zone and determination of physalin types by simultaneous hyphenation of HPTLC with a triple quadrupole and an ion trap mass analyzer. Demonstration of the performance of the HPTLC-densitometric and HPTLC–MS/MS methods for the analysis of physalins from aqueous reflux extracts. Observation of variations in physalin profiles and abundances in different parts of P. alkekengi harvested at different stages of maturity, showed that the husks are the most suitable plant part for P. alkekengi quality control.

J. Planar Chromatogr. 30, 429-439 (2017). HPTLC of physalin L in orange husks of Physalis alkekengi L. var. franchetii on silica gel with ethyl acetate – n-hexane 3:2. Detection by dipping into 2.5 % (v/v) sulfuric acid in ethanol. Qualitative determination under UV 366 nm. The hRF values for physalin L and its impurity were 61 and 51, respectively, as determined by HPTLC-MS.

J. Planar Chromatogr. 31, 213-219 (2018). HPTLC of β-sitosterol in the leaves of five Ficus species (F. carica, F. nitida, F. ingens, F. palmata, and F. vasta) on silica gel with ethyl – acetate 4:1. Detection by spraying with p-anisaldehyde reagent followed by drying. Quantitative determination by absorbance measurement at 550 nm. The hRf value for β-sitosterol was 17. Linearity was in the range of 100-1400 ng/zone. The intermediate precision was below 2 % (n=6). The LOD and LOQ were 32 and 98 ng/zone, respectively. Recovery was between 98.5 and 99.7 %.