J. Planar Chromatogr. 27, 291-296 (2014). HPTLC of phyllanthin (1), hypophyllanthin (2), and niranthin (3) from Phyllanthus amarus on silica gel with n-hexane - ethyl acetate - glacial acetic acid 30:10:1. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) to (3) were 33, 41 and 46, respectively. Linearity was in the range of 200-1200 ng/zone for (1), 200-1000 ng/zone for (2) and 200-1000 ng/zone for (3). The intermediate/interday/intra-day precisions were below 2 % (n=6). The LOD and LOQ were 50 and 200 ng/zone for (1), 100 and 200 ng/zone for (2) and 100 and 200 ng/zone for (3), respectively. Average recoveries for (1) to (3) were 100.1 %, 98.8 % and 100.3 %, respectively.

J. Liq. Chromatogr. Relat. Technol. 37, 2915-2918 (2014). HPTLC of danofloxacin on silica gel with methanol – acetone – 1M citric acid – triethylamine 28:20:2:5. Quantitative determination by absorbance measurement at 280 nm. The hRF value for danofloxacin was 30. Linearity was in the range of 1250-3750 ng/zone. The intermediate/interday/intra-day precisions were below 1 % (n=3). The LOD and LOQ were 1.3 and 3.8 ng/zone, respectively. Recovery was in the range of 97.3-95.6 %.

J. Planar Chromatogr. 27, 166-173 (2014). HPTLC of racemic mixtures of zopiclone and ofloxacin and their enantiomers eszopiclone (1) and levofloxacin (2), respectively, on silica gel with ethanol - acetonitrile - glacial acetic acid - diethylamine - water containing 50 mg hydroxy propyl-beta-cyclodextrin 4:2:3:1:1, pH 4, for zopiclone and ethanol - acetonitrile - glacial glacial acetic acid - diethylamine - water containing 30 mg hydroxy propyl-beta-cyclodextrin 4:4:3:2:1, pH 4.5, for ofloxacin. Quantitative determination by absorbance measurement at 304 and 330 nm for (1) and (2), respectively. Linearity was in the range of 1-4 μg/zone for (1) and 2-7 μg/zone for (2). The intermediate/interday/intra-day precisions were below 2 % (n=3). The LOD and LOQ were 154 and 466 ng/zone for (1) and 351 and 1095 ng/zone for (2), respectively. Average recovery was 101.8 % for (1) and 101.5 % for (2).

J. Chromatogr. Sci. 53 (5), 816-823 (2015). HPTLC of ursolic acid, betulinic acid, stigmasterol and lupeol in Shankhpushpi botanicals on silica gel in a twin-trough glass chamber with petroleum ether - ethyl acetate - toluene 7:2:1, detection by spraying with anisaldehyde reagent. Densitometric evaluation at 580 nm. The hRF value of ursolic acid was 21, of betulinic acid 29, of stigmasterol 33 and of lupeol 50. Linearity was between 100-600 ng/zone for all substances. Results of the analysis of real life samples: 134.2 mg/g and 146.1 mg/g ursolic acid in Clitorea ternatea (CT) and Canscora decussata (CD); 110.6 mg/g betulinic acid in Evolvulus alsinoides (EA); 92.8 mg/g, 154.9 mg/g, 31.9 mg/g and 39.2 mg/g stigmasterol in EA, Convolvulus pluricaulis, CT and CD; 30.1 mg/g lupeol in CT.

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.

Phytochem. Anal. 28, 125-131 (2017). HPTLC of the dried fractions of Morus alba wood on silica gel with dichloromethane – methanol 22:3, and to achieve better resolution for the high activity fractions with dichloromethane – methanol 83:17. Qualitative determination under UV 254 and 366 nm and detection with sulfuric acid reagent. Partial least squares-regression was performed to discover the substances that were most correlated to bioactivity.

J. AOAC Int. 3, 686-694 (2018). HPTLC of 11 chemical dyes, namely, Sudan I (1), II (2), III (3), and IV (4); 808 Scarlet (5); Sudan Red 7B (6); malachite green (7); Basic Orange 2 (8); auramine (9); Orange II (10); and erythrosine (11) in traditional Chinese medicine raw materials and Chinese patent medicines on silica gel with cyclohexane – trichloromethane 7:3 saturated with ammonia vapor for the separation of (1) to (8). The plate was developed a second time in the same direction with ethyl acetate – alcohol – water – aqueous ammonia 16:4:2:1 for (9) to (11). Quantitative evaluation by densitometry from 200 to 700 nm. The hRf values for (1) to (11) were 74, 78, 74, 68, 44, 23, 8, 2, 56, 28 and 20, respectively. The LODs were 2 to 3 ng/zone, except for (6) 10 ng/zone. HPTLC combined with ESI-MS was assessed for proof of the effective separation of dyes and their identification in herbal matrices.

Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 62-63 (1984). OPLC (OPTLC) of amino acids on silica with chloroform - CCl4 -MEK -propanol -methanol - acetic acid 30:30:20:30:15:2. Detection by UV 366 nm. Quantification by densitometry.