J. AOAC Int. 102, 714-719 (2019). HPTLC fingerprint of the aerial parts of Isodon lophanthoides (Buch. Ham. ex D. Don) Hara (IL) on silica gel with toluene - chloroform - ethyl acetate - formic acid 30:10:10:1. Detection by spraying with 10 % sulfuric acid in ethanol, followed by heating at 105 ºC. Among the 12 bands with good resolution, four ursane-type triterpenoids were recognized as ursolic acid (hRF 61), 2α-hydroxy-12-en-28-ursolic acid (hRF 25), 2α,19α-dihydroxy-12-en-28-ursolic acid (hRF 19), and 2α-O-β-D-glucoside-12-en-28-ursolic acid (hRF 3). The method allowed to distinguish Isodon lophanthoides from its substitute, I. lophanthoides var. gerardianus and was a prospect for the quality control of I. lophanthoidis herba.

J. AOAC Int. 102, 720-725 (2019). HPTLC fingerprint of 98 batches of four commonly used traditional Chinese medicines dried tangerine peel (Chen Pi), green tangerine peel (Qing Pi), immature bitter orange fruit, and bitter orange fruit (Zhi Qiao) from two similar Citrus spp on silica gel with chloroform - methanol - water - acetic acid 26:8:2:3. Detection by spraying with 5 % aluminum chloride in ethanol, followed by examination under UV light at 366 nm. Artificial neural network analysis was applied to raw HPTLC fingerprints without any image processing and by manual image processing followed by chemometrics modeling (k-nearest neighbors and partial least-square discriminant analysis).

J. AOAC Int. 102, 726-733 (2019). HPTLC of different parts of Alpinia offcinarum on silica gel with n-hexane - ethyl acetate - acetic acid 6:1:1. Antioxidant activity analysis by spraying with methanolic 0.04 % 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical reagent, followed by densitometric detection at 535 nm. Zones were scraped from HPTLC plates and further analyzed by electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF-MS/MS). The method allowed the identification of three antioxidant compounds: (5R-hydroxy-7-(4-hydroxy-3-methoxyphenyl)-1-phenyl-3-heptanone, kaempferide, and galangal with hRF values of 21, 33 and 40, respectively.

J. Liq. Chromatogr. Relat. Technol. 42, 249-257 (2019). HPTLC of methanolic extracts from the leaves of Paulownia tomentosa on silica gel with chloroform - ethyl acetate - methanol 20:3:2. HPTLC-direct bioautography by dipping into B. subtilis cell suspension, followed by incubation at 28 °C for 2 h. Then the bioautograms were dipped into an aqueous solution of the MTT vital dye (1 mg/mL (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide), followed by incubation at 28 °C for 30 min. Further analysis by using a HPLC-DAD-MS system allowed the identification of apigenin and p-coumaric acid as highly abundant antibacterial components.

J. Liq. Chromatogr. Relat. Technol. 42, 122-127 (2019). Review of the application of TLC and HPTLC for the analysis of Licorice, the dried root and rhizome of Glycyrrhiza uralensis Fisch., Glycyrrhiza inflate Bat., or Glycyrrhiza glabra L. The authors described methods using HPLC combined with HPLC fingerprint for rapid identification of species as well as methodologies for the analysis of glabridin on silica gel and RP-18.

J. Liq. Chromatogr. Relat. Technol. 32, 41-46 (2019). HPTLC of flavonoids apigenin, luteolin, chrysin, myricetin, prunin (or naringenin 7-O-glucoside), nicotiflorin (or kaempferol 3-O-rutinoside), rutin (or quercetin 3-O-rutinoside), quercetin 3-O-glucopyranoside, luteolin 7-O-glucoside, isovitexin (or apigenin-6-C-glucoside), apigenin-7-O-glucoside, naringenin, hesperetin, flavone, kaempferide, kaempferol, naringin, hesperidin, quercetin dihydrate and quercetin in Caigua (Cyclanthera pedata Scrabs) on silica gel (1) or RP-18 (2) with ethyl acetate - water - formic acid 17:3:2 for (1) or 5 % formic acid in methanol - water 7:3 for (2). Detection by heating at 110 ºC, followed by dipping into Natural product reagent for 2 min. Qualitative identification under UV light at 254 nm and 366 nm. Flavonoids were further analyzed by HPTLC–MS/(MSⁿ). 

J. Liq. Chromatogr. Relat. Technol. 41, 15-16 (2019). HPTLC of thymine (1), uracil (2), adenine (3), cytosine (4), guanine (5) and guanosine (6) in Ganoderma lucidum and Cordyceps sinensis on silica gel with dichloromethane - methanol - formic acid 160:45:16. Quantitative determination by absorbance measurement at 254 nm. Identification of nucleobases in the samples was reconfirmed by hyphenated HPTLC-MS. The hRF values for (1) to (6) were 83, 73, 46, 32, 23 and 10, respectively. The intermediate precision was below 5 % (n=3). 

J. Planar Chromatogr. 32, 243-249 (2019). HPTLC of stigmasterol (1) and cinnamic acid (2) in Pluchea dioscoridis on silica gel with chloroform - methanol - acetic acid 93:5:2. Quantitative determination of (1) by absorbance measurement at 254 nm. Compound (2) was detected by spraying with p-anisaldehyde and quantified under UV light at 513 nm. The hRF values for (1) and (2) were 57 and 19, respectivley. Linearity was between 200 and 1400 ng/zone for (1) and (2). The intermediate precision was below 2 % (n=6). The LOD and LOQ were 39 and 117 ng for (1) and 43 and 129 ng for (2), respectively. Recovery rate was between 98.8 and 99.4 % for (1) and 98.4 and 99.0 % for (2).