J. Planar Chromatogr. 32, 447-451 (2019). HPTLC of Fritillaria cirrhosa on silica gel with ethyl acetate - methanol - ammonia solution - water 180:20:10:1. Bioautography by dipping into a 0.15 mg/mL solution of substrate Gly-Pro-p-nitroanilide hydrochloride in 50 % of ethanol, followed by ethanol removal in the hood and dipping into a 10 U/L DPP IV enzyme solution in TrisHCl buffer (pH 8.2, 70 mM), followed by incubation at 37°C for 40 min. Detection by dipping into a solution of 0.5 % sodium nitrite in 1.2 M hydrochloric acid, followed by drying slightly for 5 min and dipping into 0.05 % N-(1-naphthyl)ethylenediamine dihydrochloride solution. Further analysis by mass spectrometry using a TLC interface. The hRF value for the dipeptidyl peptidase IV inhibitor was 58.

J. Planar Chromatogr. 32, 467-474 (2019). HPTLC of quercetin in the fresh fruits of Benincasa hispida on silica gel with toluene - ethyl acetate - formic acid 25:20:1. Quantitative determination by absorbance measurement at 262 nm. The hRF value for quercetin was 39. Linearity was between 100 and 1200 ng/zone. Intermediate precision was below 2 % (n=6). The LOD and LOQ were 20 and 60 ng/zone. Recovery rate was 94.3 %.

J. Planar Chromatogr. 32, 393-400 (2019). HPTLC of quercetin (1) and resveratrol (2) on silica gel with toluene - ethyl acetate - formic acid 12:5:3. Quantitative determination by absorbance measurement at 286 nm. The hRF values for (1) and (2) were 41 and 46, respectively. Linearity was between 50 and 2000 ng/zone for both (1) and (2).  Intermediate precision was below 2 % (n=3). The LOD and LOQ were 27 and 122 ng/zone for (1) and 83 and 370 ng/zone for (2), respectively. Recovery rate was between 99.6 and 101.9 % for (1) and (2).

J. Planar Chromatogr. 32, 371-377 (2019). HPTLC of rutin in the fruits of Benincasa hispida on silica gel with ethyl acetate - formic acid - acetic acid - water 72:7:7:14. Quantitative determination by absorbance measurement at 268 nm. The hRF value for rutin was 36. Linearity was between 0.6 and 2.7 µg/zone. Interday and intra-day precisions were below 2 % (n=6). The LOD and LOQ were 0.1 and 0.3 µg/zone. Recovery rate was 96 %.

J. Sep. Sci. 42, 1088-1104 (2019). TLC of vicenin-2, schaftoside, isoschaftoside, isoviolanthin, apigenin-6-C-β-D-xyloside-8-C-α-L- arabinoside and rutin in Dendrobium huoshanense on silica gel with ethanol - acetic acid - butanone - acetone - water 22:10:13:5:65. Qualitative identification under UV light at 366 nm. 

J. Ethnopharmacol. 235, 361-374 (2019). HPTLC of colchicine (1) and withaferin A (2) in the polyherbal ayurvedic formulation Peedantak Vati (PV) on silica gel with chloroform - 
methanol - water - formic acid 140:13:2:4. Quantitative determination by absorbance measurement at 218 nm. The hRF values for (1) and (2) were 22 and 28, respectively. LOD and LOQ were 40 and 120 ng/zone for (1) and 120 and 240 ng/zone for (2), respectively.  

J. Liq. Chromatogr. Relat. Technol. 30, 311-319 (2019). HPTLC of marker compounds in Porana sinensis on silica gel with ethyl acetate - methanol - formic acid 12:2:1. DPPH* scavenging activity was performed by spraying with 2.54 mM 2,2′‐diphenyl‐1‐picrylhydrazyl methanol solution. Xanthine oxidase inhibitory activity was detected by dipping into a xanthine oxidase staining solution [agar: 0.1 mg/mL; EDTA (ethylenediaminetetraacetic acid): 1 mM; dipotassium hydrogen phosphate/potassium dihydrogen phosphate: 50 mM; NBT (nitro blue tetrazolium): 0.22 mg/mL; xanthine oxidase: 68 mU/mL], followed by incubation for 10 min at 38 °C in an incubation chamber and dipped again in 3 mM solution of xanthine, followed by a second incubation for 20 min at 38° C.

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).