Phytochem. Anal. 33, 115-126 (2022). HPTLC bioautography of 14 Egyptian plants on silica gel with methylene chloride - methanol 9:1 (system I) or ethyl acetate - methanol - water - glacial acetic acid 120:20:16:1 (system II). Detection by spraying with anisaldehyde/sulfuric acid reagent. Aromatase inhibitory assay was performed by dipping into 112.5 mL cofactor solution (containing 4.5 mL of 0.5 % sodium phosphate buffer, 4.5 mL NADPH regenerating system solution A and 0.9 mL NADPH regenerating system solution B and then completed to volume with distilled water), followed by incubation at 37 °C for half an hour, then re-immersed in 75 mL aromatase E/S mix (containing 120 μL aromatase enzyme, 0.03 mL DBF and 3 mL albumin dissolved in 0.075 M potassium phosphate buffer) and re-incubated for another half an hour. Enzymatic reaction was terminated by immersing plates into 2N sodium hydroxide stop solution. Active zones were observed under UV 366 nm. Calculation of the inhibition zones was performed by reciprocal iso-inhibition volume (RIV) that is based on measuring the zone pixel intensity. The hRF values for chrysin were 63 and 91 in systems I and II, respectivley. The intermediate precision was below 3 % (n=3). Linearity was between 0.1 and 0.3 μg/zone. LOD and LOQ were 80 and 206 ng/zone, respectively. Recovery was between 92.5 and 106.5 %. Two quantification methods, the peak area and RIV method were compared and the RIV method showed superiority over the peak area method with %RSD values of 0.98 and 1.49 compared with 2.86 and 3.58, respectively.

Chinese J. Food & Drug 23 (5), 411-415 (2021). Dashanzha tablet is a Chinese patent medicine with the function of appetizing and digestion, used for food accumulation caused by loss of appetite, indigestion, abdominal distension. For quality control, TLC of the petroleum ether extracts on silica gel with cyclohexane - methylene dichloride - ethyl acetate - glacial acetic acid 200:50:80:1. Detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 ℃ until the zones are visible in daylight. Identification by fingerprint comparison with the standard ursolic acid and the standard ingredient drug undergone the same procedure in parallel. Satisfactory results were achieved by using plates from different manufactures and under varying temperature and humidity conditions.

J. Spectroscopy & Spectral Anal. 41 (2), 388-394 (2021). SERS, as a fast and sensitive analytical technology, is widely employed in the fields of analytical chemistry, environmental detection and food safety. However, the real-life samples are mostly mixtures, and an accurate determination of the analytes in complex samples cannot be performed directly by using SERS. TLC as a separation technique is easy to operate, low cost, fast and high-throughput, and has been widely used in the fields of synthetic chemistry, analytical chemistry, medicinal chemistry, and food science. Further, the zones isolated by TLC are first visualized using iodine vapor coloring or fluorescence, and then combined with SERS for efficient qualification and quantitation of the zones of interest. Therefore, the technology of TLC combined with SERS (TLC/SERS) suits rightly for determination of various kinds of complex samples. Moreover, due to the small sample size and the relatively simplicity of the experimental equipment used, it is also suitable for the rapid field screening and detection of relatively complex samples. Introduction of the enhancement mechanism of SERS and the preparation of the active substrate, and demonstration of the broad prospects of TLC/SERS application in the fields of environmental pollutant analysis, food safety monitoring, traditional Chinese medicine and biomedicine identification etc by providing a set of successful application examples.

Chinese J. Ethnomed. & Ethnopharm. (10), 36-39 (2021). Huangjia Ruangan granules is a TCM preparation, which relaxes the liver and promotes blood circulation, and is used for treating liver fibrosis and early cirrhosis, spleen deficiency, liver depression and blood stasis. (A) Identification of Salvia miltiorrhiza Bge, Pueraria lobata (Willd.) Ohwi, and Paeoniae rubra root, by TLC of the methanol extracts, the control solutions lacking the three drugs, and the standards tanshinone IIA, puerarin, paeoniflorin, on silica gel first with chloroform – methanol – water 70:25:2.5 to 5 cm and then with toluene – ethyl acetate 24:1 to 8 cm; detection by spraying with 5 % vanillin in sulfuric acid – ethanol 1:200 and heating at 105 ˚C until the zones are visible in white light and UV 365 nm. (B) Identification of Astragali Radix, Panax notoginseng (Burkill) F. H. Chen ex C. H.) and Radix Bupleuri, by TLC of the methanol extracts, the control solutions lacking the three drugs and the standards astragaloside lV, notoginsenoside R1 and saikosaponin A, on silica gel with butanol – ethyl acetate – water 4:3:5 to 17 cm, detection by spraying with 2 % ethanol p-dimethylaminobenzaldehyde solution - sulfuric acid 2:3 and heating at 80 ˚C until the zones are visible, evaluation in white light and at UV 365 nm. The method was successfully applyed to identify six major ingredients in Huangjia Ruangan granules on the same plate through multi-information obtained, and proved to be simple, fast, specific, reproducible, robust and well suitable for the purpose.

J. Trad. Chinese Veterinary Med. 55 (1), 15-19 (2021). Qixingcha Keli is a TCM preparation converted from human to animal use, for the treatment of gastric stagnation in piglets and other animals. Quality control of its component (A) Crataegus L. by TLC of the ethanol extracts, the control solutions with and without Crataegus L. on silica gel with ethyl ether - chloroform - formic acid 5:5:1 to 9 cm. Detection by heating the plates at 105 ˚C for 15 min, then spraying with 0.05 % bromophenol solution (pH = 7.5) and viewing in white light. For component (B) Glycyrrhiza uralensis Fisch., TLC of the ethanol extracts, the control solutions with or without Glycyrrhiza uralensis Fisch. on silica gel containing 1 % NaOH with ethyl acetate - formic acid - glacial acetic acid - water 15:1:1:1 to 18 cm, detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 ˚C, evaluation in white light and at UV 365 nm. For (C) Uncaria rhynchophylla (Miq.) Miq. ex Havil., TLC of the ethanol extracts and the control solutions on silica gel with petroleum ether (60-90 ˚C) - propanone 3:2 to 9 cm, detection at UV 254 nm. For (D) Semen Coicis, by TLC of the ethyl acetate extracts and control solutions on silica gel with petroleum ether (60-90 ˚C) - ethyl ether - glacial acetic acid 166:34:1 to 9 cm, detection by spraying with 5 % vanillin in sulfuric acid - ethanol 1:200 and heating at 105 ˚C, detection in white light and at UV 365 nm.

J. Food Compos. Anal. 99, 103869 (2021). HPTLC of phosphatidylcholine (1), phosphatidylethanolamine (2), phosphatidylserine (3), lysophosphatidylcholine (4), and cardiolipin (5) in edible insects (crickets, migratory locusts, and silkworms) on silica gel with chloroform - methanol - 28 % ammonia 13:7:1. Detection by exposure to iodine. The hRF values for (1) to (5) were 24, 51, 13, 15 and 70, respectively. 

J. Food Compos. Anal. 93, 103616 (2020). HPTLC profile of a selected herbal dietary supplement containing seven herbal components as ingredients on the product label (capsicum, cactus, wheat, white bean, Garcinia cambogia, psyllium husk and black pepper) on silica gel with hexane - ethyl acetate 2:1. Detection by spraying with Dragendorff’s reagent or 10 % potassium hydroxide solution in ethanol for the detection of alkaloids and anthraquinones, respectively. Qualitative analysis under UV light at 254 and 366 nm. Further analysis by mass spectrometry. The method allowed the identification of contaminant species, including the hidden oleamide compound within the selected herbal product.

Food Res. Int. 147, 110455 (2021). HPTLC of extractable and non-extractable polyphenols in peels from different species of the Passifloraceae family on silica gel with ethyl acetate - toluene - formic acid - methanol 15:15:4:1. Detection by spraying with 10 % of sulfuric acid in methanol, followed by heating at 80 °C. Evaluation in UV light at 254 and 366 nm. Further analysis by direct analysis in real-time (DART)-high-resolution mass spectrometry (HRMS) analysis.