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. Chromatogr. Sci., 59 (10), 964-970 (2021). Introduction of an accurate and sensitive method for the simultaneous determination of thioctic acid, benfotiamine and cyanocobalamin in bulk powders and in their pharmaceutical formulation. TLC on silica gel with methanol - chloroform - heptane-1 - o.4 % sulfonic acid sodium salt 70:30:1. Determination by densitometric evaluation at 240 nm. The hRf values were 17, 48 and 75 for cyanocobalamin, benfotiamine and thioctic acid, respectively.

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. 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.

Anal. Bioanal. Chem. 411, 6655-6665 (2019). HPTLC of lovastatin present in lactone (1) and hydroxy acid forms (2) and mycotoxin citrinin (3) in red yeast rice on silica gel with n-hexane - acetone - 10 % acetic acid 60:40:1. Quantitative determination by absorbance measurement at 238 nm for (1) and (2) and fluorescence measurement at 313/> 400 nm for (3). The hRF values for (1) to (3) were 35, 23 and 7, respectively. Linearity was between 50 and 500 ng/zone for (1) and (2) and 5 and 50 ng/zone for (3). Intermediate precision was below 2 % (n=5). The LOD and LOQ were 10 and 50 ng/zone for (1) and (2) and 1 and 4 ng/zone for (3). Average recovery was 109.9 % for (1) to (3).

Anal. Bioanal. Chem. 411, 725-734 (2019). HPTLC of bisphenol A (1) and its nine brominated analogs, namely monobromobisphenol A (2), 2,2’-dibromobisphenol A (3), tribromobisphenol A (4), tetrabromobisphenol A (TBBPA) (5), TBBPA mono(methyl ether) (6), TBBPA mono(allyl ether) (7), TBBPA mono(2,3-dibromopropylether) (8), TBBPA bis(allyl ether) (9), TBBPA bis(2,3-dibromopropyl ether) (10) in chicken samples on silica gel with n-hexane - ethyl acetate - dichloromethane - acetic acid 25:5:5:1. Detection at UV 254 nm. Further analysis by high-performance liquid chromatography-diode array detector/triple quadrupole mass spectrometry. The hRF values for (1) to (10) were 30, 32, 33, 45, 58, 68, 69, 69, 91 and 86, respectively.  

J. Sep. Sci. 44, 530-538 (2021). HPTLC of tamsulosin (1) and tadalafil (2) in presence of their degradation products (2) and (3) on silica gel with ethyl acetate - toluene - methanol - ammonia 20:10:20:3. Quantitative determination by absorbance measurement at 280 nm. The hRF values for (1) to (4) were 55, 68, 14 and 24, respectively. Linearity was between 0.5 and 25 µg/zone for (1) and (2). Intermediate precision was below 2 % (n=3). Average recovery was 99.7 % for (1) and 100.3 % for (2).