J. Chromatogr. Sci. 57 (4), 312-322 (2019). Development of a method for simultaneous analysis of five antipsychotic and medicinally important β-carboline alkaloids (βCAs), namely, harmalol, harmaline, harmine, harmane and norharmane, by HPTLC on silica gel with chloroform - methanol - glacial acetic acid 39:11:1. Quantification by densitometry in fluorescence mode at 366 nm. The linearity range of standard βCAs was 25-250 ng/band, with r² between 0.97 and 0.99. The recovery was between 83.9 and 112.4 %, repeatability of the application 0.6-2.4 %, repeatability of measurement 1.9-3.1 % and intermediate precision 0.6-11.2 %). LOD and LOQ were 4.9-6.6 and 16.5-21.9 ng/band, respectively. The method proved to be simple, cost-effective, precise, sensitive and specific for the determination of βCAs in the herbs Fagonia schweinfurthii, Peganum harmala and Tribulus terrestris, and was useful in forensic and industrial analysis and fingerprinting of various βCAs containing herbs and drug formulations.

J. Chinese Trad. Patent Med. 40 (5), 1101-1105 (2018). For quality control of Fufang Tougucao Rongye solution, a herbal TCM drug for the treatment of fungal infection of the hand, TLC on silica gel with petroleum ether (60-90 ˚C) – ethyl acetate – formic acid 10:4:1. Detection by spraying with 10% sulfuric acid in ethanol and heating at 105 ˚C until the zones are visible. Evaluation under UV 366 nm. Identification by fingerprint comparison with the individual ingredients Phryma leptostachya L. subsp. asiatica (Hara) Kitamura and Zanthoxylum bungeanum Maxim. Comparison with HPLC fingerprint analysis. Quantification of quercetin by HPLC.

J. Planar Chromatogr. 32, 339-342 (2019). HPTLC of withaferin A (1) and withanolide A (2) in Solanum nigrum on silica gel with toluene - ethyl acetate - formic acid - ethanol 60:30:1:6. Detection by spraying with p-anisaldehyde sulfuric acid (1 mL of p-anisaldehyde solution in 2 mL of concentrated sulfuric acid and 100 mL of acetic acid). Quantitative determination by absorbance measurement at 530 nm. The hRF values for (1) and (2) were 43 and 55, respectively. 

J. Liq. Chromatogr. Relat. Technol. 42, 563-569 (2019). HPTLC of spinosin in the fruits of Ziziphus jujuba on silica gel with ethyl acetate - dichloromethane - methanol - water 18:10:15:5. Quantitative determination by absorbance measurement at 334 nm. The hRF value for spinosin was 38. Linearity was between 10 and 120 ng/mL. Intermediate precision was below 2 % (n=6). The LOD and LOQ were 12 and 35 ng/mL, respectively. Recovery rate was between 98.7 and 101.3 %. The HPTLC method provided similar reproducibility, accuracy and selectivity for the quantitative determination of spinosin compared with a HPLC method.

J. AOAC Int. 102, 1021-1026 (2019). HPTLC of reserpine (1), atropine (2) and piperine (3) in Sarpagandha Ghanvati on silica gel with toluene - ethyl acetate - diethyl amine 7:2:1. Quantitative determination by absorbance measurement at 269 nm for (1), 220 nm for (2) and 254 nm for (3), respectively. The hRF values for (1) to (3) were 57, 30 and 92, respectively. Linearity was between 200 and 600 ng/zone for (1), 1000 and 5000 ng/zone for (2) and 100 and 500 ng/zone for (3), respectively. Intermediate precision was below 1 % (n=3). The LOD and LOQ were 60 and 200 ng/zone for (1), 600 and 800 ng/zone for (2) and 20 and 10 ng/zone for (3), respectively. Recovery rate was 98.9 % for (1), 99.5 % for (2) and 99.1 % for (3). The recovery from the formulation was 90.3 %, 92.4 % and 90.0 % of the expected values of (1) to (3), respectively.

J. AOAC Int. 102, 1003-1013 (2019). HPTLC of quercetin (1) and berberine (2) in Pushyanuga Churna on silica gel with toluene - ethyl acetate - methanol - formic acid 6:6:2:1. Quantitative determination by absorbance measurement at 254 nm for (1) and 366 nm for (2). The hRF values for (1) and (2) were 63 and 24, respectively. Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 1 and 3 µg/mL for (1) and 0.05 and 0.1 µg/mL for (2), respectively. Recovery rate was between 93.5 and 100.6 % for (1) and 95.2 and 97.6 % for (2).

J. AOAC Int. 102, 1014-1020 (2019). HPTLC of asiaticoside in Centella asiatica on silica gel with toluene - ethyl acetate - methanol - glacial acetic acid 2:7:3:1. Detection by spraying with anisaldehyde sulfuric acid reagent. Quantitative determination by absorbance measurement at 595 nm. The hRF values for asiaticoside were between 43 and 47 in the standard, plant powder and marketed formulations. Linearity was between 200 and 1800 ng/zone. Intermediate precisions were below 2 % (n=6). The LOD and LOQ were 51 and 155 ng/zone. Recovery rate was between 97.7 and 105.5 %.

J. of Modern Trad. Chinese Med. 20 (8), 975-978 (2018). Panax notoginseng is a traditional Chinese medicinal herb which activates blood circulation, anti-platelet aggregation and anti-thrombosis. TLC for quality control of ginsenoside Rb1 (1), notoginsenoside R1 (2) and ginsenoside Rg1 (3) on silica gel with the lower phase of chloroform – methanol – water 13:7:2 (after standing for 12 h at below 10˚C). Detection by spraying with 10% sulfuric acid in ethanol and heating at 110 ˚C until the zones are visible, evaluation under UV 365 nm. Quantification by densitometric absorption measurement at 510 nm. Validation by investigation of the linearity ranges of 0.5-5.0 µg/zone (r=0.998) for (1), 0.5-5.01 µg/zone (r=0.999) for (2) and 0.5-4.9 µg/zone (r=0.998) for (3). The plate-to-plate precision % RSD (n=12) was 1.5 %, 1.1 % and 1.9 % for (1) to (3). Recovery from standard sample addition was 96.4 % (%RSD 1.4 %, n=6) for (1), 96.9 % (%RSD 0.9 %, n=6) for (2), and 98.9% (%RSD 1.7 %, n=6) for (3).