PLoS ONE 18(11), e0294775 (2023). Sample was an Azadirachta indica seed extract (Meliaceae). TLC on silica gel with different mobile phases: (1) diethyl ether – methanol 49:1; (2) diethyl ether – acetone 2:1; (3) isopropanol – n-hexane 11:9; (4) dichloromethane – methanol – acetic acid 95:5:1. After 30 min hot air drying,detection under UV light. The hRF values of azadirachtin A (a limonoid) were 75, 42, 44, 55, respectively. Mobile phase (1) was therefore chosen as solvent for purification of azadirachtin A and for its quantification by Fourier transform infrared spectroscopy (FTIR).

PLoS ONE 18(11), e0295012 (2023). TLC on silica gel to monitor the synthesis of 15 new camphene-based thiosemicarbazones produced by the reaction of camphene thiosemicarbazide either with benzaldehydes, or with acetophenones, or with one of the following molecules: benzophenone, cinnamic aldehyde, ethyl pyruvate, furaldehyde, menthone, pyrrole carboxaldehyde or thiophene-carboxaldehyde. Development with n-hexane – ethyl acetate 3:7 in the case of benzaldehydes, except vanillin; or 7:3 for the vanillin derivative and all others, followed by visualization of products with resublimated iodine. The aldehyde used for compound 15 is in fact vanillin.

J. Liq. Chromatogr. Relat. Technol. doi:10.1080/10826076.2023.2284707 (2023). HPTLC of iridoids, coumarins, pharmaceutical drugs, flavonoids, triterpenes, sesquiterpenes, steroids, phospholipids and cannabinoids on silica gel with three complementary developing solvents (CDS) of different strength and selectivity. Detection by spraying with Fast Blue Salt B, followed by heating at 100 °C for 3 min. Other detection by spraying with the mixture NP/PEG 1:1, followed by drying for 2 min. Machine learning was applied by evaluating three regressor algorithms for their ability to predict the RF values of 178 chemicals in the low polarity developing solvent. RF values were correlated with polarity related properties such as the octanol/water partition coefficient (SlogP) or the topological polar surface area (TPSA).

J. Planar Chromatogr. 36, 279-294 (2023). HPTLC of andrographolide (1), gallic acid (2) and quercetin (3) in polyherbal tablets on silica gel with toluene - ethyl acetate - methanol - formic acid 86:60:20:1. Quantitative determination by absorbance measurement at 247 nm. The hRF values for (1) to (3) were 38, 24 and 50, respectively. Linearity was in the range of 400-2400 ng/zone for (1) and 200-1200 ng/zone for (2) and (3). Intermediate precisions were below 1 % (n=3). LOD and LOQ were 48 and 101 ng/zone for (1), 27 and 86 ng/zone for (2) and 19 and 78 ng/zone for (3), respectively. Recovery was between 98.5 and 99.4 %.

J. Planar Chromatogr. 36, 223-235 (2023). HPTLC of stigmasterol in Hygrophila schulli on silica gel with toluene - methanol 9:1. Detection by spraying with anisaldehyde - sulfuric acid reagent, followed y heating at 105 °C for 4-5 min. Quantitative determination by absorbance measurement at 520 nm. The hRF value for stigmasterol was 47. Linearity was in the range of 100-500 ng/zone. Intermediate precisions were below 2 % (n=6). LOD and LOQ were 7 and 21 ng/zone, respectively. Recovery was between 98.9 and 99.2 %.

J. Planar Chromatogr. 36, 295-305 (2023). HPTLC of propyphenazone (1), caffeine (2) and ergotamine tartrate (3) in tablets and spiked human plasma on silica gel with methanol - ethyl acetate - glacial acetic acid 10:90:1. Quantitative determination by absorbance measurement at 210 nm. The hRF values for (1) to (3) were 84, 56 and 18, respectively. Linearity was in the range of 0.1-12 μg/zone for (1) and 0.1-10 μg/zone for (2) and (3). Intermediate precisions were below 2 % (n=3). Average recovery was 101.4 % for (1), 99.2 % for (2) and 101.1 % for (3).

J. Planar Chromatogr. 36, 237-249 (2023). HPTLC of the leaves of Ficus benghalensis on silica gel with toluene - ethyl acetate 93:7. Detection under UV light at 254 and 366 nm. Bioautography by pouring Bacillus subtilis culture over the plate, followed by incubation at 37 °C for 24 h. After incubation, 1 mL of 0.2 mg/mL p-iodonitrotetrazolium chloride was added to the bioautography plates and monitored at room temperature until a pink color developed. Zones of inhibition were selected and further analyzed by high-resolution liquid chromatography (HR-LC) and mass spectrometry (MS).

J. Planar Chromatogr. 36, 307-313 (2023). HPTLC of erlotinib in bulk and tablet formulation on silica gel with ethyl acetate - toluene - glacial acetic acid 35:15:1. Quantitative determination by absorbance measurement at 246 nm. The hRF value for erlotinib was 39. Linearity was in the range of 200-800 ng/zone. Intermediate precisions were below 1 % (n=3). LOD and LOQ were 5 and 15 ng/zone, respectively. Average recovery was 100.1 %.