Molecules, 26 (5), 1468 (2021). Summary: Samples were fortified extracts produced with iPowder technology (involving spray-drying of a rich first extract on a new batch of the same plant) from following plants: Camellia sinensis final bud and two leaves (Theaceae), Cynara scolumus leaves and Echinacea purpurea roots (Asteraceae), Eleutherococcus senticosus roots (Araliaceae), Equisetum arvense aerial part (Equisetaceae), Eschscholzia californica aerial parts (Papaveraceae), Humulus lupulus cones (Cannabaceae), Ilex paraguariensis leaves (Aquifoliaceae), Melissa officinalis aerial parts and Rosmarinus officinalis leaves (Lamiaceae), Passiflora incarnata aerial part (Passifloraceae), Raphanus sativus var. niger roots (Brassicaceae), Ribes nigrum leaves (Grossulariaceae), Spiraea ulmaria floral tops (Rosaceae), Valeriana officinalis roots (Caprifoliaceae), Vitis vinifera leaves or pomace (Vitaceae). HPTLC on silica gel with 1) ethyl acetate – toluene – formic acid – water 16:4:3:2,  or 2) cyclohexane – ethyl acetate – formic acid 30:19:1. Detection under white light, UV 254 nm and 366 nm. Extract stability after 2 years was also checked through HPTLC. Neutralization by spraying phosphate-citrate buffer, and drying in cold air stream. Effect-directed analysis using automated piezoelectrical spraying: A) for enzymatic inhibition (acetyl-cholinesterase, glucosidase, glucuronidase, tyrosinase); B) for activity against Gram-negative bacteria (Aliivibrio fischeri bioluminescence assay). Active bands of multipotent compounds were eluted from HPTLC layers with methanol through the oval elution head of a TLC-MS interface pump, into a quadrupole-Orbitrap mass spectrometer. Full scan mass spectra (m/z 100−1000) in the positive and negative ionization modes were recorded using heated electrospray ionization (HESI, spray voltage 3.5 kV, capillary temperature 270 °C). By comparison to literature, the following compounds were assigned: caffeine, catechins, carnosol, chlorogenic acid, cynaratriol, dicaffeoylquinic acid, feruloyl quinic acid, gallic acid, linoleic and linolenic acids, oleanic or ursolic acid, rosmarinic acid.

Food Chem. 374, 131714 (2022). HPTLC of authentic samples (7 apricot and 5 pumpkin samples) and simulated adulterated products on silica gel with methanol - ethyl acetate - n-hexane 170:40:3. Fluorescence detection (FLD) at 366 nm. Carotenoids (hRF=18) were identified as chemical markers, being responsible for their differentiation in apricot and most pumpkins extracts. Partial least squares discriminant analysis (PLS-DA) proved to be a promising tool for predicting the amount of added pumpkin down to 2.5 %, with prediction errors as low as 20 %.

J. Planar Chromatogr. 35, 169-179 (2022). HPTLC of arjungenin (1) and arjunetin (2) in the bark of Terminalia arjuna on silica gel with toluene - ethyl acetate - formic acid 5:4:1. Detection by spraying with 10 % solution of sulfuric acid dissolved in methanol. Quantitative determination by absorbance measurement at 420 and 475 nm for (1) and (2). The hRF values for (1) and (2) were 43 and 67, respectively. Linearity was between 100 and 1000 ng/zone for (1) and (2). The method facilitated the detection of traces amount of adulterants in herbal products.

J. Planar Chromatogr. 35, 161-167 (2022). HPTLC of catechin in the seeds of Parkia roxburghiion silica gel with ethyl acetate - acetic acid - formic acid - water 40:4:3:4. Quantitative determination by absorbance measurement at 302 nm. The hRF value for catechin was 61. Interday and intra-day precisions were below 1 % (n=3). The LOD and LOQ were 12 and 37 ng/zone, respectively. Recovery was found in the range of 99.1-99.5 %.

J. Planar Chromatogr. 35, 139-151 (2022). HPTLC of diosgenin in Costus speciosus on silica gel with n-hexane - ethyl acetate 7:2. Detection by spraying with anisaldehyde  -sulfuric acid (0.5 mL anisaldehyde in 1 mL of 97 % sulfuric acid), followed by drying at 105 °C. Quantitative determination by absorbance measurement at 440 nm. The hRF value for diosgenin was 23. Linearity was between 0.1 and 0.7 µg/zone. The LOD and LOQ were 0.84 and 2.55 µg/zone. 

J. Planar Chromatogr. 35, 127-138 (2022). HPTLC of fresh fruit peels of some species of the genus Citrus L.: Citrus aurantium L. (bitter orange), C. unshiu Marc. (satsuma mandarin), C. reticulata Blanco (Robinson mandarin), C. sinensis L. (Washington Navel orange), C. limon Brum. (lemon), C. limetta (sweet lime), C. bergamia (bergamot), C. Medica (citron), C. paradisi Macf. (starruby grapefruit), C. maxima (pomelo) and C. maxima x C. paradisi (oroblanco) on silica gel with ethyl acetate - formic acid - acetic acid - water 100:11:11:26. Detection by dipping into a solution of NP (0.5% diphenylborinic acid aminoethyl ester in ethyl acetate), followed by dipping into a PEG (5 % PEG400 in dichloromethane). Tyrosinase inhibition analysis by dipping into 32 % ammonia, followed by drying and spraying with enzyme solution and incubation at room temperature for 10 min. DPPH radical scavenging activity by dipping into a solution of 0.05 % DPPH in methanol, followed by incubation for 30 min in darkness. 

J. Planar Chromatogr. 35, 117-125 (2022). HPTLC of gallic acid (1), piperine (2),
resveratrol (3), and quercetin (4) in Ayurvedic formulation Drakshavaleha on silica gel with ethyl acetate - toluene - glacial acetic acid - formic acid 10:10:2:1. Quantitative determination by absorbance measurement at 254 and 366 nm. The hRF values for (1) to (4) were 45, 72, 68 and 58, respectively. 

J. Planar Chromatogr. 35, 89-95 (2022). HPTLC of epimers (+)‑catechin (1) and (-)‑epicatechin (2) in Onosma bracteatum on silica gel with diisopropyl ether - ethyl acetate - formic acid 90:2:7. Detection by spraying with p-toluenesulfonic acid reagent, followed by heating at 110 °C. Quantitative determination by absorbance measurement at 280 nm. The hRF values for (1) and (2) were 47 and 37, respectively. Linearity was between 1000 and 5000 ng/zone for (1) and (2). Interday and intra-day precisions were below 2 % (n=3). The LOD and LOQ were 284 and 863 ng/zone for (1) and 183 and 611 ng/zone for (2). Average recovery was 98.9 % for (1) and 99.0 % for (2).