Marine Drugs 17(3), 148 (2019). Samples were ethyl acetate extracts of seagrass Amphibolis antarctica (Cymodoceaceae), and of algae: Austrophyllis harveyana (Kallymeniaceae), Carpoglossum confluens, Cystophora harveyi, C. monilifera, C. pectinata and C. subfarcinata, Myriodesma integrifolium, Sargassum lacerifolium (Sargassaceae), Codium fragile subsp. tasmanicum (Codiaceae), Ecklonia radiata (Lessoniaceae), Hypnea valida, Rhodophyllis membaneacea (Cystocloniaceae), Hormosira banksii (Hormosiraceae), Perithalia caudata (Sporochnaceae), Phyllospora comoasa, Scytothalia dorycarpa (Seirococcaceae), Plocamium dilatatum (Plocamiaceae), and epiphytic brown algae. HPTLC on silica gel (pre-washed with methanol and heated 30 min at 100 °C) with n-hexane – ethyl acetate – acetic acid 15:9:1. Derivatization by immersion: A) into anisaldehyde – sulfuric acid reagent, followed by 10 min heating at 105 °C, for the detection of steroids and terpenes; B) into DPPH• (0.2 % in methanol), followed by 30 min incubation in the dark, for the detection of antioxydants; C) into Fast Blue B solution (0.1 % in 70 % ethanol) for detection of phenols (with alkylresorcinols detected as dark purple zones on colorless background). Effect-directed analyses were performed directly on the plates. D) α-Amylase inhibition assay by immersion into enzyme solution, incubation 30 min at 37 °C, immersion into substrate solution (starch 2 % in water), incubation 20 min at 37 °C and immersion into Gram’s iodine solution for detection (inhibition zones appear blue on white background). E) Acetylcholinesterase (AChE) inhibition assay (after neutralization by immersion into phosphate buffer) by immersion into enzyme solution, incubation 30 min at 37 °C, immersion into substrate solution (α-naphthyl acetate) and into dye reagent (Fast Blue Salt B). Densitometry through automated scanning, quantification expressed as equivalents to the respective standards used for calibration curves: A) β-sitosterol (LOQ 1.6 µg/band), B) gallic acid (LOQ 60 ng/band), D) acarbose (LOQ 173 µg/band), E) donepezil (LOQ 96 µg/mL). Alkylresorcinols were detected as antioxydant in C. harveyi and C. pectinata (hRF 88), and in C. subfarcinata (hRF 72, 81, 88). Enzymatic inhibitors in C. fragile were considered as a flavone (hRF 65) and a terpenoid (hRF 77), due to their absorption curves (densitometric scan in range 200-400 nm).

J. AOAC Int. 104, 19-25 (2022). HPTLC of xipamide (1) and triamterene (2) on silica gel with toluene - methanol - ethyl chloride - acetic acid 35:10:5:1. Quantitative determination by absorbance measurement at 300 nm. The hRF values for (1) and (2) were 52 and 37, respectively. Linearity was between 0.3 and 7.0 µg/zone for (1) and 0.3 and 12.0 µg/zone for (2). Inter-day and intra-day precisions were below 2 % (n=3). The LOD and LOQ were 47 and 141 ng/zone for (1) and 75 and 228 ng/zone for (2), respectively. Mean recovery was 100.2 % for (1) and 100.8 % for (2).

J. AOAC Int. 104, 975-982 (2021). HPTLC of methionine (1) and paracetamol (2) on silica gel with butanol - dioxane - toluene - methanol 80:25:35:3. Quantitative determination by absorbance measurement at 220 nm. The hRF values for (1) and (2) were 26 and 83, respectively. Linearity was between 2 and 12 µg/zone for (1) 5 and 30 µg/zone for (2). Inter-day and intra-day precisions were below 1 % (n=3). The LOD and LOQ were 612 and 1856 ng/zone for (1) and 1525 and 4620 ng/zone for (2), respectively. Mean recovery was 101.3 % for (1) and 100.6 % for (2). 

Marine Drugs 20(2), 106 (2022). TLC was used to monitor the fractionation of hydro-methanolic extracts of Rhodophytes: Gracilaria gracilis (Gracilariaceae) (A), Porphyra sp. (Bangiaceae) (B), Spongoclonium pastorale (Ceramiaceae / Wrangeliaceae) (C); and to assess the purity of two isolated mycosporine-like amino acids: porphyra-334 and shinorine.  TLC on silica gel with n-butanol - acetic acid - water 3:1:1. Derivatization by spraying ninhydrin reagent for the detection of peptides and amino-acids; or by spraying anisaldehyde - sulfuric acid for most phytochemicals; in both cases, followed by 5 min heating at 100 °C. Visualization under white light and at 366 nm. Porphyra-334 (hRF 28) was isolated pure from (B) and (C). Shinorine (hRF 25), isolated from (A) and (B), contained a coeluting sugar (hRF 48), which was absent after further purification on solid phase extraction, and, only when isolated from (B), a coeluting peptide or amino-acid (hRF 35), which was absent after further purification on cyclodextrane column chromatography.

J. AOAC Int. 104, 1719-1725 (2021). HPTLC of diflunisal (1) and its impurity biphenyl-4-ol (2) on silica gel with toluene - acetone - acetic acid 7:13:2. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 59 and 79, respectively. Linearity was between 0.5 and 3 µg/zone for (1) and 0.3 and 1.7 µg/zone for (2). Inter-day and intra-day precisions were below 1 % (n=3). The LOD and LOQ were 131 and 398 ng/zone for (1) and 72 and 219 ng/zone for (2), respectively. Mean recovery was 100.2 % for (1) and 100.5 % for (2). 

J. AOAC Int. 104, 1430-1441 (2021). HPTLC of eight different fixed-dose combination products of aspirin (1) with ramipril (2), caffeine (3), metoprolol (4), paracetamol (5), atorvastatin (6) and simvastatin (7) on silica gel with toluene - ethyl acetate - 1 % formic acid in methanol 35:65:3. Quantitative determination by absorbance measurement at 229 nm. The hRF values for (1) to (7) were 88, 15, 34, 49, 59, 66 and 78, respectively. Linearity was between 2000 and 6000 ng/zone for (1) and (5), 100 and 300 ng/zone for (2), 600 and 1800 ng/zone for (3), 1000 and 3000 ng/zone for (4), 200 and 600 ng/zone for (6) and 800 and 2400 ng/zone for (7). Inter-day and intra-day precisions were below 2 % (n=3). The LOD and LOQ were 107 and 323 ng/zone for (1), 32 and 98 ng/zone for (2), 17 and 51 ng/zone for (3), 3 and 10 ng/zone for (4), 9 and 27 ng/zone for (5), 109 and 331 ng/zone for (7), respectively. Recovery ranged 99.2-100.8 % for (1), 99.2-100.2 % for (2), 98.2-101.3 % for (3), 99.4-100.6 % for (4), 100.2-101.4 % for (5), 98.7-101.3 % for (6) and 99.6-101.3 % for (7).

J. Liq. Chromatogr. Relat. Technol. https://doi.org/10.1080/10826076.2022.2159977 (2021). HPTLC of Ophiopogonis Radix from different habitats on silica gel with toluene - methanol - glacial acetic acid 800:50:1. Detection under UV light at 254 nm. 

J Chromatogr A, 1647, 462153 (2021). Samples were extracts of Pittosporum angustifolium leaves (Pittosporaceae), either pure or fermented 1-4 weeks in NaCl solution, as well as acarbose, gallic acid, β-sitosterol, caffeic and chlorogenic acids, as standards. HPTLC on silica gel (prewashed with methanol and dried 15 min at 105 °C) with n-hexane – ethyl acetate – acetic acid 15:9:1. Derivatization by immersion (speed 5 cm/s, time 1 s): (A) into DPPH• 0.2 % solution, to detect radical scavengers; (B) into neutralized ferric chloride (3 % in ethanol), followed by 5 min heating at 110 °C, for detection of phenolic compounds; (C) into anisaldehyde – sulphuric acid reagent, followed by 10 min heating at 110 °C, to detect terpenes and steroids. Effect-directed analysis (EDA) for α-amylase inhibition assay (D) by immersion into enzyme solution, incubation 15 min at 37 °C, immersion into substrate solution (starch 2 % in water), incubation 20 min at 37 °C and immersion into Gram’s iodine solution for detection (inhibition zones appear blue on white background). In all cases, visualization under white light. Quantification was performed on pictures using image processing software, and expressed as equivalents to the respective standards used for calibration curves: (A) and (B) gallic acid (LOQ 250 and 740 ng/band, respectively), (C) β-sitosterol (LOQ 1.5 µg/band), (D) acarbose (LOQ 8 µg/band). Zones of interest, scraped from untreated plates and washed with ethyl acetate, were submitted by ATR-FTIR analysis. An amylase inhibiting zone (hRF 85) present in all extracts was identified as fatty acid esters: ethyl palmitate in unfermented and methyl linoleate in fermented extracts. Moreover, fermented extracts contained antioxidant zones (hRF 15 – 20), identified as monomers and oligomers (including hydroxycinnamic, guaiacyl, syringyl derivatives) from decomposed lignin.