Microbiol. Res. 268, 127295 (2023). HPTLC of cardiolipin phospholipids in the deletion mutants of two cardiolipin synthetase genes, clsA (UM270 ΔclsA) and clsB (UM270 ΔclsB), in the rhizobacterium Pseudomonas fluorescens, on silica gel with chloroform - methanol - water 14:6:1 for the first dimension and chloroform - methanol - glacial acetic acid 13:5:2 for the second dimension. The lipid composition of UM270 wt, UM270 ΔclsA and UM270 ΔclsB mutant strains was determined by labeling with [1-¹⁴C] acetate. Detection by iodine staining and radioactive membrane lipids were visualized by exposure to autoradiography film or a Phosphor Imager screen. Individual lipids were quantified using an image software.

J. Food Compos. Anal. 114, 104763 (2022). HPTLC of ergosterol in wheat, on silica gel with ethyl acetate - petroleum ether 3:2. Quantitative determination by absorbance measurement at 282 nm. The hRF value for ergosterol was 45. Linearity was between 40 and 600 ng/zone. Inter-day and intra-day precisions were below 4 % (n=6). The LOD and LOQ were 11 and 36 ng/zone. Recovery was between 103.7 and 107.7 %. 

Chinese Medicine 10, 13 (2015). Samples were root and rhizome extracts of Panax notoginseng (Araliaceae), either raw or in the form of commercial granules. Standards were ginsenosides Rg1, Rb1, Rd, Re and Rg2, notoginsenoside NR1. TLC on silica gel with chloroform – ethyl acetate – methanol – water 15:40:22:9, followed by 10 min air drying. Derivatization for ginsenosides by immersion into sulfuric acid (10 % in ice cold methanol), followed by 10 min air drying and 5 min heating at 100 °C. Quantification by densitometric fluorescence measurement (deuterium and tungstene lamp, 366 nm). For each standard the linear range was 0.05-1 mg/mL (LOQ comprised between 38 and 431 µg/µL). As NR1 and Re (ratio ca. 2:1) had almost the same hRF, they were quantified together as one substance. Multivariate analysis through hierarchical (HCA) and principal component analyses (PCA) was used to order the samples into two clusters, according to the analyte concentrations, the raw plant extracts being richer than most of the commercial products. This TLC method was compared to quantification through UPLC-PDA (Ultra-performance liquid chromatography with photo diode array), which was more sensitive (LOQ between 10 and 49 µg/µL) but did not allow the separation between Rg1 and Re (ratio ca. 6:1).

Marine Drugs 19(3), 161 (2021). Samples were a standard mix (tripalmitin, palmitic acid, cholesterol, phosphatidylcholine) and lipid-enriched extracts of zebrafish larvae (Danio rerio, Cyprinidae), that were anesthetized with tricaine after having being treated with 11 extracts of cyanobacteria strains and/or with a green fluorescent lipid analogue of fatty acids (BODIPY-C16, bore-dipyrromethene derivative). HPTLC on nano silica gel in 3 steps: 1) and 2) with chloroform – methanol – water 12:6:1 (twice up to 4 cm); 3) hexane – diethyl ether – acetic acid 160:40:3 (once up to 9 cm). Derivatization of lipids by spraying primuline solution (0.01 % in acetone – water, 3:2). Quantification based on fluorescence peak area intensity, was performed using image software on pictures taken through a green fluorescence imager. Triglycerides were decreased in the case of larvae treated with 2 extracts of Synechocystis strains (Merismopediaceae), but the levels of other lipid classes were not affected. No treatment significantly affected the incorporation of BODIPY-C16 into any of the lipid classes of the larvae.

Marine Drugs 20(12), 757 (2022). Samples were ethyl acetate macerates and diethyl ether Soxhlet extracts from invasive Caulerpa cylindracea and non-invasive C. lentillifera (Caulerpaceae), as well as caulerpine (bisindole alkaloid) as standard isolated from one of the extracts. TLC on silica gel with petroleum ether – diethyl ether 1:1. Quantitative evaluation by densitometry at 330 nm, quantification of caulerpine (hRF 41, LOD 20 ng/zone, LOQ 68 ng/zone). The concentrations of caulerpine in C. cylindracea extracts (96-112 µg/g) were higher than in C. lentillifera (0-8 µg/g).

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, 1188-1195 (2021). HPTLC of syringic acid (1) and vanillic acid (2) in the roots of Ricinus communis and aerial parts of Euphorbia hirta on silica gel with toluene - ethyl acetate - formic acid 14:5:1. Quantitative determination by absorbance measurement at 366 nm. The hRF values for (1) and (2) were 50 and 60, respectively. Linearity was between 2 and 10 µg/zone for both (1) and (2). Inter-day and intra-day precisions were below 2 % (n=3). The LOD and LOQ were 1518 and 5066 ng/zone for (1) and 331 and 1104 ng/zone for (2), respectively. Mean recovery was 99.4 % for (1) and 98.7 % for (2).