J. Food. Biochem. 45, e13764 (2021). HPTLC of L-arabinose, D-fructose, D-fucose, D-galactose, D-glucose, D-mannose, D-rhamnose, D-xylose in the roots of Sechium edule on silica gel with chloroform - n-butanol - methanol - water - acetic acid 9:15:10:3:3. Detection by spraying with 5 % sulfuric acid in methanol containing 0.1 % orcinol, followed by heating at 80 °C for 5-10 min.

Microbiol. Res. 266, 127215 (2023). HPTLC of β-manno-oligosaccharides mannobiose (1), mannotriose (2), and mannotetrose (3) in the fermented broth of adult-associated Bifidobacterium adolescentis DSMZ 20083 on silica gel with butanol - water - acetic acid 2:1:1 overnight (12-15 h). Detection by spraying with a mixture of 1 mg/mL orcinol, 75 % ethanol and 3.2 % sulfuric acid in water, followed by heating at 100 °C for 10 min. The method was used to determine the ability of adult-associated B. adolescentis DSMZ 20083 to utilize β-manno-oligosaccharides from guar gum, locust bean gum, konjac root, and copra meal generated using GH26 endo-β-mannanase (ManB-1601).

Food Chem. 132941 (2022). HPTLC of monosaccharides glucose, galactose and rhamnose in Abroma augusta mucilage on silica gel with acetone - butanol - water 5:4:1. Detection by spraying with orcinol-sulfuric acid solution, followed by heating at 90 °C for 5 min. 

Marine Drugs 18(4), 184 (2020). A new alginate lyase (AlgSH7), isolated from marine bacterium Microbulbifer sp. strain SH1 (Alteromonadaceae), was incubated (24 h at 40 °C) with sodium alginate from brown algae (1 % in TRIS-HCl buffer, pH 9), or with related mannuronate and guluronate polymers (polyM and polyG), or with related saccharides with different polymerisation degrees (PD 1 – 4). TLC of reaction products as well as saccharides, on silica gel with n-butanol ­– acetic acid – water 3:2:2. Derivatization by spraying sulfuric acid (10 % in ethanol), followed by 5 min heating at 130 °C. The enzyme was active only on alginate and on polyM, cleaving them into oligomeric fragments (PD 2 – 4); it was inactive on polyG or on oligomers.

J. Planar Chromatogr. 35, 273-279 (2022). HPTLC of sweetener saccharin (1), acesulfame-K (2), neohesperidin (3), aspartame (4), stevioside (5), rebaudioside A (6), sucralose (7), and Na-cyclamate (8) in food samples on silica gel with ethyl acetate - methanol - acetic acid 5:1:1. Detection by dipping into the following reagent sequece, followed each by plate heating and image documentation or densitometry: 1) Primuline reagent (100 mg primuline in 20 mL water and 80 mL acetone), followed by solvent evaporation and detection at 366 nm; 2) ninhydrin reagent (0.3 g ninhydrin dissolved in 95 mL isopropyl alcohol and 5 mL glacial acetic acid), followed by heating at 120 °C for 5 min and detection at white light; 3) 2-naphthol sulfuric acid reagent (1 g 2-naphthol dissolved in 90 mL ethanol and 6 mL 50 % sulfuric acid added dropwise), followed by heating at 120 °C for 5 min and detection at white light. Quantification by absorbance measurement at 200 nm for (1), 230 nm for (2), 290 nm for (3), 500 nm for (4) to (7) and 650 nm for (8).  Linearity was between 30 and 600 ng/zone for (5) and (6) and 800 and 1600 ng/zone for (8).   

J. Planar Chromatogr. 35, 153-159 (2022). HPTLC of glucuronic acid in gum samples of Sterculia urens on silica gel with 1-propanol - water 7:3. Detection by spraying with napthoresorcinol sulfuric acid reagent, followed by heating at 105 °C for 5 min. Quantitative determination by absorbance measurement at 580 nm. The hRF value for glucuronic acid was 43. Linearity was between 300 and 700 ng/zone. Interday and intra-day precisions were below 2 % (n=3). Recovery was between 100.4 and 102.3 %.

J Chromatogr A, 1640, 461929 (2021). Study of the impact of different strains, culture media and parameters (temperature, time, rotational speed, and glucide and amino-acid supply) on the metabolite profile of bacteria. Samples were cultivation broths of Bacillus subtilis, B. licheniformis, B. pumilus and B. amyloliquefaciens, as well as their respective supernatant liquid-liquid extracts (apolar solvents only or QuEChERS method with acetonitrile and MgSO4 – NaCl mixture 4:1). HPTLC on silica gel (normal phase and RP-18), either as bands (for small volumes of extracts) or as areas for supernatants and bigger volumes of extracts. Extract areas were focused with a three-step procedure (up to 20mm with acetone, and twice with methanol); unextracted supernatants were focused twice with methanol and once with tetrahydrofuran, but the application zone of the plate had to be cut before development, due to the high matrix load. Development with ethyl acetate – methanol – water at different ratios after activation of the plate surface with magnesium chloride (33% relative humidity), evaluation in white light and UV. Detection of antibacterial compounds with Aliivibrio fischeri bioassay. Derivatization with primuline (for lipophilic substances) and diphenylamine aniline sulfuric acid reagent (for saccharides). This method allowed a fast comparison: A) of the patterns of the different strains (presence /absence and intensity of detected or antibacterial bands); B) of cultivation parameters: the number of metabolites increased with time, rotational speed (oxygen level), and at 37°C (vs. 30°C), whereas a minimal medium allowed the detection of more metabolites, due to the lower matrix load; C) of the impact of the extraction parameters: choice of the solvents (QuEChERS method had no advantage here), solvent – supernatant ratio (1:3 showed richer patterns than 1:1); D) of the HPTLC parameters used (better separation and resolution with normal phase vs. RP18 layers).

J. Pharm. Biomed. Anal. 189, 113488 (2020). Various extracts from red alga Plocamium dilatatum (Plocamiaceae), green alga Codium fragile tasmanicum (Codiaceae) and brown algae Carpoglossum confluens (1), Cystophora platylobium (2) and C. retorta (3) (Sargassaceae), Ecklonia radiata (Lessoniaceae), Hormosira banksia (Hormosiraceae), Phyllospora comosa (4) (Seirococcaceae) were separated on HPTLC silica gel with n-hexane – ethyl acetate – acetic acid 70:27:3. Detection A) for antioxidant activity by spraying with methanolic DPPH solution, followed by waiting for 30 min at room temperature; B) for steroids and terpenes with anisaldehyde - sulfuric acid solution, followed by heating for 10 min at 110°C; C) for carbohydrates and polyols with thymol - sulfuric acid, followed by heating for 15-20 min at 120°C. Image-based evaluation in white light and UV 366 nm. The most active bands were also characterized by ATR-FTIR (= attenuated total reflectance – Fourier-transformed infrared) spectroscopy.