Food Chem. 355, 129555 (2021). HPTLC of phenolic compounds in tea extract on polyamide-precoated plastic plate with methanol - acetone - butanol - acetic acid 5:3:2:1. Detection by spraying with 1 % ferric chloride. Quantitative determination by desorption electrospray ionization mass spectrometry (DESI-MS).

Food Chem. 362, 130167 (2021). HPTLC of monosaccharides rhamnose, xylose, arabinose, mannose, glucose, galactose and sucrose in cladodes from Opuntia ficus-indica and Opuntia joconostle on silica gel with acetonitrile - 0.3 % ammonium hydroxide 17:3. Detection by dipping into thymol (0.2 %) and sulfuric acid (5 %) in methanol reagent, followed by heating at 95 °C for 2 min.

Food Chem. 362, 130206 (2021). HPTLC of 5-methyl tetrahydrofolate (1), tetrahydrofolate (2), pteroyl glutamate (3), 5-formyl tetrahydrofolate (4) and 10-formyl tetrahydrofolate (5) in legume seeds on silica gel with ethyl acetate - methanol - water - acetic acid 18:5:4:1. Detection under UV light at 254 and 366 nm. Quantitative determination by absorbance measurement at 366 nm. The hRF values for (1) to (5) were 69, 56, 43, 22 and 18, respectively. The intermediate precision was below 2 % (n=6). The LOD and LOQ were 10 and 29 ng/zone for (1), 19 and 57 ng/zone for (2), 9 and 28 ng/zone for (3), 10 and 29 ng/zone for (4) and 13 and 40 ng/zone for (5), respectively. Average recovery was 97.5 % for (1), 98.4 % for (2), 97.5 % for (3), 97.6 % for (4) and 97.8 % for (5).

Food Chem. 341, 128271 (2021). HPTLC of finger millet (Eleusine coracana L.) on silica gel with n-butanol - water - acetic acid 4:1:1. Detection by spraying with ninhydrin, followed by heating at 100 °C. Amino acid profiling under UV light at 546 nm. The hRF values for 21 standard amino acids ranged from 2 to 51.

Food Chem. 338, 128115 (2020). 2D HPTLC of tangeretin (1), 5-demethyltangeretin (2), nobiletin (3), 3′-demethylnobiletin (4), 4′-demethylnobiletin (5), 3′,4′-didemethylnobiletin (6), 5-demethylnobiletin (7), 5,3′-didemethylnobiletin (8), 5,4′-didemethylnobiletin (9), 5,3′,4′-tridemethylnobiletin (10), naringenin (11), hesperetin (12), naringin (13) and hesperidin (14) on silica gel with dichloromethane - methanol 20:1 containing 1 % acetic acid in the first direction, then the plate was rotated 90° to the right and eluted with petroleum ether - acetone 3:2. The hRF values for (1) to (12) were 53, 62, 46, 36, 38, 18, 57, 48, 51, 27, 43 and 42, respectively. Detection under UV light at 254 and 366 nm and by spraying with 1 % vanillin in ethanol with several drops of concentrated sulfuric acid; or with 3 % iron chloride dissolved in 0.5 M hydrochloric acid solution for compounds with a phenolic hydroxyl group. The LOD for (1) to (14) under 254 nm ranged from 0.5 to 2.5 mM, while 0.1 to 2.5 mM under 366 nm. Quantitative determination by surface-enhanced raman spectroscopy (SERS).

Food Chem. 351, 129211 (2021). High-throughput planar solid-phase extraction of 66 multi-class antibiotic residues in muscle tissue, cow milk and chicken eggs on silica gel with acetonitrile - methanol - ammonia 5:3:2 as first front-elution up to 85 mm followed by a second front-elution in the reverse direction up to 25 mm with acetonitrile -water - ammonia 9:7:4. Evaluation under UV 254 nm and 366 nm. Detection of macrolides by spraying with p-anisaldehyde sulfuric acid reagent (methanol - glacial acetic acid - sulfuric acid - p–anisaldehyde 420:50:26:3), followed by heating at 110°C for 3 min. Detection of penicillins by spraying with ninhydrin reagent (500 mg ninhydrin in ethanol - glacial acetic acid 23:2). Detection of lincosamines by spraying with aniline diphenylamine o-phosphoric acid reagent (2 g diphenylamine in methanol – o-phosphoric acid - aniline 90:10:1). Via simple clicks on the image, the auto TLC-MS interface automatically eluted the target zones at the trace level from the TLC plate into a Q Exactive Plus Hybrid Quadrupole-Orbitrap Mass Spectrometer.

J. Liq. Chromatogr. Relat. Technol. https://doi.org/10.1080/10826076.2021.1930556 (2021). HPTLC of patulin in apple juice on silica gel with methyl tert-butylether - n-pentane 9:5. Detection by spraying with 0.25 % methyl-benzothiazolinone hydrazone hydrochloride monohydrate in methanol, followed by heating at 105 °C. Quantification was performed using a 48-bit flatbed scanner for color measurements (in red, green, and blue). Quantification in fluorescence mode by use of a 16-bit CCD-camera and UV-366 nm illumination as well as a HPTLC DAD-scanner. The hRF value for patulin was 58. Linearity was between 5 and 800 ng/zone. The LOD and LOQ were 33 and 67 ng/zone, respectively.

Chemosphere. 90, 2157-2171 (2013). HPTLC of glycerophospholipids in liver and brain of male Atlantic cod (Gadus morhua) on silica gel (washed with methyl acetate - isopropanol - chloroform - methanol - 0.25 % KCl 25:25:25:10:9 and activated at 120 ºC for 30 min) with hexane - diethylether - acetic acid 40:10:1. Detection by spraying with 0.1 % dichlorofluorescin in 98 % methanol and 0.001 % 3,5-di-tert-4butylhydroxytoluene (BHT). Lipid classes were futher analyzed by gas chromatography with a flame ionization detector.