J Chromatogr. A, 1652, 462377 (2021). Samples were vanilla tinctures, water − ethanol − ethyl acetate 1:1:1 extracts of vanilla-flavored food products and of natural Vanilla sp. (Orchidaceae) pods, oleoresin, paste and powders, as well as calibration standards of vanillin (1) and ethylvanillin (2). HPTLC on silica gel with n-hexane – ethyl acetate 1:1 for profiling, 3:2 for quantification. Other mobile phases were also tested and given in the supplement. Compounds (1) and (2) (hRF 68 and 82, respectively) were quantified by absorbance densitometry (at maximal wavelength 310 nm, deuterium lamp, scanning speed 10mm/s). Contents were found to be between 1 μg/g and 36 mg/g for (1) and null for (2) except in one tincture (62 µg/mL). Derivatizations performed for five assays: A) to detect radical scavengers, immersion (speed 3 cm/s, time 5 s) into DPPH• (0.5 mM in methanol), followed by drying for 90 s at room temperature and 30 s at 60 °C; B) to detect activity against Gram-negative bacteria, immersion (speed 2 cm/s, time 3 s) into Aliivibrio fischeri suspension, followed by recording the bioluminescence; C) to detect activity against Gram-positive bacteria, immersion (speed 3.5 cm/s, time 6 s) into Bacillus subtilis, followed by incubation 2 h at 37 °C, immersion in MTT solution, incubation for 30 min at 37 °C and heating for 5 min at 50 °C; D) to detect acetylcholinesterase (AChE) inhibitors, immersion (speed 2.5 cm/s, time 2 s) into AChE solution (666 units in TRIS buffer 0.05M, with bovine serum albumin 0.1 %, pH 7.8), incubation for 25 min at 37 °C and immersion into substrate solution (α-naphthyl acetate 0.1 % and Fast Blue salt B 0.18 % in ethanol – water, 1:2; E) to detect tyrosinase inhibitors, spraying with enzyme solution (400 unit/mL, in phosphate buffer 0.02 M, pH 6.8), followed by 2 min drying, immersion into substrate levodopa (18 mM in phosphate buffer, pH 6.8), 10 min incubation at room temperature and drying. For identification, zones of interest were transferred with methanol from underivatized HPTLC layer through a TLC-MS interface and a filter frit directly to a Quadrupole-Orbitrap MS (heated electrospray ionization, probe heater at 270°C, spray voltage 3.5kV, lock masses acetic acid for negative, dibutyl phthalate for positive ionization, mode full HR-MS scan in m/z range 50–750). Afterwards, the following substances assigned by MS were confirmed by using HPTLC comparison with standards: (1) and (2), vanillyl alcohol, vanillic acid, ethyl vanillyl ether, coumarin, 4-hydroxybenzoic acid, 4-methoxybenzoic acid, 4-hydroxybenzaldehyde, 4-allyl benzoic acid, oleamide, triacetin.

Nature - Sci. Rep. 11, 62 (2021). Samples were isopropylacetate – methanol 3:2 fractions of (1) n-hexane extracts of larvae of Apis mellifica carnica (Apidae) from hives exposed to different concentrations of neonicotinoid pesticide clothianidin in their food, as well as (2) worker jelly adsorbed from brood combs of the same hives on adsorptive filter strips (unused filter strip parts were kept as background control). HPTLC on silica gel with chloroform – methanol – water – ammonia 30:17:2:1 for (1), and with an 8-step gradient based on methanol, chloroform, toluene, and n-hexane for (2, see CBS 105: Optimization of an AMD 2 method for determination of stratum corneum lipids). Visualization at UV 366 nm before and after derivatization by immersion into primuline reagent (primuline 0.5 g/L in acetone – water 4:1). Furthermore, antibacterial activity of (2) was assessed by recording the bioluminescence on the HPTLC plates, neutralized after elution and immersed into Aliivibrio fischeri suspension. Semi-quantitative comparison showed that a higher exposure to clothianidin was correlated with a decrease in lipid composition as well as in antibacterial activity.

Anal. Bioanal. Chem. 412, 2633-2644 (2020). HPTLC of  cannabinol in sediment samples on silica gel with n-heptane - diethyl ether 9:1. Detection by spraying with cerium- molybdenum reagent (400 mg cerium IV sulfate and 20 g ammonium molybdate in 400 mL 10 % sulfuric acid). HPTLC plates were further analyzed by electrospray ionization mass spectrometry. The hRF value for cannabinol was 20. Linearity was between 25 and 155 ng/zone. Intermediate precision was below 5 % (n=3). The LOD and LOQ were 6 and 21 ng/zone. Average recovery was 73 %.

Foods 9(8), 1136 (2020). TLC of methanolic decoctions and ultrasonication extracts from Zingiber officinale (Zingiberaceae) rhizomes, as well as from commercial ginger formulations, on reverse-phase C18-silica gel with ethanol – water 13:7. Densitometry at 200 nm in absorbance and reflectance modes for 6-shogaol (SHO, hRF 36) and 6-gingerol (GIN, hRF 53). Standards of these vanilloid phenolics were also used for calibration; linearity was in the range of 100–700 ng for SHO and of 50–600 ng/band for GIN; interday and intra-day precisions were below 1.6 %. The LOD and LOQ was 34 and 101 ng for SHO, 17 and 51 ng for GIN, respectively. Recovery rates were 98.8–101.6 % for SHO and 99.0–101.5 % for GIN. For each extract, SHO and GIN levels were calculated, the yields after ultrasonication extraction were 10-25 % higher than with the corresponding decoctions. Comparison with other published methods (LC-MS and HPLC) showed superiority of this new method in terms of linearity range, accuracy and precision.

3 Biotech 10(8), 344 (2020). Rauvolfia serpentina (Apocynaceae) was cultivated in vitro as leaf-derived callus and as plantlet cultures obtained from tissues of nodal explants, without or with cadmium chloride as elicitor of alkaloid production. TLC of methanol – ammonia 10:1 extracts of callus and plantlet organs (leaves, stems and roots) on silica gel, along with indole alkaloids reserpine and ajmalicine in different concentrations. Development with chloroform – toluene – ethyl acetate – diethyl amine 7:7:4:1. Detection under UV light and by densitometry scanning in absorbance mode at 240 nm and 280 nm. The highest alkaloid yields were obtained for reserpine (hRF 15) in roots (191µg/g) and for ajmalicine (hRF 45) in callus (131µg/ml) when culture had been done with elicitor 0.15 mM for 6 days and 4 days, respectively (at 0.20 mM, an inhibiting effect was observed).

J. Planar Chromatogr. 20, 95-99 (2007). TLC of atrazine and simazine on silica gel with hexane - chloroform - acetone 12:5:3 with chamber saturation. Detection under UV light at 254 nm. Also quantitative evaluation. The genetic algorithm proved to be an optimization procedure which can be successfully applied to optimization of microwave-assisted extraction experiments. Application of recovery experiments from spiked soil.

Anal. Chim. Acta 624 (1), 1-15 (2008). Aminoglycosides and macrolides are important antibiotics for veterinary medicine and are widely used in the treatment of bacterial disease, and as feed additives for growth promotion. As a result the European commission set strict criteria for monitoring residues and requires testing for low levels of aminoglycosides and macrolides in foods. Therefore the development of fast, reliable, and sensitive methods for the extraction and subsequent analysis of these antibiotics is of great interest. The review discusses analytical methods for both extraction and determination of antibiotics in various food matrices focusing on the last 10 years. Extraction and clean-up methods such as deproteinization and solid-phase extraction are described, and various screening methods including TLC, EI, CE, microbiological assays, and LC combined with MS are reviewed.

Acta Chromatographica 20(4), 673-683 (2008). Presentation of a quantitative method for the analysis of lycopene in nutritional supplements consumed to reduce the risk of prostate cancer and other forms of cancer and cardiovascular disease. HPTLC on silica gel with petroleum ether – dichloromethane 9:1. Quantification by densitometry at 416 nm. Four products containing 300 µg, 3 mg, 5 mg, or 10 mg lycopene plus other ingredients were quantified using a lycopene standard: the measured amounts ranged from 77.7 to 98.1 % of the stated label values. The accuracy by spiked blank analysis was within 1.90 % of theoretical values for the 3 mg softgels and 1.10 % of theoretical values for the 10 mg softgels. The precision of replicate analyses showed a RSD of 1.44 % for the 10 mg softgels and 2.39 % RSD for the spiked blank for the 3 mg softgels. The results obtained for Lycopene standards available from two other companies showed 55.6, 57.6, and 20.0 % of the minimum amount expected from the stated label values.