Acta Chrom. 11, 108-117 (2001). TLC of polyaromatic carbonyl compounds most commonly found in environmental samples (acridone, 1,2-naphthoquinone, 9,10-phenanthrenequinone, acenaphthenequinone, xanthone, 1-aminoanthraquinone, anthrone, 1,4-chrysenequinone, anthraquinone and 9-fluorenone) on silica gel and RP-18. Different combinations of solvents were evaluated as mobile phases. The best separation was obtained by use of pure dichloromethane on silica gel and methanol – water – acetonitrile 3:2:1 on RP-18 in a horizontal chamber. Evaluation under UV 254 nm and 366 nm. Quantitative determination of acridone by fluorescence measurement at 390/>400 nm, and by absorbance measurement at 250 nm for the other compounds.

CBS 98, 9-11 (2007). Quantitative HPTLC of polycyclic aromatic hydrocarbons (PAH) from water samples, on caffeine-impregnated silica gel, with isopropyl acetate in a precooled (-20 °C, 30 min) twin-trough chamber without chamber saturation over 70 mm at -20°C. After application the dry plate was first equilibrated in the solvent-free trough for 10 min at -20 °C. Qualitative HPTLC at room temperature in the horizontal developing chamber with isopropyl acetate - n-hexane 3:1 over 50 mm. Detection by dipping in paraffin - toluene 1:1 (for fluorescence enhancement). Quantitative determination by fluorescence measurement at UV 366/>400 nm. Qualitative evaluation under UV 366 nm. The method is based on the German standard DIN 38407-7 for quantitative determination of 6 PAH but uses isopropyl acetate as a chlorine-free solvent instead of dichloromethane.

J. Planar Chromatogr. 22, 59-63 (2009). HPTLC of paraquat, diquat, difenzoquat, mepiquat, and chloromequat on LiChrospher silica gel with 1-propanol - methanol - 2.5 M aqueous sodium chloride 1:1:3. Detection by immersion for 2 s in a solution of 50 mg sodium tetraphenyl borate in 50 mL of water containing 50 µL concentrated hydrochloric acid. The wet plate was illuminated for 5 min with UV light at 254 nm which resulted in the formation of fluorescing spots corresponding to mepiquat, chloromequat, and difenzoquat. Immediately after illuminating at 254 nm all spots were illuminated for 10 min with UV light at 365 nm, which converted all compounds into fluorescent derivatives. Then the dry plate was dipped into ethylene glycol - methanol 1:1 for 2 s, which enhanced the fluorescence by a factor of two. Detection by fluorescence measurement and averaged densitograms were obtained in the emission wavelength range from 440 to 480 nm.

J. of Chromatogr. A 1218 (37), 6540-6547 (2011). New approach and application of highly automated planar chromatographic tools for powerful clean-up, called high-throughput planar solid phase extraction (HTpSPE), which is indispensable for preventing matrix effects in multi-residue analysis of pesticides in food by liquid and gas chromatography coupled to mass spectrometry, employing TLC to completely separate pesticides from matrix compounds and to focus them into a sharp zone, followed by extraction of the target zone by the TLC-MS interface, thus resulting in extracts nearly free of interference and free of matrix effects, as shown for seven chemically representative pesticides in four different matrices (apples, cucumbers, red grapes, tomatoes), and completion of clean-up of one sample in a manner of minutes. Regarding the clean-up step, quantification by LC–MS with mean recovery (against solvent standards) of 90–104% and relative standard deviations of 0.3–4.1% (n = 5) for two spiking levels of 0.1 and 0.5 mg/kg.

CBS 109, 13-15 (2012). HPTLC-AMD of tolyltriazoles and by-products after ozone treatment of water samples, on LiChrospher silica gel (pre-washed with 2-propanol and dried at 120 °C for 30 min) by automated multiple development (AMD) using a 22-step gradient from methanol - formic acid 200:1 over dichloromethane to n-hexane. Detection under UV 254 nm and by spraying with 2,4-dinitrophenylhydrazine reagent, evaluation under white light. Densitometric measurement at 190, 200, 220, 240, 260, 280, and 300 nm before derivatization and at 380, 400, and 420 nm after derivatization. Coupling of HPTLC with HPLC-QTOF/MS using the TLC-MS Interface offline with water - acetonitrile 1:1 with 5 mmol ammonium acetate as extraction solvent and a flow rate of 0.2 mL/min.

Microwave assisted synthesis of berberrubine and its assessment as fluorescent chemosensor for alkanes. Tetrahedron. 71, 6148-6154 (2015). HPTLC of berberrubine and mixtures with known proportions of alkanes with different number of C atoms on silica gel with n-heptane over 30 mm migration distance, followed by heating at 65 °C for 30 min. Quantitation of non-absorbing alkanes by fluorescence determination at UV 365/>400 nm.

Food Res. Int. 89, 565-573 (2016). HPTLC of galacturonic acid (1), galactose (2), glucose (3), mannose (4), arabinose (5), xylose (6) and rhamnose (7) in neutral hydrolysates from 5 plant secondary raw materials (sugar beet pulp, walnut shell, cocoa bean husk, onion peel and pea pods) on silica gel, impregnated by immersion in 0.5 M solution of monosodium phosphate, three times with acetonitrile – water – ethyl acetate – 1-propanol 17:3:4:4. Detection by dipping into diphenylamine-aniline-phosphoric acid reagent (2 % solution of diphenylamine and aniline, each in phosphoric acid – methanol 1:4), followed by heating at 150 ºC for 3 min. Qualitative identification using white light illumination. The hRF values for (1) to (7) were 1, 15, 22, 28, 37, 54 and 83, respectively.

Chem. (Bunseki Kagaku) 33, 519-523 (1984). (Japanese). (Colorimetric determination of dispersed oils from river water by thin-layer chromatography.) TLC of various mineral oils, glycerides and fatty acids on silica with water - saturated chloroform. Determination by first treating the spots with a mixture of H2SO4, K2Cr2O7 and Ag2SO4 and then measuring the absorption of Cr(III).