Dünnschicht-Chromatographie InCom Sonderband 1996, 157-165. HPTLC of benzo[g,h,i]perylene, indeno[1,2,3]pyrene, benzo[a]pyrene, benzo[b]fluoroanthene, benzo[k]fluoroanthene and fluoroanthene on caffeine-impregnated silica prewashed with dichloromethane, precooled for 30 min at -20 °C, with dichloromethane at -20 °C. After removal of the eluent the plates are dipped for 2 s into a solution of paraffin (low viscosity)/n-hexane 1:2 and dried again (for stabilization and intensification of the inherent fluorescence of the PAH). Quantification by densitometry.

J. Planar Chromatogr. 11, 38-42 (1998). HPTLC of linamarin on silica gel (prewashed with methanol) with ethyl acetate - acetone - water 4:5:1 for 30 mm; then ethyl acetate - formic acid - water 6:1:1 to a distance of 85 mm. Developments were performed in an unsaturated chamber. Visualization by dipping into a solution of aniline (2%), diphenylamine (2%), and phosphoric acid 15% in acetone, followed by heating at 105°C for 60 min. Quantitation by densitometry at 525 nm. Simple, quick and accurate quantitative HPTLC procedure.

TrAC 21, 468-486 (2002). The article describes the valuable lessons learned from EU while funding a method-validation project (1996-2000) to meet European mycotoxin control in foodstuffs. It shows the performance characteristics of validated and official methods for aflatoxins, the selection and development of methods for validation, and the preparation of naturally contaminated mycotoxin test materials for validation studies. The authors put special emphasis on validation of TLC methods for mycotoxins for developing countries, as the main exporters to Europe of food and food products.

Food Chem. 79, 337-342 (2002). HPTLC of polyphenol compounds (caffeic acid derivatives, quercetin and kaempferol glycosides) in the leaves of Lactuca sativa on RP-18 with water – methanol – acetic acid 25:25:3. Detection by dipping into a solution of 1 % ethanolamine diphenylborate in methanol for 24 h. Quantitative determination by absorbance measurement at 365 and 440 nm. The total flavonoid amount is expressed as isoquercitrin using a three point regression curve in the range of 1 and 5000 ng/zone.

J. AOAC Int. 92, 725-729 (2009). HPTLC of acrylamide extracted from coffee samples on silica gel with ethyl acetate - tert. butyl methyl ether 4:1 in a twin trough chamber or automatic developing chamber. Pre-chromatographic in situ derivatization of the extracts (applied as area) by overspraying with dansulfinic acid produced the fluorescent dansylpropanamide band. Quantitative determination by fluorescence measurement at 254/>400 nm. The limit of quantification was 48 µg/kg. The linearity over the whole procedure showed determination coefficients between 0.9995 and 0.9825 (n = 6). The within-run precision (%RSD, n = 6) of the chromatographic method was 3%. Commercial coffee samples analyzed showed acrylamide contents between 52 and 191 µg/kg, which was in correlation with amounts reported in publications.

Microbiol. Res. 166, 255-267 (2011). TLC of lipopeptides (produced by Pseudomonas species in cultures of Pleurotus ostreatus; Pseudomonas reactans was used as a reference) on silica gel with chloroform – methanol – ammonia 80:25:4. Detection by spraying with 0.1 % bromothymol blue in ethanol, followed by heating.

J. AOAC Int. 95, 1371-1377 (2012). HPTLC of organophosphate and carbamate pesticides such as chlorpyrifos (1), paraoxon (2), parathion (3) and pirimicarb (4) in fresh fruits and vegetables on silica gel in an automatic development chamber with methanol – dichloromethane 1:9 and n-hexane – ethyl acetate - dichlormethane 13:4:3. Matrix interferences were visualized at 366 nm after dipping in primuline reagent (0.5 g/L in acetone – water 4:1). Detection by immersion in a solution of rabbit liver esterase or cutinase, followed by horizontal incubation for 30 min at 37 °C. The enzymatic reaction was stopped by heating the plate at 50 °C for 5-7 min. Staining was performed with a mixture of 60 mL Fast Blue Salt B (2.5 g/L in water) and 30 mL alpha-naphythyl acetate (2.5 g/L in ethanol). Recoveries were in the ranges of 86-109, 95-129, 96-114 and 90-111 % for pesticides (1) to (4), respectively. Mean %RSD was 8.5 for all samples.

CBS 111, 7-9 (2013). HPTLC of benzophenone-3 (BP-3), butyl methoxydibenzoyl-_x000D_methane (BM-DBM), 3-benzylidene camphor (3‑BC), 4‑methylbenzylidene camphor (4‑MBC), octocrylene (OCR), ethylhexyl methoxycinnamate (EHMC), ethyl-hexyl salicylate (EHS), diethylhexyl butamido triazone (DEBT), octyldimethyl p-aminobenzoic acid (OD-PABA), 2-hydroxy-4-methoxy-benzophenone-5-sulfonic acid (HMBS), ethylhexyl triazone (EHT) on amino phase with petroleum ether - t-butyl-methyl ether - methanol 7:2:1 and 1 % triethylamine (HMBS with methanol – acetic acid 9:1), migration distance max. 48 mm from lower edge. For reaction with the UV filters the plate was stored up to 2 h in a dark at room temperature, then heated to 33 °C, and irradiated under natural sunlight or with a Suntest CPS+ at 350 W/m2. Quantitative absorbance measurement at UV 254 nm. The UV filters known as common triggers for photoallergic reactions showed the greatest tendency to bond to the amino phase. Thus, the developed screening method is well suited to estimate the potential of_x000D_ different UV filters to form protein adducts and to identify possible skin sensitizers.