J. Planar Chromatogr. 23, 219-224 (2010). TLC of carotenoids (lutein, beta-carotene), astaxanthin and tannin on silica gel with petroleum ether - diethyl ether - acetone 15:3:2 in a twin-trough chamber saturated for 30 min at room temperature. Quantitative determination by densitometric absorbance measurement at 450 nm. The hRf values of lutein in tea, mulberry, and cassava leaf were 19, 22, and 19 and corresponded to lutein standard. The least polar zone had an average hRf value of 98, 98, and 96 for tea, mulberry, and cassava leaf, respectively, and was identical with beta-carotene standard.

J. Planar Chromatogr. 23, 250-254 (2010). TLC of 30 food additives (aldehydes, organic acids, esters and alcohols, and various sodium salts) on titanium(IV)silicate ion-exchanger with 10 different mobile phases: e. g. methanol, heptane - diethylether 4:1, aqueous ammonia - methanol - ethyl acetate 1:3:6, methanol - aqueous ammonia 9:1, methanol - ethanol 17:3, 0.5 M ammonium sulfate solution, 0.25 M, 0.5 M and 0.1 M potassium bromide solution, and phosphate buffer pH 2.5 in a twin-trough chamber without chamber saturation. Detection by spraying with 1 % iron chloride solution, 0.5 % potassium permanganate and 3 % barium chloride solution 1:1, 1 % ninhydrin in ethanol, 2 % phosphomolybdic acid in ethanol, and 5 % potassium dichromate in concentrated sulfuric acid. The study shows that the quality of separation depends to a large extent on the mobile phase, and selectivity is achieved by varying the composition of the mobile phase.

J. Planar Chromatogr. 24, 487-490 (2011). HPTLC of vitamin D3 in fish oil after saponification and purification on silica gel with chloroform - diethyl ether 9:1 with chamber saturation for 20 min. Quantitative determination at 280 nm. Linearity was between 200 and 1000 ng/band. The LOD and LOQ were 29 and 232 ng/band, respectively. The repeatability (RSD) was 4.6 %; the %RSD for intermediate precision was 0.9; the %RSD for intra-day precision (n = 6) was between 2.9-5.9 % and the %RSD for inter-day precision (n = 6) was between 3.2-6.4 %. Recovery was 97.6 - 104.2 % with a %RSD of 3.9 - 4.8 %.

J. Planar Chromatogr. 25, 542-547 (2012). HPTLC of tartrazine in mustard on silica gel with isopropyl alcohol - ammonia 7:3. Quantitative determination by absorbance measurement at 425 nm (1) and by digital processing using a TLC scanner at an optical resolution of 300 dpi in visible mode followed by image digitalization (2). The hRf of tartrazine was 61. Linearity was in the range of 32-878 ng/zone using (1) and 92-600 ng/zone using (2). Limits of detection and quantification were 5 and 11 ng/zone using (1) and 51 and 74 ng/zone using (2). Average recovery with both methods was greater than 100 %. Lower contents of tartrazine in mustard samples were determined when TLC image processing was applied for quantification probably due to poor sensibility of calibration with this method.

Food Control. 34, 138-148 (2013). TLC was reviewed as a fast screening methodology for the determination of deoxynivalenol (DON) showing LOD in rice of 100 mg/kg. 2D-TLC on silica gel with dichloromethane - ethyl acetate - propan-2-ol 18:1:1 and toluene - ethyl acetate - formic acid 6:3:1 for the first and second runs, respectively. Detection by spraying with chromotropic acid, followed by heating at 110 °C for 5 min. Quantitative determination by absorbance measurement at 366 nm. The hRf values of DON were 13 and 20. Advantages and disadvantages of current methods as well as comparison with other techniques were also described for the effective monitoring and surveillance of DON and its derivatives.

J. Planar Chromatogr. 26, 312-315 (2013). HPTLC of L-dopa (1) and rutin (2) in a polyherbal formulation on silica gel with butan-1-ol - acetic acid - water 4:1:1 for (1) and ethyl acetate - butan-1-ol - formic acid - water 5:3:1:1 for (2). Quantification by absorbance measurement at 288 nm for (1) and 254 nm for (2). The hRf values for compounds (1) and (2) were 45 and 50, respectively. Linearity was in the range of 0.4-1.2 µg/zone for (1) and 0.4-0.9 µg/zone for (2). LOD and LOQ were 64 and 159 ng/zone for (1) and 76 and 228 ng/zone for (2), respectively. Average recoveries were 99.6 % for (1) and 100.1 % for (2). Intermediate/interday/intra-day precision was below 5 % (n=8).

J. Chromatogr. A 1381, 229-238 (2015). TLC screening and TLC-MS2 analysis of triterpenoids and phytosterols on (A) RP-18 with ethyl acetate - acetonitrile 3:2; (B) RP-18 with with acetone - acetonitrile 5:1; (C) silica gel with n-hexane - ethyl acetate 5:1. Detection of (A), (B) and (C) by dipping with a methanolic solution of anisaldehyde reagent, followed by heating at 110 °C for 30 s. Qualitative identification under white light and at UV 366 nm. The TLC-MS Interface was used for the elution of compounds from the plates into a LCQ ion trap system equiped with atmospheric pressure chemical ionization in positive mode. Acetonitrile was used as an eluent at a flow rate of 0.3 mL/min. This approach of combination TLC and MS enabled positive assignment of different triterpenoids and phytosterols.

Food Chem. 177, 354-360 (2015). HPTLC of ochratoxin A in rice bran, wheat bran and wheat flour on silica gel with n-hexane - ethyl acetate - acetic acid 36:8:3. Quantitation by absorbance measurement at UV 366 nm. Linearity was between 50 and 300 ng/zone. The LOD and LOQ for ochratoxin A was 10 and 30 ng/zone, respectively. Recovery was in the range of 86-113 %.