J. Planar Chromatogr. 24, 367-372 (2011). TLC of piroxicam, meloxicam, tenoxicam, and isoxicam on silica gel with ethyl acetate - ethanol - toluene 6:3:1 + 2 drops of 25 % ammonia. Quantitative determination by densitometry in absorbance mode at 360 nm. Linearity was between 50-500 ng/zone. The hRf value was 53 for piroxicam, 78 for meloxicam, 61 for tenoxicam, and 82 for isoxicam. LOD were 10, 30, 10, and 20 ng/zone and LOQ were 20, 80, 40, and 40 ng/zone for piroxicam, meloxicam, tenoxicam, and isoxicam, respectively. The recovery was in the range of 93.2-102.9 % with %RSD of less than 1 %. The inter- and intra-day precision (%RSD) was between 0.3-0.8 %.

J. Planar Chromatogr. 25, 394-402 (2012). 2D-HPTLC of kaempferol, quercetin, rutin, hyperoside, ferulic acid, gallic acid, caffeic acid, chlorogenic acid, chinic acid, p-coumaric acid, catechin, epicatechin, and resveratrol in the flowers of Eupatorium cannabinum on cyano phase with propan-2-ol mixed with n-heptane, and ethyl acetate mixed with n-heptane as non-aqueous mobile phases in the first direction and after turning the plate 90 ° with methanol mixed with water in the second direction of development. Detection by spraying with diphenylborinic acid 2-aminoethylester and PEG 4000 or DPPH radical reagent. Evaluation under UV 254 nm and 366 nm. The 2D-HPTLC system allowed the separation of the phenolic fractions.

of Chromatogr. A 1231, 59-65 (2012) Reversed-phase HPTLC of lutein, lycopene and beta-carotene standards on RP-18 (pre-washed by development with dichloromethane – methanol 1:1) with methanol – acetone 1:1 with 0.1 % of 2-tert-butylhydroquinone. The hRf value was 4 of lutein esters, 24 of beta-carotene, 32 of lycopene, and 68 of lutein. Quantitative determination of lutein by densitometry at 450 nm. The repeatabilities were %RSD = 3.4, 1.3 and 1.6 at levels of 5 ng, 15 ng and 25 ng, respectively (n = 6). The calibration curve was best fit with a polynomial function in the range of 5-30 ng. The LOD was 1.5 ng, the LOQ 5 ng. With these chromatographic conditions also dietary carotenoids lutein esters, lycopene, free lutein and ß-carotene from food supplements were identified. It was shown that the standards remain stable on the plate for 1 h after chromatogram development.

J. Planar Chromatogr. 25, 534-541 (2012). TLC of anthocyanins and anthocyanidins in berry fruits on cellulose layers with hydrochloric acid - glacial acetic acid - water 10:1:3. Quantitative determination by absorbance measurement at 520 nm. The hRf values obtained for pelargonidin and cyanidin were 78 and 58, respectively. The TLC method was complementary to an HPLC method and allowed for identification of the major anthocyanidins characteristic for each berry fruit.

J. Planar Chromatogr. 25, 415-419 (2012). HPTLC of apigenin (1), quercetin (2), hyperoside (3), vitexin (4) and vitexin-2”-O-rhamnoside (5) on silica gel with acetonitrile - methanol - water 1:1:2 + 1 drop formic acid. Quantitative determination by absorbance measurement at 254 nm. The hRf of (1) to (5) were 12, 20, 48, 53 and 59, respectively. Linearity was in the range of 400-1250 ng/zone for (1) and (2) and 800-2500 ng/zone for (3) to (5). Limits of detection and quantification were 100 and 310 ng/zone for (1), 200 and 630 ng/zone for (2) and (3) and 300 and 960 ng/zone for (4) and (5), respectively, The intermediate/inter-day/intra-day precision was below 2.2 % (n=3). Recovery for all (1) to (5) was between 97.1 and 100.2 %.

J. Liq. Chromatogr. Relat. Technol. 35, 524-532 (2012). HPTLC of atorvastatin calcium (1), ezetimibe (2), and fenofibrate (3) in tablet on silica gel with toluene – chloroform – methanol 23:15:7 + 1 drop glacial acetic acid. Quantitative determination by absorbance measurement at 253 nm. The hRf values of active agents (1) - (3) were 20, 33 and 80, respectively. Linearity was 200-800 ng/zone for (1) and (2) and 4-16 µg/zone for (3). The intermediate/inter-day/intra-day precision was below 1.1 % for (1), 1.3 % for (2) and 1.5 % for (3) (n=6). The limits of detection and quantification were 19 and 59 ng/zone for (1), 23 and 68 ng/zone for (2), and 1449 and 4390 ng/zone for (3), respectively. Recovery (by standard addition) was between 99.1 and 99.8 % for compounds (1) to (3).

J. Chil. Chem. Soc. 57, 1033-1035 (2012). HPTLC of propanolol hydrochloride (1) and flunarizine dihydrochloride (2) in combined dosage form on silica gel with methanol - toluene - ammonia 14:6:1. Quantitative determination by absorbance measurement at 267 nm. The hRf of compounds (1) and (2) were 63 and 48, respectively. Linearity was in the range of 800-4800 ng/zone for (1) and 200-1200 ng/zone for (2). Limits of detection and quantification were 25 and 75 ng/zone for (1) and 16 and 48 ng/zone for (2), respectively. Intermediate/intra-day/inter-day precision was below 2.0 % (n=6). Recovery for both (1) and (2) was between 99.3 and 100.9 %.

J. Planar Chromatogr. 25, 368-373 (2012). HPTLC of rebamipide on silica gel with toluene - methanol - triethylamine 16:9:1. Quantitative determination by absorbance measurement at 230 nm. The hRf of rebamipide was 59. Linearity was in the range of 100-600 ng/band. Limits of detection and quantification were 6 and 18 ng/band, respectively. Intermediate intra-day/inter-day precision was below 1.7 % (n=3). Recovery (by standard addition) was between 100.1 and 100.9 %. The proposed HPTLC method is equivalent to a reported HPLC method.