J. Planar Chromatogr. 24, 77-81 (2011). HPTLC of belleric acid on silica gel, prewashed with methanol, with toluene - ethyl acetate - methanol - formic acid 15:15:7:1 in a saturated chamber at 22 °C and 65 % relative humidity. Quantitative determination by absorbance measurement at 205 nm. Average recovery was 98.7-100.9 %. Linearity was between 250 and 1250 ng/zone. Repeatability and intermediate precision (%RSD) were 1.2 and 1.5 %, respectively. LOD and LOQ were 49 and 148 ng/zone, respectively. The hRf value of belleric acid was 35.

J. Planar Chromatogr. 24, 337-343 (2011). TLC of tenoxicam and pyridine-2-amine on silica gel with ethyl acetate - toluene - butylamine 2:2:1 with chamber saturation for 15 min at room temperature. Quantitative determination by absorbance measurement at 288 nm. The hRf value was 52 and 64 for tenoxicam and pyridine-2-amine, respectively. Linearity was between 35-1820 mg/mL for tenoxicam and 10-500 mg/mL for pyridine-2-amine. LOD and LOQ were 0.9 and 2.6 mg/band for tenoxicam and 0.1 and 0.3 mg/band for pyridine-2-amine. The recovery was 99.0-99.9 % for tenoxicam and pyridine-2-amine. The %RSD did not exceed 1 % at any level.

J. Planar Chromatogr. 25, 344-348 (2012). HPTLC of two oil-soluble sunscreens, namely avobenzone (1) and octyl salicylate (2) and a water-soluble sunscreen, namely phenylbenzimidazol sulfonic acid (3) on silica gel with cyclohexane - diethyl ether 5:1 for (1) and (2) and ethyl acetate - ethanol - water 14:7:6 for (3). Quantitative determination by absorbance measurement at 300 nm for (2) and (3), and 360 nm for (1). Limits of detection and quantification were found to be 30 and 80 ng/zone for (1), and 20 and 60 ng/zone for both (2) and (3).

J. Planar Chromatogr. 25, 262-268 (2012). HPTLC of paraquat (1), diquat (2), difenzoquat (3), mepiquat (4), and chloromequat (5) in water on silica gel with 1-propanol - methanol - 2.5 N NaCl 1:1:3. Quantitative determination by absorbance measurement between 500 and 535 nm. The hRf values of compounds (1) to (5) were 21, 30 36, 52 and 56, respectively. Limits of quantification were 5 ng/zone for (1), 2 ng/zone for (2), 25 ng/zone for (3), 15 ng/zone for (4) and 9 ng/zone for (5). Recovery rates for compounds (1) to (5) were 50.7, 65.2, 59.6, 45.1 and 33.7 %, respectively.

J. Planar Chromatogr. 25, 575-580 (2012). HPTLC of echioidinin-5-O-beta-D-glucopyranoside in Andrographis echioides on silica gel with chloroform - methanol 31:9. Quantitative determination by absorbance measurement at 254 nm. Linearity was in the range of 200-1400 ng/zone. Limits of detection and quantification were found to be 54 and 68 ng/zone, respectively. Recovery (by standard addition) was 96.7 %.

J. Ethnopharmacol. 138, 755-771 (2012). HPTLC studies of Harpagophytum procumbens such as the quantification of harpagoside were reviewed. HPTLC of harpagoside in the roots of Harpagophytum procumbens on silica gel with dichloromethane – methanol – acetic acid 79:20:1. Detection by dipping into anisaldehyde – methanol – acetic acid – sulphuric acid 1:170:20:10, followed by heating at 120 °C for 5 min. Quantitative determination by absorbance measurement at 285 nm. HPTLC provides comparable results with HPLC but is less time consuming.

J. Liq. Chromatogr. Relat. Technol. 35, 2396-2407 (2012). HPTLC of vanillin in the roots of Decalepis hamiltonii Wight and Arn on silica gel with toluene - ethyl acetate 9:1. Quantitative determination by absorbance measurement at 254 nm. The hRf value of vanillin was 42. Linearity was in the range of 2-12 µg/zone. Limits of detection and quantification were 1.3 and 3.9 µg/zone. The intermediate/inter-day/intra-day precision was 1.3 % (n=3), respectively. Recovery was between 99.4 and 100.3 %.

CBS 108, 12-15 (2012). HPTLC of anthracene (ANT), benzo[b]fluoranthene (BBF), benzo[k]fluoranthene (BKF), pyrene (PYR), acenaphthene (ACE), benzo[a]anthracene (BAA), benzo[a]pyrene (BAP), benzo[ghi]perylene (BPE), chrysene (CHR), dibenzo[a,h]anthracene (DBA), indeno[1,2,3-c,d]pyrene (IND), fuorene(FLU), fuoranthene (FLA), and phenanthrene (PHE) in toys on RP-18 phase with acetonitrile - water 9:1 by three-fold development over 45, 55 and 65 mm using automated multiple development (AMD) under nitrogen. Detection at 254 and 366 nm. Quantitative fluorescence measurement at different excitation wavelengths with cut-off filters: 220 nm/>320 nm for ACE, 250/>320 for ANT, 366/>400 for BAA and BAP, 270/>400 for BBF, BPE, BKF, CHR, DBA, FLA, IDN (after dipping in nitromethane), 250/>320 for FLU and PHE and at 270/>320 for PYR. Polynomial regression with high coefficients of correlation and low standard deviations. Coeffivients of variation for repeatability and reproducibility were below 10 %. This method allows the determination of 14 of the 16 PAHs. With LODs of 0.1-0.2 mg/kg the demands for the German GS mark (label for checked safety) are fulfilled. The results by HPTLC were comparable to results obtained by GC-MS.