J. Planar Chromatogr. 24, 125-129 (2011). HPTLC of plant extracts and oxyresveratrol on silica gel, prewashed with methanol, with hexane - ethyl acetate - chloroform - methanol 15:10:17:8 in a twin-trough chamber lined with filter paper and saturated for 20 min. Quantitative determination by densitometry at 327 nm. LOD and LOQ were 50 and 200 ng/band, respectively. The hRf value of oxyresveratrol was 31. Intra-day and inter-day variation (%RSD) were consistently below 5.0 %. Within-day precisions for the replicate analysis (n = 3) were in the range of 1.1-4.1 %. Day-to-day replicates (n = 9) were between 2.1-2.8 %.

J. Planar Chromatogr. 24, 44-47 (2011). HPTLC of nitrazepam on silica gel with benzene - ethanol 5:1 in a horizontal chamber with saturation for 50 min. Quantitative determination by densitometry in absorbance mode at 196 nm. The hRf of nitrazepam was 68. Linearity was in the range of 0.25-10.0 µg/zone. Mean recovery was 98.8 % and 98.8 % for tablet and pure powder, respectively. Precision and accuracy (%RSD) were 1.3 % and 1.2 %, respectively. LOD and LOQ were 0.49 and 1.52 µg/mL, respectively.

Asian Journal of Chemistry 23 (5), 2046-2048 (2011). TLC of alpha- and beta-asarone in Acorus calamus on caffeine modified silica gel (with 10 % caffeine in dichloromethane and dried at 100 °C for 10 min) with toluene - ethyl acetate 93:7. The hRf value of alpha-asarone was 67 and of beta-asarone 77. Quantitative evaluation by absorbance measurement at 313 nm. The linearity was in the range of 50-1000 ng/band for beta-asarone. The alcoholic extracts of samples from different geographical regions were found to contain 0.2-0.8 % of alpha-asarone and 8.7-11.2 % of beta-asarone.

J. Planar Chromatogr. 25, 571-574 (2012). HPTLC of theanine in tea extracts on silica gel with n-butanol - acetone - acetic acid - water 7:7:2:4. Detection by dipping into a ninhydrin reagent for 3 s, followed by heating at 105 °C for 5-15 min. Quantitative determination by analysis of green channels of photographs using the CP Atlas 2.0 software. The hRf of theanine was 35. Linearity was in the range of 1.4-14 ng/zone. The intermediate/inter-day/intra-day precision was below 0.7 % (n=3). Recovery (by standard addition) was between 95.7 and 102.5 %.

J. Planar Chromatogr. 25, 48-53 (2012). HPTLC of alpha-cypermethrin in soil on silica gel with hexane - toluene 1:1. Quantitative determination by absorbance measurement at 220 nm. The hRf values for alpha-cypermethrin was 38. Linearity was in the range of 12.5-1000 ng/zone. Limits of detection and quantification were 2 and 6 ng/spot, respectively. Precision was found in the range 1.7-6.3 % (n=6). Recovery was between 90.8 and 91.2 %.

J. of China Pharm. 21 (10), 31-32 (2012). Chuanyushaoshang cream is a herbal TCM preparation for external application for protecting wounds, promoting wound healing, antibiosis, invigorating the circulation of blood, and relieving pain. For quality control, TLC of emodin, one of the key active constituents in the extracts of the preparations, on silica gel with petroleum ether (60-90 ºC) – ethyl acetate 7:3, detection at UV 366 nm.

J. Planar Chromatogr. 25, 439-444 (2012). Bivariant multiple development (BMD)-TLC of chelidonine (1), chelerithrine (2) and berberine (3) in the herb and roots of Chelidonium majus on silica gel with toluene - ethyl acetate - methanol 1:1:1 for step I, ethyl acetate - formic acid - water 7:1:1 for step II and n-propanol - formic acid - water 21:2:2 for step III. Quantitative determination by absorbance measurement at 290 nm. Linearity was in the range of 200-1500 ng/zone for (1), 200-1000 ng/zone for (2) and 250-1500 ng/zone for (3). Limits of detection and quantification were 100 and 200 ng/zone for (1), 50 and 200 ng/zone for (2) and 50 and 250 ng/zone for (3), respectively. The intermediate/inter-day/intra-day precision was below 1.6 % (n=7). Recovery for (1) to (3) was in the range of 96-105 %.

J. Planar Chromatogr. 25, 409-414 (2012). HPTLC of two anthocyanins, cyanidin-3-O-rutinoside (1) and cyanidin-3-O-glucoside (2), in the berries of Euterpe oleracea Mart. on silica gel with ethyl acetate - formic acid - acetic acid - water 100:11:11:26. Quantification by absorbance measurement at 520 nm. The hRf of compounds (1) and (2) were 29 and 37, respectively. Linearity was in the range of 100-500 ng/zone. The limit of detection was 30 ng/zone for (1) and 40 ng/zone for (2) and the limit of quantification was 100 ng/zone for both (1) and (2). The intermediate/inter-day/intra-day precision was below 2.8 % (n=3). The average recovery was between 99.8-101.8 %.