J. Planar Chromatogr. 22, 197-200 (2009). HPTLC of whithaferin A on silica gel with toluene - ethyl acetate - formic acid 5:5:1 in a twin trough chamber saturated for 20 min at 25 +/- 2 °C and 50 +/- 5 % relative humidity. Detection under UV light and by dipping into freshly prepared p-anisaldehyde reagent, followed by heating at 110 °C for 10 min. Quantitative determination by absorbance measurement at 200 nm. The limit of detection and quantification was 100 and 800 ng/zone, respectively. The high sample throughput is useful for routine analysis of the preparation in industrial quality control and regulatory laboratories.

J. Chromatogr. A 1216 (11), 2150-2155 (2009). Chaihu roots (Bupleuri radix), roots of Bupleurum chinense and Bupleurum scorzonerifolium are monographed in the Chinese Pharmacopoeia. Evaluation of the quality of 33 lots of authenticated Chaihu samples versus 31 lots of commercial samples by HPLC-ELSD and HPTLC analysis of the principal bioactive components (saikosaponins). Data acquired from HPLC fingerprints and HPTLC fluorescent images was analyzed by chemometrics for similarity and pattern recognition, including artificial neural networks, k-nearest neighbor (k-NN) and an expert’s panel. The k-NN classifier showed good performance with sufficient flexibility for processing HPTLC fingerprint images. These images were otherwise not easily dealt with by other algorithms due to the shift of hRf values and varying hue/saturation of the band colors between different TLC plates. The two chromatographic fingerprint methods are complementary measures for quality control. Chaihu roots from different species of the genus Bupleurum could readily be distinguished from each other. Commercial samples of Chaihu can easily be classified by investigating the content of major saikosaponins.

J. AOAC Int. 92, 779-784 (2009). HPTLC of psoralen and plumbagin and extracts of ayurvedic polyherbal oil formulations on silica gel at 22 °C and 55 % humidity with toluene - ethyl acetate 3:1 in a twin trough chamber with chamber saturation. UV spectra were recorded from 200 to 600 nm; densitometric measurements were performed at 302 nm (for psoralen) and 275 nm (for plumbagin).

J. Chinese Trad. & Herb. Drugs 40 (8), 245-247 (2009). TLC of the TCM drug extracts on silica gel with 1) petroleum ether (90-120 °C) – toluene – formic acid 20:40:1; 2) chloroform – ethyl acetate – methanol – water – formic acid 3:10:2:2:2; 3) ethyl acetate – formic acid – water 12:2:3. Detection 1) by spraying with 10 % sulfuric acid in ethanol followed by heating at 105 °C; 2) by exposure to iodine vapor; 3) under UV 254 nm.

pruriens. Abstract No. 9425, IHCB (2009). HPTLC of L-dopa in Mucuna pruriens seed extract and formulations on silica gel with n-butanol - acetic acid - water 4:1:1. Quantitative determination by absorbance measurement at 280 nm. The method was linear in the range of 100-1200 ng/spot with an average recovery of 100.3 %.

Indian Drugs 46(6), 493-496 (2009). HPTLC of chloroform extracts of the bark of Ficus racemosa, F. bengalensis, and F. religiosa on silica gel with toluene - ethyl acetate - formic acid 90:10:1. Detection under UV 254 nm and visible light after treatment with vanillin sulfuric acid reagent, followed by heating at 105 °C until coloration.

60th Indian Pharmaceutical Congress PG-349 (2008). HPTLC of 3H-4M-benzaldehyde (in crude plant material, extracts and dosage form of Hemidesmus indicus) on silica gel with toluene - ethyl acetate - methanol - acetic acid 15:3:1:1. Quantitative determination by absorbance measurement at 230 nm.

J. AOAC Int. 93, 492-495 (2010). HPTLC of glycyrrhizin on silica gel with chloroform - methanol - water 130:72:15 in a twin-trough chamber saturated for 30 min. Detection under UV 254 nm and after spraying with anisaldehyde-sulfuric acid reagent. The hRf value of glycyrrhizin was 22. Quantitative determination by densitometry at 254 nm. The linearity was between 0.96-4.80 µg/spot, the correlation coefficient was r = 0.99904 and the standard deviation was 2.52 %. Average recovery was 99.6 %. LOQ and LOD was 246 and 81 ng/spot.