J. Planar Chromatogr. 17, 113-122 (2004). HPTLC of serine, threonine, phenylalanine, tryptophan, lysine, ornithine, arginine, valine, and leucine on silica gel with A) 2-propanol - ethyl acetate - 25 % ammonia - water 40:40:3:50; B) 2-propanol - acetone - water - 25 % ammonia 25:25:7:6; C) 2-propanol - 25 % ammonia 7:3; D) chloroform - 96 % ethanol - acetic acid - water (52.5-54.0):(26.0-27.5):(8.9-9.6):(3.5-4.2); E) 1-propanol - 25 % ammonia 11:9; F) 1-propanol - 25 % ammonia - water (3.3-4.1):(0.9-1.5):(7.5-9.0); G) t-amyl alcohol - 2-butanone - water 22:6:5, upper layer, in a presaturated twin-trough chamber. Detection by dipping into a ninhydrin solution. Quantitative determination by reflectance measurement at 500 nm.

Chinese J. Trad. Patent Med. (Zhongchengyao) 26 (5), 430-432 (2004). TLC of Huanwu capsules on silica gel with chloroform - methanol - water13:6:2 after being placed over night at a temperature belowe 10 ºC. Detection by spraying with 10 % H2SO4 in ethanol and heating at 105 ºC for 5 min. Identification by comparison with the standard. Quantification by densitometry at 530 nm. Validation of the method by investigation of the linear range of the calibration curve (0.98-6.86 µg/spot, R=0.998), precision (RSD=1.0 %, n=6), reproducibility (RSD=0.8 %, n=5), and standard addition recovery (98.9 %, n=6). Application of the method on real-life samples.

Chinese J. Trad. Patent Med. (Zhongchengyao) 26 (6), 452-455 (2004). TLC of Shangbiao oil extracts on silica gel with 1) n-heptane-ethyl acetate 17:3; 2) n-heptane - ethyl acetate 9:1; 3). Detection 1) by spraying with 2,4-dinitro-phenylhydrazine solution in ethanol; 2) by spraying with 5 % vanillin-H2SO4 solution and heating at 110 ºC for 5 min. Identification by fingerprint techniques. Quantification of menthol and camphor by GC.

CBS 94, 14-15 (2005). HPTLC of sucralose on amino phases with acetonitrile - water 4:1 over 70 mm. Stability of sucralose in Burfi, a milk-based confection, was determined over a defined time period. The 2 products of hydrolysis have been monitored as well. Detection by heating for 20 min at 190° C. Quantitative determination by fluorescence measurement under UV 366. Limit of quantitation in the lower ng range.

J. Planar Chromatogr. 17, 479-482 (2004) HPTLC of beta-boswellic acid (BA), acetyl-beta-BA, keto-BA, and acetyl-keto-BA and ethanolic extracts of olibanum resin on silica gel with toluene - ethyl acetate - formic acid - heptane 80:20:3:10 in a twin trough chamber without chamber saturation. Quantitative determination by reflectance measurement at 245 and 285 nm. Also two dimensional development with the same mobile phase in the second direction.

J. Planar Chromatogr. 17, 264-274 (2004). HPTLC of zidovudine (3’-azido-3’-deoxythymidine) and degradation products on silica gel with toluene - carbon tetrachloride - methanol - acetone 35:35:20:1. Quantitative determination by absorbance measurement at 270 nm. The method was validated for precision, robustness, and recovery. Limits of detection was 20 ng per spot, limit of quantitation 40 ng.

IPC 56th 2004, Abstract No. GP-3. Simultaneous HPTLC determination of valdecoxib and tizanidine in tablets on silica gel with n-butyl acetate - formic acid - chloroform 7:3:2. Quantitative determination by densitometric scanning at 283 nm. The Rf values of valdecoxib and tizanidine were 0.78 and 0.39 respectively. Linearity range was 200 - 1000 ng/spot and 60 - 300 ng/spot respectively. Mean recovery for both of the compounds was 99.57 – 101.28 %. The method was validated for accuracy, precision, linearity, LOD, and LOQ.

- Part 1. Fundamentals of systematic quantitative errors. J. Planar Chromatogr. 18, 51-56 (2005). First part of a series covering systematic errors arising in separation systems, evaluation and calibration errors, nonlinear separation and quantitation techniques, the sf4-procedure for finding total systematic errors, systematic errors caused by regulations, and conclusions and proposals for quantitative planar liquid chromatography (PLC). 1) Nonsystematic errors: 1.1 Finding systematic errors hidden in nonsystematic errors, 1.2 Are random errors unstable? 1.3 Errors caused by (false) statements. 2) The main sources of systematic errors in quantitative PLC: 2.1 Chromatography, 2.2 Physics (baseline - baseplane; practical example). 2.3 Mathematics (detectability limit of the systematic error and the standard certainty STC). 3) Sampling chromatography.