Acta Chromatographica 14, 60-69 (2004). TLC on silica gel with 1-butanol - glacial acetic acid - water 3:1:1 with chamber saturation. Detection by spraying with ninhydrin reagent (0.3 g ninhydrin in 100 mL 1-butanol plus 2 mL glacial acetic acid), followed by heating at 110 ºC for several min. Quantification by densitometry at 495 nm. Validation of the accuracy by analysis of spiked blank and standard addition samples and precision by performing replicate analysis on a single day and on different days. Recoveries and RSD for spiked blank and standard addition samples were 98.8 % and 98.5 %, 1.92 % and 0.67 %, respectively. Discussion of use of the method for the routine quality control of nutritional supplements.

J. Chinese Trad. Patent Med. (Zhongchengyao) 26 (1), 73-74 (2004). TLC on silica gel with petroleum ether - ethyl acetate 19:1. Detection under UV 365 nm. Identification by standard comparison. Quantification of ligustilide by densitometry at 290 nm. Validation of the method by investigation of its precision (RSD 2.4 % n=5 within plate and 3.0 % n=5 plate-to-plate), reproducibility (2.5 % n=6 within three hours), and recovery (96.7 %, RSD 2.2 % n=5).

CBS 86, 7 (2001). HPTLC on silica gel in horizontal development chamber with acetone - water 9:1 with chamber saturation for 15 min. Detection by dipping 1 s in 0.02 % 4-nitrosodimethylaniline in ethanol with 0.01 N HCl (adjusted at pH 2) followed by heating at 150 °C. Quantitative determination by absorbance measurement at 495 nm.

J. AOAC Int. 86, 909-915 (2003). In quality control and stability testing of herbal medicinal products, fingerprint chomatograms are used as powerful tools to evaluate and compare the composition of compounds in such products. To fulfill the ICH- and GMP-based regulatory requirements in pharmaceutical QC, chromatographic fingerprint analysis needs to be validated. By considering the stationary phase, sample application, developing solvents, chromatogram development, plate labeling, derivatization, documentation, and chromatographic equipment the paper provides a comprehensive concept for evaluating validation parameters for planar chromatographic fingerprinting based on a standardized methodology. Validation parameters addressed include stability of the analyte, selectivity, robustness testing, and method reproducibility.

J. Planar Chromatogr. 17, 36-39 (2004). TLC of saussurine on RP-18 after preconditioning for 15 min with e. g. methanol - water 2:1, tetrahydrofuran - chloroform 4:1, and methanol - water - glacial acetic acid 80:4:1; the last was found to enable the optimum separation. Detection by treatment with Dragendorff’s reagent. Quantitative determination at 540 nm. Limit of detection 3 µg.

Chinese J. Trad. Patent Med. (Zhongchengyao) 26 (4), 343-345 (2004). TLC of ephedrine chloride on silica gel with chloroform - methanol - ammonia 200:35:6. Detection by spraying with 0.5 % ninhydrin in ethanol followed by heating at 105 ºC for a few minutes. Quantitative determination at 510 nm. Validation of the method by investigation of linear range of the calibration curve (0.42 - 2.10 µg/spot, R = 0.999), precision (RSD = 2.1 %, n=6 within plate and 2.7 %, n = 5 plate-to-plate), reproducibility (RSD = 2.3 %, n = 5), and recovery (98.1 %, n = 6). The results obtained by using the method are given towards some real-life samples.

Chinese J. Trad. Patent Med. (Zhongchengyao) 26 (1), 16-19 (2004). TLC of neutral sugars, rhamnose, xylose, and glucose, extracted from Ulva pertusa alga, on silica gel with n-butanol - ethyl acetate - isopropanol - acetic acid - water - pyridine 7:20:12:7:6:6. Detection by spraying with a solution of aniline hydrogen phthalate (0.93 g) – phthalic acid (1.66 g) – water saturated n-butanol (100 mL), followed by heating at 110 ºC for 10 min. Identification and quantification by comparison with the standards. Application of an orthogonal test to investigate the effects of four factors (volume of water, temperature, extraction time, and pH) on the yield of the compounds, and determination of the optimum extraction conditions.

J. Planar Chromatogr. 17, 181-185 (2004). HPTLC of an inclusion complex of coenzyme Q10 with beta-cyclodextrin on silica gel by one-dimensional, two-dimensional, and multi-dimensional separation with 1) dioxane - water 1:1 and 2) chloroform - methanol 11:9. Detection by spraying with 5 % phosphomolybdic acid in ethanol and drying at 110 °C, followed by spraying with 50 % sulfuric acid and heating at 120 °C for 5 min.