Chromatographia 65 (3-4), 245-248 (2007). TLC of dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl)phthalate (DEHP), benzyl butyl phthalate, diisodecyl phthalate, dimethyl adipate, diethyl adipate, di(2-ethylhexyl)adipate, triethyl citrate, tributyl citrate, tributyl acetyl citrate and n-butyl stearate on inorganic ion-exchanger stannic silicate with toluene - ethyl acetate 10:1 over 12 cm (25 min). Quantification of DEHP by densitometry at 280 nm. Limit of quantitation for DEHP was 0.50 µg/zone and limit of detection 0.05 µg/zone.

J. Chromatogr. A 1116 (1-2), 272-276 (2006). Application of TLC to fractionate well-characterized aquatic humic materials coupled with the novel evaluation of the trihalomethane formation potential of the fractionated materials. HPTLC on silica gel with methanol - ethyl acetate 2:1. Identification of three common fractions based on retention factor (Rf) in all substances examined.

Thieme Medical Publishers Inc., New York (2006). This book presents the theoretical and technical information needed to perform reliable and reproducible high-performance thin-layer chromatography (HPTLC) to establish the identity, purity, quality, and stability of raw materials, extracts, and finished botanical products. The text provides a complete overview of the techniques and common applications of HPTLC in herbal analysis. Chapters covered are theoretical concepts (stationary phase, mobile phase, TLC results, densitometry), practical aspects of modern TLC (sample preparation, selecting the stationary phase, sample application, chromatogram development, derivatization, documentation, reporting and record keeping, TLC software, standardization), typical applications in herbal analysis, method development, and validation of qualitative and quantitative HPTLC methods.

Food Chem. 77, 263-265 (2002). HPTLC of trehalose on silica gel, impregnated with phosphotungstic acid of pH 2.5, with n-butanol – pyridine – water 8:4:3. Detection by spraying with a solution of 6.5 mM N-(1-naphthyl)-ethylenediamine dihydrochloride in methanol, containing 3 % sulfuric acid. The hRf values of raffinose, trehalose, maltose, sucrose, glucose, and fructose were 30, 41, 46, 53, 55, and 59, respectively.

J. Sep. Sci. 30, 3311-3315 (2007). HPTLC of lawsone in the leaves of Lawsonia alba on silica gel with chloroform – methanol 17:3. Quantitative determination by absorbance measurement at 334 nm. The hRf value of lawsone was 40 and selectivity regarding matrix was given. Linearity was between 100 and 1000 ng/zone. The precision was 1.72 % and recovery (by standard addition) was 98.8 %.

CBS 97, 9-11 (2006). HPTLC of trigonelline in fenugreek (Trigonella foenum-graecum) on silica gel in a saturated twin-trough chamber with n-propanol - methanol - water 4:1:4 over 80 mm. Quantitative determination by absorbance measurement at 269 nm. The hRf value of trigonelline was 46 and selectivity regarding matrix was given. Linearity was between 100 and 1200 ng/zone. The inter- and intraday precision was below 1 %. The limit of detection and quantification was 2.3 and 7.6 ng/zone, respectively. Recovery (by standard addition) was 99 - 101 %.

J. Planar Chromatogr. 20, 457-461 (2007). HPTLC of rivastigmine ((-)-S-N-ethyl-3-[(1-dimethylamino)ethyl]-N-methylphenylcarbamate) and impurity on silica gel with chloroform - methanol 2:3 in a twin-trough chamber with chamber saturation for 30 min. Densitometric analysis was performed in absorbance mode at 210 nm. Limits of detection were 30 and 100 ng/zone, respectively.

Indian Drugs 44(8), 640 (2007). TLC, HPTLC and UV spectrophotometric methods have been developed and evaluated to compare the colour properties of saffron and Nyctanthes arbor-tristis which shows an orange red colour. HPTLC and TLC of methanolic extracts of saffron and calyx of Nyctanthes arbor-tristis on silica gel with ethyl acetate - isopropanol - water 13:5:2. Both extracts showed a major zone with hRf 23 corresponding to crocin, the major colour constituent of saffron. The presence of crocin was confirmed by UV spectra. TLC, HPTLC and UV data confirm the coloring similarity of Nyctanthes arbor-tristis.