59th Indian Pharmaceutical congress F-225, 443, (2007). HPTLC cinnamaldehyde in the bark powder of Cinnamomum zeylenicum on silica gel with toluene - ethyl acetate - formic acid 190:10:1. Densitometric evaluation at 295 nm for quantification. The method was linear within the range of 31 and 157 ng/zone. The identity of the compound was confirmed by over overlaying the UV spectra of sample and standard. Cinnamomum bark was found to contain 0.25 % of cinnamaldehyde. Limit of detection and quantification was 3000 and 9900 ng/mL, respectively.

J. Chromatogr. A 1183 (1-2), 179-185 (2008). Ultrathin layer chromatography (UTLC) with a 10 µm thick monolithic silica sorbent layer provides fast separations with low limits of detection and reduced analyte and solvent volumes. Production of UTLC plates with controllable nanostructure and thickness. The separation characteristics of the layer depend on the nanostructure of the film. Layers made with in-plane anisotropic nanostructures exhibit a decoupling effect, where the analyte spots do not develop in the same direction as the solvent front moves. Discussion of the possibility of application in multi-dimensional TLC by added layer morphology and material selection.

Biochem. Biophys. Res. Commun. 365, 118-123 (2008). TLC of prenyl alcohols (farnesol and geranylgeraniol) after enzymatic hydrolysis of trans-isoprenyl diphosphates on RP-18 with acetone - water 9:1. Detection with iodine vapour. Quantitative determination by measuring the absolute radioactivity of the spots.

CBS 100, 2-5 (2008). HPTLC of photodegraded UV filters and sunscreen on silica gel LiChrospher prewashed with methanol. AMD 2 development of UV filter standards photodegradation products with diisopropylether - n-hexane in 6 steps over 50 mm without preconditioning, and of sunscreen samples photodegradation products with t-butylmethylether - n-hexane in 7 steps over 50 mm with preconditioning, followed by drying at 120 °C for 30 min. Detection at 254 and 366 nm, followed by biodetection via dipping the plate in a Vibrio fischeri solution for 1 s and evaluation with the Bioluminizer (exposure time 55 s). Densitometric evaluation by multi-wavelength scan at 200-400 nm.

J. Sep. Sci. 31, 47-55 (2008). HPTLC of phyllanthin (1), hypophyllanthin (2), niranthin (3), and nirtetralin (4) in the leaves of four Phyllanthus species, P. amarus, P. maderaspatensis, P. urinaria, and P. virgatus, on a chiral TLC plate with n-hexane - acetone - 1,4-dioxane 18:2:1. Detection by dipping in vanillin reagent (1 g vanillin, 5 mL sulphuric acid, 95 mL ethanol) followed by heating at 110 °C for 15 min. Quantitative determination by absorbance measurement at 620 nm. The hRf values were 30, 36, 41, and 48 for (1) to (4), respectively. Linearity was between 100 and 500 ng/band and the recoveries for (1) to (4) were 99.9, 100.5, 99.2, 98.7 %, respectively. The limit of detection and quantification was 26 and 88, 45 and 136, 53 and 176, and 57 and 187 ng/band for (1) to (4), respectively. No significant intra- and interday variation was observed.

J. Liq. Chromatogr. Relat. Technol. 31, 1969-1976 (2008). TLC of urethane on spherical silica gel with methyl-t-butyl ether - methanol 7:3. Detection by immersion in a solution of 80 µL cinnamaldehyde in 40 mL acetone with 2.4 mL phosphoric acid followed by heating in an oven at 130 °C for 10 min. The fluorescence can be enhanced by the factor of 2 if the plate is dipped for 4 s into a solution of 10 % polyethylene glycol 600 in methanol. Quantitative determination by absorbance measurement in the range of 445 to 460 nm.

J. Chromatogr. A 1207 (1-2), 155-159 (2008). HPTLC of secoisolariciresinol diglucoside in flaxseed on RP18W with methanol - 0.1 % formic acid 2:3, using the alkaline hydrolysis in aqueous medium of undefatted samples. Quantitative determination by absorbance measurement at 282 nm. Validation of the method following the protocol proposed by the Société Francaise des Sciences et Techniques Pharmaceutiques lead to a dependable and high throughput procedure well suited for routine application. Linearity was between 321–1071 ng/zone and the RSD of repeatability and intermediate precision did not exceed 3.6 %.

CBS 101, 2-4 (2008). HPTLC of amino acids (from hydrolysis of peptides) on silica gel, Diol phase, and cellulose with either 2-butanol - acetic acid - pyridine - water 15:3:10:12 or 2-butanol - 25 % ammonia - pyridine - water 39:10:34:26 in a twin-trough chamber or horizontal chamber. Detection by dipping in ninhydrin solution (0.5 % in 2-propanol) followed by heating at 110 °C for 5 min. Better results are achieved by adding ninhydrin directly to the mobile phase at a 0.5 %-level. Quantitative determination by absorbance measurement at 440 nm. Selectivity was better on the cellulose and silica gel plate. Selection of the chromatographic system depended on which amino acids had to be separated and no general recommendation could be given. HPTLC analysis of a hydrolyzed peptide sample (containing Phe, Trp, D-Bal, Apc and Inp) on cellulose with the acidic mobile phase. All five amino acids were quantified between 70 and 130 % of the theoretical value for non-stable amino acids (degradation 5 to 30 %).