J. Sep. Sci. 30, 1250-1254 (2007). HPTLC of Emblica officinalis extract on silica gel with ethyl acetate – formic acid – glacial acetic acid – water 10:1:1:2. Primary detection under UV 280 nm. Antiradical activity of individual components was estimated on intensity of disappearance of violet/purple background of plate after dipping in DPPH radical solution (0.5 mM in methanol) at room temperature for 90 s and that 30 s at 60 °C. Quantitative determination by absorbance measurement at 517 nm as negative peak. DPPH radical scavenging activity of emblicanins A and B was 7.9 and 11.2 times more active than that of ascorbic acid and 1.3 and 1.8 times more active than gallic acid, respectively.

Chromatographia 67 (3-4), 315-313 (2008). Investigation of two different chromatographic substrates and one interface for coupling surface-enhanced Raman spectroscopy (SERS) with TLC. A chromatographic thin layer, specially produced for RS measurements, and a monolithic silica thin layer were used. A typical TLC plate with a modified aluminium backplate foil on one side was used as an interface. As test analytes three biologically active diterpenes (gibberellic acid, abietic acid, and kaurenoic acid) were applied directly onto the surface, followed by the addition of silver colloid and measurements by SERS. The strongest signal (excitation at 514.5 nm) was obtained for gibberellic acid using a Raman treated thin layer where the enhancement factor value was determined to be 102. No useful SERS signals were observed when the monolithic silica layer was used. Similar SERS spectra on modified aluminium backplate were obtained for abietic acid and gibberellic acid and no SERS spectrum was obtained for kaurenoic acid.

J. Planar Chromatogr. 20, 327-330 (2007). TLC of beta-sitosterol on silica gel with toluene - ethyl acetate - glacial acetic acid 15:4:1 with chamber saturation for 30 min. Visualization by spraying with anisaldehyde reagent and heating at 90 °C for 5 min. Densitometric quantitation at 525 nm.

59th Indian Pharmaceutical Congress C-100, 248, (2007). An HPTLC method has been developed for the estimation of flavonoids tannin and saponin in Caesalpinia bonduc. The dried powdered leaves of the plant were extracted with methanol and used for evaluation. HPTLC on silica gel with ethyl acetate - formic acid - glacial acetic acid - water 20:2:2:5 for flavonoids, chloroform - glacial acetic acid - methanol - water 16:8:3:2 for saponin, and ethyl acetate - toluene - formic acid 6:6:1 for tannin. Detection by spraying with 5 % methanolic sulphuric acid for saponin, 5 % alcoholic aluminium chloride solution for flavonoids, and 5 % ferric chloride solution for tannin. Densitometric evaluation at 254 nm and 366 nm.

J. Sep. Sci. 30, 2053-2058 (2007). HPTLC of umbelliferone (1), psoralen (2), and eugenol (3) in the dried fruit pulp of Aegle marmelos and in the fruit of Trachyspermum ammi and Foeniculam vulgare on silica gel with toluene – methanol 19:1. Quantitative determination by absorbance measurement at 331 nm for (1), 304 nm for (2), and 280 nm for (3). The hRf values were 30, 58, and 70 for (1), (2), and (3), respectively. Linearity was between 1 and 5 ng/zone, 16 and 96 ng/zone, and 200 and 1000 ng/zone for (1), (2), and (3), respectively. The limits of detection and quantification were 0.8 and 1.2 ng/zone for (1), 8 and 16 ng/zone for (2), 60 and 150 ng/zone for (3), respectively. Recoveries were 98.9 %, 100.1 %, and 99.3 %, for (1), (2), and (3) respectively.

J. Planar Chromatogr. 20, 235-237 (2007). TLC of atorvastatin, cerivastatin, fluvastatin, lovastatin, and simvastatin on RP-18 in horizontal chamber with sandwich configuration with methanol - buffer eluents of different composition. The best selectivity - separation of all the compounds - was achieved with methanol - phosphate buffer pH 7.60 4:1. Detection and densitometry at 254 nm.

J. Sep. Sci. 30, 2086-2091 (2007). HPTLC of 4alpha-methyl-24beta-ethyl-5alpha-cholesta-14,25-dien-3beta-ol (1), 24beta-ethylcolesta-5,9,11,22E-trien-3beta-ol (2), and betulinic acid (3) in Clerodendrum inerme on silica gel with toluene - ethyl acetate 47:3. Quantitative determination by absorbance measurement at 620 nm. The hRf value was 48, 34 and 22 for compounds (1) , (2) and (3), respectively. Linearity was between 100 and 2500 ng/zone. The limits of detection and quantification were 5, 6, and 10 µg/mL and 14, 18, and 29 µg/mL, respectively, for (1), (2), and (3).

by TLC. Chromatographia 66 (7-8), 631-634 (2007). TLC of heraclenin and heraclenol in the roots of Heracleum candicans D.C. on silica gel with toluene - ethyl acetate 7:3. Quantitative determination by densitometry at 366 nmn. Linearity was between 4 - 10 µg/zone for heraclenin and 1 - 5 µg/zone for heraclenol.