V. Separation and determination of chromium (VI). Acta Chrom. 12, 170-176 (2002). Rapid and selective method for the separation and determination of Cr (VI) from Al (III), Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II), Se (IV), Sr (II), Zr (IV), Cd (II), La (III), Ce(III), Hg(II), and U (VI). TLC on self-prepared titanic silicate ion-exchange plates with 0.4 M ammonium oxalate – 2.2 M aqueous ammonia 1:1. Detection of Cr (VI) by spraying with a saturated solution of diphenyl-carbazide in iso-propanol. Densitometry at 545 nm.

J. Liq. Chromatogr. Relat. Technol. 29, 2009-2018 (2006). TLC of 37 thiophosphorylglycinamide derivatives on silica gel, alumina, and silica gel impregnated with paraffin oil, in sandwich chambers at 4-5 °C with 11 ternary mobile phases from n-pentane - benzene - acetone with different composition. Detection by exposure to iodine vapor. Determination of the free energy of adsorption, the surface area of adsorption and the molecular lipophilicity of the TPGA derivatives.

Indian J. Pharm. Sci. 68 (6),788-789 (2007). HPTLC of etorocoxib in dosage forms on silica gel with chloroform - methanol - toulene 2:1:2. The plate was scanned at 289 nm for quantitative evaluation. The hRf value of etorocoxib was 58. The method was linear in the range of 100 - 600 ng/spot.The method was validated for accuracy, precision and repeatability. It was found suitable for routine quality control of formulations.

J. Sep. Sci. 30, 708-712 (2007). HPTLC of icariin in the aerial part of Epimedium koreanum Nakai on silica gel with ethyl acetate – glacial acetic acid – formic acid – water 10:1:1:2. Quantitative determination by absorbance measurement at 270 nm. The LOD and LOQ for icariin were 66 and 215 ng/band, respectively. Results did not show statistical significance between HPLC and HPTLC.

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.