J. AOAC Int. 88, 1571-1577 (2005). TLC and HPTLC of narceine, morphine, codeine, thebaine, papaverine, and narcotine on silica gel with toluene - acetone - ethanol - 25% ammonia 20:20:3:1. Detection with Dragendorff’s reagent with sodium nitrite, densitometric evaluation at 520 nm. For UV-detection, Naturstoff reagent A (diphenylboric acid 2-amino ethyl ester) was used; quantitation by densitometry at 310 nm.

J. Planar Chromatogr. 19, 58-61 (2006). HPTLC of xanthohumol and isoxanthohumol on silica gel with toluene - dioxane - acetic cacid 77:20:3 in an unsaturated flat-bottomed chamber. Quantification by scanning at 368 nm. The detection limit was 2 ng per spot. The method was validated for precision, accuracy, and repeatability. The method is specific; a linear relationship was obtained between response (peak area) and amount of xanthohumol in the range of 7.7-77 ng per spot; the correlation coefficient was 0.997. Recovery at the three levels was found to be 119.1 %, 95.7 %, and 96.7 %, respectively. Instrumental presision and repeatability were 0.38 and 1.5 %, respectively. Intra-day and Inter-day precision were 1.7 and 2.3 %, respectively.

J. Pharm. Biomed. Anal 39, 132-138 (2005). A simple, selective, precise and stability-indicating HPTLC method of analysis of curcumin both as a bulk drug and in formulations was developed and validated. HPTLC on silica gel with chloroform-methanol 37:3. This system was found to give compact spots of curcumin (Rf 0.48). Densitometric analysis of curcumin in the absorbance mode at 430 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r =0.996 and 0.994 via peak height and peak area, respectively, in the concentration range of 50-300 ng per spot. The method was validated for precision, recovery, robustness. The LOD and LOQ were 8 and 25 ng per spot, respectively. Curcumin was subjected to acid and alkali hydrolysis, oxidation and photodegradation.

J. Planar Chromatogr. 19, 223-227 (2006). HPTLC of leuprolide acetate (a synthetic nonapeptide analog) on silica gel after prewashing with chloroform - methanol 1:1 using five-step isocratic incremental multiple development with ethyl acetate - methanol - 25 % ammonia. Detection under UV light at 254 and 280 nm. Quantitation by reflectance scanning at 280 nm.

VI. Separation and determination of cadmium. J. Planar Chromatogr. 19, 246-250 (2006). TLC of cadmium on titanium silicate ion-exchange plates in a twin-trough chamber (without chamber saturation) with ammonium buffer of pH 10 (5.354 g ammonium chloride and 42.5 mL ammonia solution in 100 mL water). Quantitation by scanning in absorbance mode at 390 nm after deivatization with a saturated solution of sodium sulfide and at 530 nm after deivatization with a mixed solution of 2,2’-bipyridine and iron(II) sulfate.

J. Planar Chromatogr.19 , 282-287 (2006). HPTLC of ajmaline, ajmalicine, and reserpine on silica gel, prewashed with methanol, in an unsaturated twin-trough chamber with toluene - methanol 19:6. Detection by dipping in Dragendorff’s reagent. Quantitative determination by absorbance measurement at 520 nm.

J. Sep. Sci. 28, 1566-1576 (2005). HPTLC of itopride (subjected to acid and alkaline hydrolysis, oxidation, dry and wet heat treatment, UV and photo-degradation) on silica gel with toluene – methanol – chloroform 5:3:6 and 1 drop a of ammonia. Quantitative determination by absorbance measurement at 270 nm. The drug is well separated from its degradation products upon applying the two methods.

Anal. Sci. 22, 743-745 (2006). HPTLC of gatifloxacin and ornidazole on silica gel with n-butanol – methanol 8:1 and 1 drop ammonia with chamber saturation for 45 min. Quantitative determination by absorbance measurement at 302 nm. Linearity of determination of gatifloxacin is 100 – 500 ng and of ornidazole 250 – 1250 ng, with a correlation coefficient of more than 0.9850. The intra-day and inter-day coefficients of variation are found to be in the range of 0.68 - 2.58 % and 0.37 - 3.62%, respectively.