Anal. Chim. Acta 577 (1), 46-51 (2006). HPTLC of trigonelline in herbal extracts and in pharmaceutical dosage forms on silica gel with n-propanol - methanol - water 4:1:4. Quantitative determination by absorbance measurement at 269 nm. Linearity was between 100 - 1200 ng/spot (via peak area) and the correlation coefficient was 0.9991. The trigonelline content of herbal extracts quantified and estimated from the formulation was found to be well within limits (± 5 %) of the labeled content of the formulations. The method is reproducible and selective for the estimation of trigonelline by statistical analysis of the data.

J. Planar Chromatogr. 22, 157-161 (2009). Safed musli is the common name for Chlorophytum borivilianum, whereas shatavari is Asparagus racemosus, both of the liliaceae family. HPTLC of saponins and sapogenins on silica gel with chloroform - methanol - water 32:25:5 for saponins and with petroleum ether - ethyl actate 4:1 for sapogenins. Detection of saponins by spraying with anisaldehyde reagent and with Ehrlich’s reagent, followed by densitometric analysis at 620 and 510 nm. Detection of sapogenins by spraying with Liebermann Burchard reagent, followed by densitometric analysis at 580 nm.

Abstract No. 9145, IHCB (2009). Terminalia chebula (an important constituent of Triphala, a popular ayurvedic formulation) was standardized for gallic acid content by HPTLC on silica gel with toluene - ethyl acetate - formic acid 10:10:3. The hRf value of gallic acid was 45. Quantitative determination by absorbance measurement at 254 nm. The method was linear in the range of 150-550 ng/spot. Hydroalcoholic extracts of the fruit pulp contained 10.5 mg/g gallic acid.

Anal. Chim. Acta 598 (2), 312-317 (2007). TLC of paroxetine hydrochloride on silica gel with butanol - acetic acid - water 16:4:1. The hRf value of paroxetine HCl was 48 and separation from the degradation products (produced by acid and alkali hydrolysis, oxidation and photodegradation) was good. Quantitative determination by absorbance measurement at 295 nm. The linearity was in the range of 300 - 1500 ng/spot and the correlation coefficient was 0.9903. The limit of detection and quantitation was 50 and 150 ng/zone, respectively.

J. AOAC Int. 92, 725-729 (2009). HPTLC of acrylamide extracted from coffee samples on silica gel with ethyl acetate - tert. butyl methyl ether 4:1 in a twin trough chamber or automatic developing chamber. Pre-chromatographic in situ derivatization of the extracts (applied as area) by overspraying with dansulfinic acid produced the fluorescent dansylpropanamide band. Quantitative determination by fluorescence measurement at 254/>400 nm. The limit of quantification was 48 µg/kg. The linearity over the whole procedure showed determination coefficients between 0.9995 and 0.9825 (n = 6). The within-run precision (%RSD, n = 6) of the chromatographic method was 3%. Commercial coffee samples analyzed showed acrylamide contents between 52 and 191 µg/kg, which was in correlation with amounts reported in publications.

60th Indian Pharmaceutical Congress PG-262 (2008). HPTLC of withaferin A in Ashwagandha on silica gel aluminum layer with toluene - ethyl acetate - formic acid 5:5:1. Quantitative determination by absorbance measurement at 214 nm. The chromatograms of the tablet formulation showed a zone corresponding to standard withaferin A (hRf value 37) indicating the presence of the same in the herbal formulation. Linearity was in the range of 50-500 ng/spot. The concentration of withaferin A was 8.07 µg/tablet and 0.00134 % w/w in the tablet formulation.

J. AOAC Int. 92, 779-784 (2009). HPTLC of psoralen and plumbagin and extracts of ayurvedic polyherbal oil formulations on silica gel at 22 °C and 55 % humidity with toluene - ethyl acetate 3:1 in a twin trough chamber with chamber saturation. UV spectra were recorded from 200 to 600 nm; densitometric measurements were performed at 302 nm (for psoralen) and 275 nm (for plumbagin).

J. Chromatogr. Sci. 48 (1), 45-48 (2010). HPTLC of ambroxol hydrochloride on silica gel with methanol - triethylamine 2:3. The hRf value of ambroxol was 53. Quantification by absorbance measurement at 254 nm. Linearity was given in the range of 100-1000 ng/spot with r2 = 0.9966 (via peak area). The limits of detection and quantitation were 10 and 30 ng/spot, respectively. Ambroxol hydrochloride was susceptible to degradation under oxidation and thermal stress conditions. The method is suitable for purity testing of the drug as it detects the related impurities.