J. Planar Chromatogr. 22, 127-131 (2009). HPTLC of 6-gingerol, extracts of Suprabha and market samples of ginger on silica gel (prewashed with methanol) with n-hexane - acetone 18:7 in a twin trough chamber saturated for 4 min at 20 +/- 4 °C and 36 +/- 3 % relative humidity. Quantitative determination by absorbance measurement at 286 nm. The limit of detection and quantification was 40 and 150 ng/band, respectively.

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.

Rapid Commun. Mass Spectrom. 23, 2711-2723 (2009). HPTLC in combination with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used for the analysis of complex lipid mixtures. For the separation of lipids one-dimensional HPTLC on silica gel aluminum foil was used with a two-phase mobile phase. The combination with MALDI-MS allowed the identification of 70 distinct lipid species and the analysis of even minor lipid classes from only very small volumes of human plasma (50 µL).

Acta Chromatographica 21 (1), 29-38 (2009). Evaluation of different TLC systems for analysis of 21 amino acids in biological tissues and fluids. Detection by derivatization with ninhydrin reagent, and determination of Rf values by slit-scanning densitometry. The five most suitable systems were cellulose and silica gel plates developed with either 2-butanol - pyridine - acetic acid - water 39:34:10:26 or 2-butanol - pyridine - 25 % ammonia - water 39:34:10:26, and ion exchange plates developed with citrate buffer of pH 3.3. Detection with ninhydrin allowed the identification of all amino acids except for leucine and isoleucine in complex mixtures. Quantification is possible as well if the amino acid of interest is well separated from adjacent components of the mixture. The method is illustrated with example chromatograms on cellulose HPTLC layer showing the identification and separation of amino acids in snail tissue samples.

Abstract No. F-309, 61st IPC (2009). HPTLC of olopatadine HCl on silica gel with methanol - chloroform - 25 % ammonia 80:20:1. The hRf value was 46. Quantitative determination by absorbance measurement at 301 nm. The method was linear in the range of 100-900 ng/band.

60th Indian Pharmaceutical Congress PA-202 (2008). HPTLC of allyl disulphide (an active ingredient of Allium sativum, garlic) on silica gel with n-hexane. The hRf value was 52. Quantitative determination by absorbance measurement at 298 nm. The linearity range was 200-1200 ng/spot. Several polyherbal formulations containing garlic were analyzed with the proposed method using allyl disulphide as marker.

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.

Abstract No. F-260, 61st IPC (2009). HPTLC of cefixime and cloxacillin on silica gel, prewashed with methanol, with n-butanol - methanol - water - formic acid 80:60:40:3. The hRf values were 28 and 45 for cefixime and cloxacillin, respectively. Quantitative determination by absorbance measurement at 293 nm for cefixime and 343 nm for cloxacillin. The linearity range was 150-600 ng/band for both compounds.