J. AOAC Int. 91, 1387-1396 (2008). HPTLC on silica gel with chloroform - methanol 9:1 in the first direction for curcumin, demethoxycurcumin, bis(demethoxy)curcumin, and the synthetic dye metanil yellow, and with toluene - hexane - acetic acid 50:50:1 for sudan I and sudan IV in the second direction. Quantitative determination by absorbance measurement at 420 nm for curcumin and metanil yellow, at 491 nm for sudan I, and at 520 nm for sudan IV.

60th Indian Pharmaceutical Congress PA-204, (2008). HPTLC of carvedilol on silica gel with methanol - ethyl acetate 13:7. The hRF was 49. Quantitative determination by absorbance measurement at 242 nm. Linearity was between 200-1000 ng/spot. The recovery was 98-102 %. The method was suitable for routine quality control of the drug in formulation.

J. AOAC Int. 91, 750-755 (2008). HPTLC of acetylsalicylic acid and clopidogrel bisulfate ((alphaS)-alpha-(chlorophenyl)-6,7-dihydrothieno[3,2-c]pyridine-5-(4H)-acetic acid methyl ester) on silica gel using ethyl acetate - methanol - toluene - acetic acid 50:10:40:1. Quantitative determination by absorbance measurement at 235 nm.

60th Indian Pharmaceutical Congress PA-199, (2008). HPTLC of trifluoperazine and hydrochloride and chlordiazepoxide on silica gel with carbon tetrachloride - acetone - triethylamine 12:6:1. Quantitative determination by absorbance measurement at 262 nm. The method was linear in the range of 20-280 ng/spot and 50-700 ng/spot for trifluoperazine HCI and chlordiazepoxide. The method was suitable for routine quality control of combined dosage form.

Chromatographia 70 (1-2), 305-308 (2009). Description of color channel selection, three-dimensional visualization, and acquisition time of computerized image analysis for one-dimensional planar separation, known as computerized image analysis or video densitometry. This is an efficient, low-cost technique for quantitative and qualitative analysis of planar separations, e.g. planar chromatography and gel electrophoresis. The image of the TLC plate is captured in black and white, then the proper color channel of the image is selected in order to enhance the signal-to-noise ratio. To facilitate image evaluation a three-dimensional visualization of the planar image was applied by use of OpenGL technology. It was found that the sensitivity is increased by use of longer acquisition times whereas linearity of quantitative analysis is reduced.

Acta Chromatographica 6, 7-14 (1996). HPTLC of fructose, glucose and sucrose on a channeled silica gel plate with concentration zone with acetonitrile - water 17:3 for three times (freshly prepared each time, taking 15 min per run) with chamber saturation for 10-15 min. Before, just the silica gel layer was impregnated by spraying with 0.10 M sodium bisulfate solution, and subsequently with citrate buffer (1:10 dilution of citrate buffer with water, pH 4.8), each followed by drying. Detection by spraying with 1-naphthol-sulfuric acid reagent, followed by heating at 100-110 °C for 5-10 min. Quantitative determination by absorbance measurement at 515 nm. The hRf values of fructose, glucose and sucrose were 47, 43, and 28, respectively, and selectivity regarding matrix was given. No zones other than the sugars were detected in sample chromatograms because of the selectivity of the detection reagent and the retention of the beverage components in the preadsorbent. Correlation coefficients (r) for linear regression of the calibration curves typically ranged from 0.90-0.99, with an average of 0.97. The precision in matrix was 2.5 % (n = 5). The mean reproducibility of the twofold sample analyses was 4 %, ranged between 0.45 % and 7.5 %. The accuracy of the method was 94.6 %, 97.0 % and 90.8 % for sucrose, glucose and fructose, respectively. Sugar concentrations in the samples ranged from 18.4-34.3 mg/mL.

J. Agric. Food Chem. 56, 4311-4319 (2008). HPTLC of the heterocyclic aromatic amines (HAA) most frequently found in fried meat: 2-amino-1-methyl-6-phenylimidazol[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazol[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 9H-pyrido[3,4-b]indole (norharman), and 1-methyl-9H-pyrido[3,4-b]indole (harman) using a previously validated method. Concentrations obtained by HPTLC were in a similar range as such obtained by HPLC with correlations of both methods between 0.8875 and 0.9751. The precision in meat matrix was between 7 and 49 % (HPTLC) and between 5 and 38 % (HPLC) at the very low µg/kg-levels formed during heating. Cost and time comparison showed that HPTLC is 4 times faster and 3 times less expensive than the HPLC reference method.

J. Planar Chromatogr. 21, 305-307 (2008). HPTLC of tramadol hydrochloride and chlorzoxazone on silica gel, prewashed with methanol, in a twin trough chamber, saturated for 10 min, with ethyl acetate - toluene - ammonia 35:15:1. Quantitative determination by absorbance measurement at 273 nm.