Indian Drugs 42 (11), 731-734 (2005). Hydro-distilled volatile tea-tree oil of Melaleuca alternifolia was investigated by GC-MS, HPTLC, and X-Ray fluorescence. HPTLC on silica gel with toluene - ethyl acetate 93:7. Detection by spraying with anisaldehyde sulphuric acid reagent. Nine well-distinguished peaks were obtained.

L. Planar Chromatogr. 19, 135-138 (2006). HPTLC of nitrendipine on silica gel with n-hexane - ethyl acetate - acetone 6:3:2 in a horizontal chamber. Visualization under UV light. Densitometry was performed in absorbance mode at 335 nm. The calibration plot was constructed in the range 0.025 to 0.150 µg/µL (corresponding to 0.5-3.0 µg/spot) with good correlation (r2> 0.990). The method is also characterized by good precision and accuracy.

TrAC 21, 468-486 (2002). The article describes the valuable lessons learned from EU while funding a method-validation project (1996-2000) to meet European mycotoxin control in foodstuffs. It shows the performance characteristics of validated and official methods for aflatoxins, the selection and development of methods for validation, and the preparation of naturally contaminated mycotoxin test materials for validation studies. The authors put special emphasis on validation of TLC methods for mycotoxins for developing countries, as the main exporters to Europe of food and food products.

Acta Chrom. 12, 151-158 (2002). HPTLC of lutein in nutrition supplements on RP-18 (with concentration zone, pre-washed with dichloromethane – methanol 1:1) with petroleum ether – acetonitrile – methanol 1:2:2. All sample solutions and developing chambers were wrapped in aluminum foil to protect the labile pigment from photo-decomposition. Densitometry at 448 nm. Three products containing lutein as the free alcohol or dipalmitate ester plus other ingredients were analyzed.

J. Chil. Chem. Soc. 48, 71-73 (2003). HPTLC validation of carbamazepine in saliva samples on silica gel previously activated at 130 ºC for 20 min. Development over 5 cm in a saturated chamber with ethyl acetate – toluene – methanol 5:4:1. Detection by dipping in 60 % perchloric acid in ethanol – water 1:1, followed by heating at 120ºC for 7 min. Quantitative determination by fluorescence measurement at 366 nm. Linearity is between 0.5 and 15.0 ng per spot. The detection limit is 0.18 ng and the quantification limit is 0.54 ng. Precision: The analysis shows an intra-assay variation between 5.1 - 7.4 % and an inter-assay variation between 5.6 - 7.4 %. The method allows separation of carbamazepine from its main metabolites 10,11-dihydrocarbamazepine and carbamazepine-10,11-epoxide.

J. Planar Chromatogr. 19, 378-382 (2006). TLC and HPTLC of myricitrin on silica gel, pre-washed with methanol, in a horizontal chamber with chloroform -methanol - formic acid - water 10:4:1:0.95. Quantitative determination by absorbance measurement at 254 nm.

J. Liq. Chromatogr. Relat. Technol. 29, 219-227 (2006). HPTLC of selected sarsasapogenins (shataverin-IV and immunoside) on silica gel with ethyl acetate - methanol - water 75:13:5:10. Detection by spraying with ceric ammonium sulfate followed by heating at 100 °C for 5 min. Quantitation by scanning at 450 nm.

Indian J. Pharm. Sci. 68 (6), 790-793 (2007). HPTLC of carvedilol in bulk drug and pharmaceutical formulations, on silica gel with ethyl acetate - toluene - methanol 2:8:7. Quantitative absorbance measurement at 242 nm. The hRf value of carvedilol was 65. The method was found to be linear over the concentration range of 50-300 ng/spot with recovery of 98.3-101.1%.The method was validated for accuracy and precision. Comparison with an HPLC method showed the HPTLC method to be advantageous regarding sample throughput.