Phytochem. Anal. 21, 219-223 (2010). HPTLC of safranal in saffron extract and in a safranal-loaded nanoparticle formulation on silica gel with n-hexane - ethyl acetate 9:1. Quantitative determination by absorbance measurement at 310 nm. The hRf of safranal was 51. Linearity was between 0.5 and 5.0 µg/zone. The intra-day and inter-day precisions were 1.08-2.17 and 1.86-3.47 %, respectively. LOD was 50 ng/zone while LOQ was 150 ng/zone. The average recovery was 99.9 %. The proposed method provides significant advantages in terms of greater specificity and rapid analysis.

czern and Brassica nigra L. Asian J. Chem. 22(7), 5349-5354 (2010). An HPTLC method is reported for estimation of sinigrin from seeds of Brassica juncea and Brassica nigra (Cruciferae). HPTLC of methanolic seed extracts on silica gel with ethyl acetate - methanol - water 6:2:1. Densitometric evaluation at 230 nm. The method was linear in the range of 400-1200 ng/band. Amounts of 0.43 and 1.55 % sinigrin were found in Brassica juncea and B. nigra, respectively. The method is suitable for routine quality control of herbal raw material.

J. Planar Chromatogr. 23, 406-410 (2010). TLC and OPLC of essential oil of thyme (thymol, carvacrol, and linalool as standards) on silica gel with chloroform (previously extracted with a 0.1 % aqueous solution of sodium hydrogen carbonate and dried on sodium sulfate to eliminate the stabilizer amylene, free hydrochloric acid, and chlorine) in an unsaturated chamber. Detection at 254 nm, by spraying with vanillin - sulfuric acid reagent (50 mg vanillin with 12 mL ethanol and 200 mL 98 % sulfuric acid) and heating to 70 °C for 10 min, and by use of the BioArena system. Quantitative determination by densitometry at 275 and 600 nm (dual-wavelength measurement).

International Journal of Green Pharmacy 3 (1), 47-17 (2009). HPTLC of caffeine on silica gel with ethyl acetate - methanol 9:1. Densitometric quantification at 274 nm. The method was linear in the range of 2-14 µg/band. The sample extracted with 5 % diethyl amine in water gave the maximum yield of caffeine (2.1 %). The proposed chromatography gave the best resolution with caffeine at an hRf value of 40. The method can be used for quality control of tea samples in respect of caffeine contents.

Phytochem. Anal. 21, 556-560 (2010). HPTLC of betulinic acid in the rhizomes of Nelumbo nucifera on silica gel with chloroform - methanol - formic acid 49:1:1. Detection by spraying with anisaldehyde - acetic acid - methanol - sulfuric acid 5:100:850:50 and drying at 50 °C for 10 min. Quantitative determination by absorbance measurement at 420 nm. The hRf of betulinic acid was 30. Linearity was between 2 and 10 µg/zone. Detection and quantification limits were 0.4 and 2.30 µg, respectively. The intra-day and inter-day precisions were 0.4 % and 0.3 % (n=3) respectively. Recovery (by standard addition) was 98.4 %.

62nd Indian Pharmaceutical Congress Abstract No. F-259 (2010). Health drinks usually contain several phytopharmaceuticals with immunomodulatory and antioxidant activities. TLC of gallic acid on silica gel with toluene – ethyl acetate – methanol – formic acid 15:15:1:4. The gallic acid content was established and the identity of the gallic acid zone in sample and standard was confirmed by UV spectra comparison.

J. Sep. Sci. 34, 749-760 (2011). HPTLC of (-)-epicatechin (1), (-)-epicatechin gallate (2), (-)-epigallocatechin gallate (3), caffeine (4), rutin (5), quercetin (6), gallic acid (7), ellagic acid (8), caffeic acid (9), and ferulic acid (10) in the leaves of green tea (Camellia sinensis) and guava (Psidium guajava) on silica gel with toluene – acetone – formic acid 5:4:1 for compounds (1) - (6) and toluene – ethyl acetate – formic acid – methanol 15:15:4:1 for compounds (7) - (10). Quantitative determination by absorbance measurement at 282 nm for compounds (1) - (6) and 285 nm for compounds (7) - (10). The hRf values of compounds (1) - (10) were 49, 37, 26, 60, 8, 66, 49, 34,62 and 70, respectively. Linearity was between 100-350 ng/band for compounds (1) - (5), 66.6-233.2 ng/band for compound (6) and between 50-300 ng/band for compounds (7) - (10). The limits of detection were found to be 60 ng/band for compounds (1) - (3), 30 ng for compounds (4), (5) and (8), 40 ng/band for compound (6), 20 ng/band for compound (7) and 10 ng/band for compounds (9) and (10). The limits of quantification were 100 ng/band for compounds (1) - (3), 60 ng/band for compounds (4) - (7), 30 ng/band for compounds (9) - (10), and 75 ng/band for compound (8). Inter- and intraday precisions were below 1.50 % and 2.84 %, respectively. Recoveries were found in the range of 95-100 %.

J. of Chromatogr. A 1218 (37), 6540-6547 (2011). New approach and application of highly automated planar chromatographic tools for powerful clean-up, called high-throughput planar solid phase extraction (HTpSPE), which is indispensable for preventing matrix effects in multi-residue analysis of pesticides in food by liquid and gas chromatography coupled to mass spectrometry, employing TLC to completely separate pesticides from matrix compounds and to focus them into a sharp zone, followed by extraction of the target zone by the TLC-MS interface, thus resulting in extracts nearly free of interference and free of matrix effects, as shown for seven chemically representative pesticides in four different matrices (apples, cucumbers, red grapes, tomatoes), and completion of clean-up of one sample in a manner of minutes. Regarding the clean-up step, quantification by LC–MS with mean recovery (against solvent standards) of 90–104% and relative standard deviations of 0.3–4.1% (n = 5) for two spiking levels of 0.1 and 0.5 mg/kg.