J. Planar Chromatogr. 22, 367-369 (2009). HPTLC of triterpenoids (alpha- and beta-amyrin, oleanolic acid) on silica gel prewashed with methanol and dichloromethane, with dichloromethane - ethyl acetate 37:3. in a horizontal chamber saturated for 15 min. Detection by spraying with 8 % sulfuric acid in ethanol and heating at 105 °C for 3 min. Evaluation in daylight and under UV 366 nm. Quantitative determination by absorbance measurement at 520 nm.

Drug Standards of China 9 (2), 144-146 (2008). TLC of nisoldipine silica gel with chloroform - acetone - triethylamine - water 90:5:1. Detection under UV 254 nm. Semiquantification of impurities by comparison of spots. The method was successfully used for the quality control of real life samples.

J. Planar Chromatogr. 23, 193-197 (2010). HPTLC of ochratoxin A, aflatoxin B1, G1, B2, and G2 on silica gel with t-butyl methyl ether - water - methanol - cyclohexane 48:1:2:1 in an unsaturated horizontal developing chamber and on RP18 with methanol - 4 % aqueous zinc sulfate solution - ethyl methyl ketone 5:5:1. After development the silica gel plate was dipped for 2 s in silicone oil - hexane 1:2 which enhanced aflatoxin fluorescence by a factor of 2 and ochratoxin A fluorescence by a factor of 3-10. RP18 plates were developed to a distance of 75 mm in an unsaturated vertical chamber. Averaged densitograms were obtained in the emission wavelength range from 445 to 485 nm. Sample pretreatment was by modified QuEChERS (Quick, Easy; Cheap, Effectice, Rugged, Safe) extraction with tetahydrofuran or acetone. Linearity was in the range of 3 to 100 pg/zone for aflatoxins B2 and G2, 10 to 350 pg/zone for aflatoxins B1 and G1, and 0.25 to 2.5 ng/zone for ochratoxin A. LOQ for the aflatoxins were between 13 and 35 pg/zone (equivalent to to 1.5 and 2.5 ppb); for ochratoxin A it was 970 pg/zone (56 ppb).

Abstract No. F-159 61st IPC (2009). HPTLC of telmisartan and amlodipine besylate on silica gel with tetrahydrofuran - dichloroethane - methanol - 25 % ammonia 30:10:5:2. Both compounds were well resolved with hRf values of 22 and 45 for telmisartan and amlodipine besylate respectively. Densitometric evaluation at 326 nm. The method was found to be linear in the range of 1200-7200 ng/band for telmisartan and 400-1400 ng/band for amlodipine besylate.

Indian Drugs 47(2), 71-74 (2010). HPTLC of irbesartan and hydrochlorothiazide on silica gel with acetone - chloroform - ethyl acetate - methanol 6:6:6:1. The plates were preconditioned for 10 min in a saturated chamber prior to development. The hRf value of irbesartan was 27 and of hydrochlorothiazide 37. The linearity was 1500-9000 ng/band and 125-750 ng/band for irbesartan and hydrochlorothiazide respectively. The average recovery for both drugs was 99.4-99.5 %.

J. Agric. Food Chem. 58, 4939-4944 (2010). HPTLC of azadirachtin (1) and salannin (2) in the seeds of Azadirachta indica on silica gel with hexane - ethyl acetate1:3. Quantitative determination by absorbance measurement at 220 nm. The hRf values of (1) and (2) were 18 and 30, respectively. Linearity was between 50 and 200 ppm for both (1) and (2). Recovery was 99.9 % for (1) and 99.3 % for (2). The intermediate precision was 88.5 % and 87.5 % for (1) and (2), respectively (n=3). The HPTLC and HPLC methods gave comparable results.

Encyclopedia of Chromatography Third Edition 1, 2111-2115 (2009). The author describes the sample preparation methods prior qualitative and quantitative analysis by TLC and HPTLC. Classical extraction and clean-up methods include liquid-liquid extraction and soxhlet extraction. Modern methods such as solid phase extraction (SPE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE) and immunoaffinity (IA) extraction and clean-up are also described.

International Journal of ChemTech Research 1(4), 1122-1128 (2009). TLC on silica gel with toluene - ethyl acetate 3:1. The hRf value of the furanocoumarin psoralen was 47. Densitometric evaluation at 299 nm. The method was linear in the range of 10-100 ng/band. The average recovery was 99.7 %.