J. Planar Chromatogr. 24, 441-444 (2011). HPTLC of plant extracts and 17 polyphenolic compounds (apigenin, apigenin-7-glucoside, ellagic acid, hyperoside, isoquercitrin, kaempferol, kaempferol-3-glucoside, kaempferol-3-glucuronide, luteolin, luteolin-7-glucoside, methyl brevifolincarboxylate, myricetin, quercetin, quercetin-3-glucuronide, rutin, tiliroside, ellagic acid 3,3’-di-O-methyl ether 4-xylopyranoside) on silica gel (prewashed with methanol) with toluene - ethyl formate - formic acid 7:5:1 in an automatic developing chamber set with a twin-trough chamber at 22 °C and a relative humidity of 48 %. Detection under UV light at 254 and 366 nm, and at 366 nm after spraying with 1.0 % methanolic diphenylborinic acid 2-aminoethylester.

ex Schultes. J. Planar Chromatogr. 24, 388-393 (2011). HPTLC of p-hydroxybenzoic acid in the whole plant of Aerva lanata collected during summer, monsoon and winter on silica gel, prewashed with methanol, with ethyl actate - toluene 7:3 in a twin trough chamber. Detection under UV light at 254 nm. The hRf value of p-hydroxybenzoic acid was 73. Quantitative determination by densitometry at 252 nm. The calibration was linear in the range of 25-175 ng, with a regression coefficient of 0.9986. The %RSD for intra-day and inter-day precision was less than 2 %. The %RSD for the repeatability of sample application and measurement of area was 1.2 % and 0.9 %, respectively. The limit of detection and the limit of quantification was 0.5 and 1.4 ng, respectively. Recovery (by standard addition) was found to be 97.2 % (n = 3).

J. Planar Chromatogr. 24, 497-502 (2011). HPTLC of isoswertisin-5-O-beta-D-glucoside (1), swertiamarin (2), and swertisin (3) as biomarkers on silica gel with ethyl acetate - methanol - water 16:2:1 in a twin-trough chamber with saturation for 30 min. Quantitative determination by absorbance measurement at 287 nm. Linearity was between 25-75 µg/mL for (1), 200-600 µg/mL for (2), and 100-300 µg/mL for (3). The relative standard deviation for instrumental precision, intra-assay precision, and intermediate precision was below 2 %. The average recovery was 99.9 % for (1), 99.6 % for (2), and 99.1 % for (3). The hRf values were 32 for (1), 41 for (2), and 52 for (3). The limit of detection was 570 ng, 740 ng, and 300 ng for (1), (2), and (3), respectively.

Rapid Commun. Mass Spectrom. 26, 37-42 (2012). Blotting method to transfer analytes separated on wettable HPTLC plates to a hydrophobic RP-8 HPTLC plate. The hydrophobic RP-8 HPTLC plate was wetted with 500 mL methanol then left to evaporate until solvent saturation on the surface was no longer visible. Then the wet plate was placed over the hydrophilic HPTLC plate and pressure was applied to the plates for 10 min. The two plates were separated, and the dried RP-8 plate was analyzed using a liquid microjunction surface sampling probe in combination with electrospray ionization mass spectrometry (LMJ-SSP/ESI-MS). This method provides different means of expanding the utility of the LMJ-SSP approach into the analysis of wettable-phase HPTLC surfaces.

J. Planar Chromatogr. 24, 145-149 (2011). HPTLC of ticlopidine in the bulk drug and dosage form on silica gel, prewashed with methanol, with toluene - methanol 49:1. Quantitative determination by absorbance measurement at 240 nm. The hRf of ticlopidine was 60. Linearity was in the range 800-1500 ng/zone; the correlation coefficient was 0.999. LOD was 35 and 0.2 ng/band by peak height and peak area, respectively. Recovery was 98.5 % and 99.1 % by peak height and peak area, respectively. The inter-day and intra-day precision (%RSD, n = 3) was 0.9 % and 0.4 % via peak height and 0.6 % and 0.4 % via peak area.

J. Chil. Chem. Soc. 56, 702-705 (2011). HPTLC of lamivudine (1) and tenofovir disoproxil fumarate (2) in bulk drug and pharmaceutical dosage form on silica gel with chloroform - methanol - toluene 4:1:1. Quantitative determination by absorbance measurement at 265 nm. The hRf values of (1) and (2) were 27 and 51, respectively. Linearity was between 60-210 ng/zone for both. LOD and LOQ were found to be 20 and 40 ng/zone for (1) and 30 and 60 ng for (2). The intermediate/interday/intra-day precision was 0.6 % (n=6). Recovery (by standard addition) for (1) and (2) was between 98-102 %. The HPTLC method is suitable for routine analysis of lamivudine and tenofovir in pharmaceutical dosage form.

Acta Chromatographica 22 (4), 549-567 (2010). HPTLC of risperidone on silica gel with methanol - ethyl acetate 4:1. The hRf value of risperidone was 34. Quantitative evaluation by absorbance measurement at 285 nm. The linearity was in the range of 100-600 ng/band (r=0.9996), the LOD was 22 ng/band and the LOQ was 68 ng/band. The method was suitable for selective analysis of risperidone and was successfully used for estimation of the equilibrium solubility of risperidone, and for quantification of risperidone as the bulk drug in a commercially available preparation, in in-house developed mucoadhesive microemulsion formulations, and in solution.

J. of China Three Gorges Univ. Natural Sciences 33 (4), 92-95 (2011). TLC of extracts of Biyuan Pills on silica gel 1) for Magnolia liliiflora Desr. with dichloromethane - ethyl acetate 9:1, detection by spraying with 10 % sulfuric acid in ethanol and heating at 90 °C until the zones were detected; 2) for Xanthium sibiricum Patr., with chloroform - ethyl acetate - methanol - water - formic acid 3:10:2:2:2, detection by exposure to iodine vapor until the zones were detected; 3) for Lonicera japonica and Chrysanthemum indici flos, with toluene - ethyl acetate - formic acid - glacial acetic acid - water 1:15:1:1:2, detection under UV 365 nm.