J. Planar Chromatogr. 24, 232-235 (2011). HPTLC of darunavir ethanolate in tablets on silica gel, prewashed with methanol, with toluene - ethyl acetate - methanol 7:2:1 in a twin-trough chamber lined with filter paper and saturated with mobile phase for 30 min at room temperature (25 +/- 2 °C). Quantitative determination by densitometry in absorbance mode at 267 nm. The hRf of darunavir ethanolate was 47. Linearity was between 250 and 1750 ng/band with r = 0.9994. The limits of detection and quantification were 15 and 46 ng/band, respectively. The intra-day and inter-day precision was (%RSD, n = 6) between 0.5-0.9 % and 1.1-1.3 %. Recovery (n = 6) was 99.3-101.2 %.

J. Planar Chromatogr. 24, 257-263 (2011). HPTLC of hydrophilic and lipophilic constituents of Salvia miltiorrhiza and standards protocatechuic acid and aldehyde, salvianolic acid A and B, dihydrotanshinone I, rosmarinic acid, caffeic acid, cryptotanshinone, tanshinone II A, tanshinone I, and miltirone on silica gel with dichloromethane - ethyl acetate - formic acid 11:12:5 for the first development and petroleum ether - ethyl acetate - cyclohexane 15:11:14 for the second development with chamber saturation for 30 min. The first mobile phase separated the hydrophilic constituents salvianolic acid B, salvianolic acid A, rosmarinic acid, caffeic acid, protocatechuic acid, and protocatechuic aldehyde. Detection under UV light at 254 and 365 nm. After documentation the plates were placed in a second chamber and development with the low polarity mobile phase which separated dihydrotanshinone I, cryptotanshinone, tanshinone I and II A, and miltirone. Detection under UV light at 254 and 365 nm. Quantitative determination by densitometry in absorbance mode at 260 or 290 nm. The linear range was between 0.1-0.3 and 0.7-8.3 µg/zone. Instrumental precision was less than 4 % (n = 6). Precision on one plate was below 5 % (n = 6) and on different plates below 14 %. Depending on the substance, the limits of detection and quantification were between 14-22 and 69-276 ng/zone, respectively. The repeatability (n = 6) was between 1.3-3.4 %. Some of the compounds had similar hRf values: for rosmarinic acid 44, for salvianolic acid 43, for caffeic acid 49, for protocatechuic acid 49, for dihydrotanshinone 65 and for cryptotanshinone 63. Additional detection by spraying with 5 % sulfuric acid in ethanol.

Research Journal of Pharmaceutical, Biological and Chemical Sciences 2(1), 6-11 (2011). HPTLC of tolterodine tartarate on silica gel with acetonitrile - water - formic acid 50:50:3 with chamber saturation for 15 min. Quantitative determination by densitometry in absorbance mode at 281 nm. The content of tolterodine tartarate in the formulation was calculated and found to be 99.1 %. The recovery (by standard addition) was between 99.1-100.1 %. LOD was 21 and LOQ 53 ng/zone. The intra-day and inter-day precisions (%RSD) were 0.05 and 0.08 %, respectively.

A new approach in forensic analysis. J. Planar Chromatogr. 24, 108-112 (2011). HPTLC of ditalimfos, edifenfos, and tolclofos-methyl on silica gel, prewashed with methanol, with n-hexane - acetone 9:1 in a twin-trough chamber with saturation. Quantitative determination by densitometry in absorbance mode at 254 nm, the wavelength of maximum absorption for all three fungicides. The hRf values of all three organophosphorus fungicides increased with increasing contents of acetone in the mobile phase.

J. Ethnopharmacol. 137, 341-344 (2011). HPTLC of quercetin (1) and kaempferol (2) in the leaves of Argyreia speciosa on silica gel with toluene - ethyl acetate 93:7. Quantitative determination by absorbance measurement at 254 nm. The hRf values of (1) and (2) were 32 and 75, respectively and their amount was found to be 0.6 % and 0.2 %, respectively.

Journal of Pharmacy Research 4(5), 1353-1355 (2011). HPTLC of methanolic extracts of Aegle marmelos fruit pulp on silica gel with toluene - ethyl acetate - glacial acetic acid 70:30:1. Densitometric quantification of marmelosin at 310 nm. The method was linear in the range of 50-350 ng/band. The method was used to determine the marmelosin content of pulp, unripe pulp, seeds, leaves, rind, outer stain and inner stain.

J. AOAC Int. 95, 992-1009 (2012). In his profound 22nd planar chromatography biennial review, the author presented the most important advances published between November 1, 2009 and November 1, 2011. The excellent review covered different aspects such as history, student experiments, books, reviews, theory and fundamental studies, chromatographic systems, apparatus and techniques, as well as quantitative analysis with a broad range of applications such as analysis of pharmaceuticals, herbal medicines, and dietary supplements, biological and clinical samples, foods and beverages, environmental samples and chemicals.

J. Planar Chromatogr. 25, 314-319 (2012). HPTLC of 4-odemethylpodophyllotoxin (1), podophyllotoxin (2), kaempferol (3), podophyllotoxone (4), and deoxypodophyllotoxin (5) in the rhizomes of Podophyllum hexandrum on silica gel with toluene - ethyl acetate 2:1 + 1 drop glacial acetic acid. Quantitative determination by absorbance measurement at 254 nm. Linearity was in the range of 1-8 µg/band for (1), (2) and (4) and 2-10 µg/band for (3) and (5). The intermediate/inter-day/intra-day precision was below 2 %. Average recovery for all (1) to (4) were between 96.4 and 101.8 %.