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.

J. Planar Chromatogr. 23, 315-319 (2010). HPTLC of polyphenols (extracted from Quercus robur) and quercetin, chlorogenic acid, gallic acid, and rutin as standards on silica gel with ethyl acetate - water - formic acid 87:3:10 in an unsaturated twin-trough chamber. Detection by spraying with 1 % 2-aminoethyl diphenylborinate (natural products reagent) followed by 2 % polyethylene glycol 4000 solution as well as by spraying with 2 % phosphomolybdic acid reagent followed by heating at 120 °C for 5 min. Evaluation by densitometry in absorption mode at 700 nm.

J. AOAC Int. 93, 787-791 (2010). HPTLC of omeprazole on silica gel with chloroform - methanol 9:1 in a twin-trough chamber after saturation for 20 min. Quantitative determination by absorbance measurement at 302 nm. The hRf value of omeprazole was 39. Linearity was between 50 and 3000 ng/band. The intra-day and inter-day precision was 0.4-0.5 and 0.8-0.9 % (n = 2). The recovery was 98.4-99.1 %. LOD and LOQ were 8 and 24 ng/zone, respectively.

J. Planar Chromatogr. 24, 520-523 (2011). HPTLC of streptomycin and amoxicillin, ampicillin, cefixime, cephalexin, cloxacillin, co-trimoxazole, doxycycline, erythromycin, gentamycin, metronidazole, tetracycline on titanium(IV) silicate coated plates with 0.5 M potassium bromide and ethanol 9:1 in a twin-trough chamber. Detection by spraying with a fresh 2 % solution of sodium carbonate and 5 % sodium nitroprusside dihydrate in 1 % acetaldehyde 1:1 or iodine solution (2 g iodine and 3 g potassium iodide in 100 mL water). Quantitative determination by densitometry in absorbance mode at 359 nm. The recovery was 97.9 %. LOD and LOQ were 2 and 12 ng/zone, respectively.

J. Planar Chromatogr. 24, 218-221 (2011). HPTLC of alfuzosin hydrochloride (ALF) and dutasteride (DUTA) in the bulk drug and in a tablet formulation on silica gel with toluene - methanol - dichloromethane 6:1:1 + 1 drop triethylamine. Quantitative determination by densitometry at 247 nm. The hRf of ALF was 46 and of DUTA 65. Linearity was between 300-600 ng/band for ALF and 500-100 ng/band for DUTA. LOD and LOQ were 100 and 200 ng/band for ALF and 300 and 400 ng/band for DUTA. Precisions (%RSD) for repeatability of application were 1.8 and 1.5 % for ALF and 1.5 and 1.4 % for DUTA. The inter-day and intra-day precision (%RSD, n = 6) was 1.0 and 0.9 % for ALF and 1.7 and 0.8 % for DUTA, respectively. Recovery (by standard addition) was between 98.9-101.6 % for both compounds.

J. AOAC Int. 93, 811-819 (2010). HPTLC of olanzapine on silica gel (prewashed twice with methanol) with methanol - ethyl acetate 4:1 in a twin-trough chamber saturated for 20 min at 25 +/- 2 °C. Quantitative determination by densitometry in absorbance mode at 285 nm. The hRf was 35. Linearity was between 100 and 600 ng/band for olanzapine. LOD was 24 ng/band and LOQ 91 ng/band. The average recovery (n = 6) was 100.4 %. The %RSD of intra-day and inter-day precision (n = 5) was between 0.2-1.4 %.

J. Liq. Chromatogr. Relat. Technol. 32, 2437-2450 (2009). HPTLC calliterpenone (1) and calliterpenone monoacetate (2) in the leaves of Callicarpa macrophylla on silica gel with methanol - water 9:11. Quantitative determination by absorbance measurement at 210 nm. The hRf values of (1) and (2) were 43 and 73, respectively. Linearity was between 1-5 µg/zone for (1) and (2). LOD and LOQ were 230 and 780 ng/zone for (1) and 220 and 730 ng/zone for (2). Intra-day and inter-day precisions ranged between 1.3-1.7 % for (1) and 1.1-1.7 % for (2). Recoveries (by standard addition) were between 97.5-100.8 % for both.