Chinese J. Pharm. Anal. (3), 547-553 (2014). Rhizoma Cimicifugae is a medicinal herb and one of the main ingredients of TCM preparations for the treatment of measles, sore mouth and throat, rashes, chronic diarrhea etc. For quality control, TLC of the extracts of the drug sample on silica gel with the lower phase of chloroform – methanol – water below 10 °C, detection under UV 366 nm revealed 9 pale blue zones. Detection by spraying with a freshly prepared solution of vanillin – sulfuric acid – acetic acid 1:10:1000 followed by heating at 105 ˚C until the zones are visible under UV 366 nm, this detection mode revealed 16 zones of different color. The resulting images were converted to digital profiles to carry out similarity and two-dimensional clustering analysis. The main components were identified using QTofMS with cimifugin, prim-O-glucosylcimifugin, 27-deoxyactein, and ferulic acid as references. Based on the fingerprints the genuine drugs were easily differentiated from adulterant drugs.

seed (Takhmaria). J. Planar Chromatogr. 29, 216-220 (2016). HPTLC of apigenin in the seeds of Ocimum basilicum on silica gel with toluene – acetone – formic acid 5:4:1. Quantitative determination by absorbance measurement at 340 nm. The hRF value of apigenin was 71. Linearity was in the range of 100-600 ng/zone. Intermediate precisions were below 0.5 %. The LOD and LOQ were 4 and 12 ng/zone. Recovery was between 98.5 and 100.6 %.

J. Chromatogr. Sci. 52 (9), 1089-1094 (2014). HPTLC of the anticancer compound nimbolide in different parts of Azadirachta indica and its dosage form on silica gel with n-hexane – ethyl acetate – acetic acid 30:20:1 (migration distance 68 mm, chamber saturation time 2 min), detection by spraying with 5 % sulfuric acid in methanol, quantification after absorption measurement at 515 nm. Validation by investigation of the (A) hRf value of nimbolide (43), (B) linearity range (200–1400 ng/zone, r2=0.99968), (C) LOD (70 ng/zone) and LOQ (200 ng/zone), (D) recovery (97.5 %, n=3), and (E) specificity (comparison of hRf value and UV/vis absorption spectrum with the standard).

J. Planar Chromatogr. 29, 417-422 (2016). HPTLC of kaempferol (1), quercetin (2), and gallic acid (3) in the herb Euphorbia humifusa on silica gel with chloroform – ethyl acetate – formic acid 26:22:5. Quantitative determination by absorbance measurement at 300 nm for (3) and 400 nm for (1) and (2). The hRF values for (1) to (3) were 18, 36 and 48, respectively. Linearities ranged 168-448 ng/zone for (1), 183-488 ng/zone for (2) and 179-476 ng/zone for (3). The intermediate precision was below 3.3 % (n=6). The LODs and LOQs were 16 and 53 ng/zone for (1), 7 and 23 ng/zone for (2) and 8-23 ng/zone for (3), respectively. Average recoveries were 96.1 % for (1), 98.3 % for (2) and 96.6 % for (3).

Planta Medica 82 (16), 1395-1402 (2016). The hexane – ethyl acetate subfraction of the ethyl acetate fraction of an ethanolic Tabebuia roseoalba leaf percolation extract was subfractioned on a silica gel column with 42500 mL of a gradient of hexane, ethyl acetate, and methanol. For monitoring, TLC on silica gel with hexane – ethyl acetate 1:1, detection with anisaldehyde sulfuric acid reagent. Two fractions that gave only one visible zone on TLC, were identified by NMR as mixtures of stigmasterol and sitosterol, and of alpha- and beta-amyrins, respectively.

Planta Medica 83(03/04), 300-305 (2017). Preparative TLC on 1) RP-18 phase with methanol – water, in several proportions from 2:1 to 9:11 and on 2) silica gel with dichloromethane – ethyl acetate, from 5:1 to 10:3 was applied to purify eight phenylethylchromones from subfractions of a methanolic extract of Aquilaria filaria agarwood. Preparative TLC on silica gel with n-hexane – ethyl acetate 2:1 was also used to separate the products of one of these chromones (2-(2-hydroxy-2-phenylethyl)-4H-chromen-4-one) with the (S)- and (R)-MTPA-Cl (α-methoxy-α-trifluoromethyl-phenylacetyl-chloride) needed for the Mosher ester method for asymmetric carbon configuration, allowing, after NMR, the determination of the chromone as an uneven mixture of R- and S-enantiomers (4:1). The enantiomer separation was done after derivatisation into diastereoisomers (no chiral separation).

J. Planar Chromatogr. 30, 181-187 (2017). HPTLC of guggulsterones E (1) and Z (2) in a polyherbal formulation containing Commiphora Muku on silica gel with toluene – ethyl acetate 4:1. Quantitative determination by absorbance measurement at 251 nm. The hRF values for (1) and (2) were 34 and 41. Linearity was between 0.2 and 1.2 μg/zone. LOD and LOQ were 43 and 132 ng/zone for (1) and 39 and 120 ng/zone for (2), respectively. The intermediate precision was below 2 % (n=3). Average recovery was 94.4 % for (1) and 97.7 % for (2).

Food Chem. 239, 831-839 (2018). HPTLC of saffron on silica gel with 1-butanol – acetic acid – water 4:1:1. Qualitative identification at UV 254 nm. The hRf values of the nine detected zones (crocins and picrocrocin derivatives) were 19, 29, 43, 56, 63, 67, 80, 85, and 96. Captured images were imported to the MATLAB program for pattern recognition and discrimination between different saffron samples on the basis of their soil electro-conductivity values as indicator of soil salinity. The data pre-processing included elimination of chromatographic artifacts such as baseline drifts and spot misalignment.