J. Planar Chromatogr. 33, 11-18 (2020). HPTLC of lutein in dietary supplements on silica gel with n-heptane – ethyl acetate 9:1. The part of the TLC chromatogram containing the zone visible in day light was cut off, followed by developing in the opposite direction with n-heptane – acetone – ethyl acetate 11:5:4. Quantitative determination by absorbance measurement at 450 nm. Linearity was between 90 and 500 ng/zone for lutein. Intermediate precisions were below 2 % (n=9). The LOD and LOQ were 50 and 90 ng/zone, respectively. Recovery rate was between 87 and 102 %.

J. Planar Chromatogr. 33, 51-57 (2020). HPTLCS (high-performance thin-layer chromatography scanning) of ethyl p-methoxycinnamate in the rhizome of Kaempferia galanga on silica gel with hexane - ethyl acetate 18:1. Quantitative determination by absorbance measurement at 309 nm. The hR_F value for ethyl p-methoxycinnamate was 29. Linearity was between 2 and 6 ng/zone. Intermediate precisions were below 2.4 % (n=3). Mean recovery rate was 100.1 %. Results were compared with a validated HPLC method and the HPTLCS method was more environmetnally friendly..

J. Planar Chromatogr. 33, 71-77 (2020). HPTLC of ledipasvir (1) and sofosbuvir (2) on silica gel with ethyl acetate - hexane - methanol  32:5:3. Quantitative determination by absorbance measurement at 256 nm. Linearity was between 60 and 1980 ng/zone for (1) and 45 and 3600 ng/zone for (2). Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 16 and 50 ng/zone for (1) and 13 and 40 ng/zone for (2), respectively. Mean recovery rate was 99.4 % for both (1) and (2).

J. Planar Chromatogr. 33, 79-87 (2020). HPTLC of velpatasvir (1) and sofosbuvir (2) on silica gel with chloroform - methanol 19:1. Quantitative determination by absorbance measurement at 265 nm. The hR_F values for (1) and (2) were 29 and 19, respectively. Linearity was between 5 and 50 µg/zone for (1) and 10 and 70 µg/zone for (2).  Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 3 and 5 µg/zone for (1) and 8 and 10 µg/zone for (2), respectively. Mean recovery rate was 100.2 % for (1) and 100.9 % for (2).

J. Planar Chromatogr. 33, 59-70 (2020). HPTLC of metformin (1), saxagliptin (2) and dapagliflozin (3) on silica gel with chloroform - methanol - water - acetic acid 740:260:50:1. Quantitative determination by absorbance measurement at 224 nm. The hR_F values for (1) to (3) were 14, 50 and 66, respectively. Linearity was between 30 and 350 µg/mL for (1), 140 and 1500 µg/mL for (2) and 50 and 600 µg/mL for (3).  Intermediate precisions were below 2 % (n=6). LOD and LOQ were 7 and 23 µg/mL for (1), 39 and 130 µg/mL for (2) and 14 and 47 µg/mL for (3), respectively. Recovery rate was between 98.9 and 100.5 % for (1), 99.2 and 100.5 % for (2) and 99.2 and 100.7 % for (3). Comparable results were obtained when compared with a HPLC method.

J. Planar Chromatogr. 33, 89-95 (2020). Thin-layer electrophoresis of inorganic anions F-, Cl-, Br-, I-, IO3-, IO4-, BrO3-, IO3-, Fe(CN)63- and Fe(CN)64- on (1) silica gel, (2) titanium (IV) tungstate and (3) admixture of silica gel and titanium (IV) tungstate 1:1 for 2 h at 100 V using 0.1 M oxalic acid, 0.1 M citric acid, 0.1 M tartaric acid, 0.1 M succinic acid and 0.1 M acetic acid as background electrolyte. Silica gel was effective in achieving binary, ternary and quaternary separations. The magnitude of migration was in accord with the order of lyotropic number.

J. of Chromatogr. Sci. 57 (8), 688 - 696 (2019). Tephrosia purpurea (L.) Pers., commonly known as “wild indigo”, is used in TCM to treat liver, spleen and kidney disorders. To investigate the seasonal effect on the quantity of its phytoconstituents lupeol, β-sitosterol and rotenone, analysis of the extracts from plant material collected in different seasons by HPTLC on silica gel with toluene - ethyl acetate - formic acid 9:1:1. The zones due to  β-sitosterol, rotenone and lupeol were observed at hRF 38, 45 and 52, respectively. Validation of the method in terms of precision, repeatability, specificity, sensitivity, linearity and robustness. The quantitative results obtained with this method showed that the content of these phytoconstituents varies from season to season. It was found that T. purpurea should not be collected in winter season for the preparation of therapeutic formulations because of the high content of rotenone, which is responsible for Parkinson’s disease and associated with heart failure, fatty liver and liver necrosis.

J. Chromatogr. A 1594, 190-198 (2019). Quality assessment of herbal drugs, e.g. Morus alba L. root bark (sāng bái pí; SBP), using a HPTLC/bioautography method. Identification of the most bioactive constituents with radical scavenging (DPPH radical assay) and antimicrobial activities (Bacillus subtilis, Escherichia coli) of 18 different M. alba samples, supported by UPLC–MS/MS analysis. Higher both radical scavenging and antimicrobial activities were found for plant materials collected from Serbia (11 samples) compared to samples provided from China (7 samples). Confirmation of geographically different samples and recognization of their main markers responsible for differences between Serbian and Chinese samples by principal component analysis (PCA). The developed procedure allowed not only for a fast chemical profiling of the investigated samples and their unambiguous identification, but also for the disclosure of major and minor bioactive constituents present in SBP.