J. Planar Chromatogr. 34, 263-270 (2021). HPTLC of quetiapine fumarate (1) and its related genotoxic impurities 2-chloroaniline (2) and 2-aminodiphenylsulide (3) on silica gel with ethyl acetate - ethanol - n-heptane 5:1:4. Quantitative determination by absorbance measurement at 229 nm. The hRF values for (1) to (3) were 13, 57 and 76, respectively. Linearity was between 100 and 600 ng/zone for (1) and 10 and 60 ng/zone for (2) and (3). Intermediate precisions were below 2 %. The LOD and LOQ were 0.9 and 2.8 ng/zone for (1), 0.3 and 0.9 ng/zone for (2) and 0.2 and 0.5 ng/zone for (3), respectively. Recovery of the impurity in quetiapine fumarate ranged between 99 % and 101 %.

J. Planar Chromatogr. 34, 197-202 (2021). HPTLC of L‑proline (1) and L‑lysine (2) derivatives on silica gel with ethanol - toluene 2:3 in a horizontal chamber. Amino acids pre-chromatographic derivatization with 2-propanol - phenyl isothiocyanate - phosphate buffer pH 12 7:1:1. Detection by spraying with a solution of 4 % sodium azide, 0.5 % starch, pH 5.5, followed by exposure to iodine vapor for 20 s. Plates were scanned with an office scanner and the zones were converted to peaks by software. The hRF values for (1) and (2) were 32 and 67, respectively. Intermediate precisions were below 9 % (n=6). The LOD was 0.05 nmol/zone for (1) and 0.05 nmol/zone for (2). Recovery was between 94 and 104 % for (1) and 82 and 104 % for (2).

J. Planar Chromatogr. 34, 229-242 (2021). HPTLC of chlorthalidone (1) and metoprolol succinate (2) on silica gel with toluene - methanol - triethylamine 16:4:1. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 44 and 23. Linearity was between 200 and 1000 ng/zone for (1) and 800 and 4000 ng/zone for (2). Intermediate precisions were below 2 %. The LOD and LOQ were 29 and 88 ng/zone for (1) and 151 and 459 ng/zone for (2), respectively. Recovery was between 99.9 and 100.9 % for (1) and 100.4 and 101.6 % for (2).

J. Planar Chromatogr. 34, 279-283 (2021). HPTLC of linagliptin on silica gel with toluene - methanol 7:3. Quantitative determination by absorbance measurement at 294 nm. The hRF value for linagliptin was 91. Linearity was between 100 and 500 ng/zone. Intermediate precisions were below 2 % (n=3). The LOD and LOQ were 0.26 and 0.78 ng/zone, respectively. Recovery was between 99.1 % and 101.2 %.

J. Planar Chromatogr. 34, 243-252 (2021). HPTLC of dapagliflozin (1) and metformin (2) on silica gel with methanol - ethyl acetate - ammonium acetate 60:40:1. Quantitative determination by absorbance measurement at 220 nm. The hRF values for (1) and (2) were 79 and 31, respectively. Linearity was between 20 and 100 ng/zone for (1) and 500 and 2500 ng/zone for (2), respectively. Intermediate precisions were below 2 % (n=5). The LOD and LOQ were 3 and 10 ng/zone for (1) and 11 and 34 ng/zone for (2), respectively. Recovery was between 100.0 % and 101.6 % for (1) and 99.7 % and 101.1 % for (2).

J. Planar Chromatogr. 34, 211-215 (2021). HPTLC of acebutolol enantiomers on silica gel with acetonitrile - methanol - water 11:5:2. Detection by exposure to iodine vapor. The stationary phase with the chiral selector was prepared by mixing 25 g silica gel with 50 mL of a 50 mM solution of colistin sulfate, followed by drying and activation overnight at 60 °C. The LOD for each enantiomer of acebutolol was 12-15 μg/zone. Recovery was between 87 and 91 %.

J. Food Sci. 85, 1781-1792 (2020). HPTLC of scented (joha) rice and black rice variety on silica gel with chloroform - methanol 19:1 + 0.1 % formic acid and butanol - acetic acid - water 4:1:5. Detection by spraying with p-anisaldehyde and visualization under UV light at 200, 250 and 350 nm. The husk of the selected rice varieties contained the nonpolar metabolites whereas the seeds contain nonpolar as well as polar metabolites.

Sens. Actuators. B. Chem. 325, 128753 (2020). Leucomalachite green (1) and malachite green (2) and certain amount of highly dispersed potassium iodate titanium dioxide composites (0.1 M titanium butoxide was used as a precursor with 5 % potassium iodate solution to prepare KIO3-doped TiO2 nanoparticles). The sample was developed with chloroform - methanol 4:5. Detection by dipping into 5 % potassium iodine, followed by heating and then dipping into a zinc ion solution followed by heating at 80 °C. Linearity was in the range of 0.3–8.0 μg/mL for (1) and 0.1–4.0 μg/mL for (2), respectively. LOD and LOQ were 1.7 and 5.2 μg/kg for (1) and 0.9 and 2.7 μg/kg for (2), respectively.