J. Chromatogr. A 1525, 173-280 (2017). Presentation of a straightforward, selective and sensitive screening method for the determination of 16-O-methylcafestol (16-OMC) in roasted coffee, the characteristic diterpene exclusively present in Coffea canephora which is an excellent marker for Coffea canephora admixtures to Coffea arabica. HPTLC with fluorescence detection (HPTLC–FLD), using sudan IV as internal standard and a direct saponification with 10 % ethanolic potassium hydroxide solution, followed by solid-supported liquid extraction with petroleum ether. Selective derivatization of 16-OMC with 2-naphthoyl chloride and analysis by HPTLC–FLD on silica gel with cyclohexane – t-butyl methyl ether – formic acid 43:7:1. Quantitative determination of the enhanced fluorescence at 244/>320 nm. The LOD and LOQ was 5 and 14 mg/kg of 16-OMC in coffee, which allowed for the determination of Coffea canephora admixtures to Coffea arabica below 1 %. The recovery for blends of Coffea arabica with Coffea canephora was close to 100 %._x000D_

J. Planar Chromatogr. 31, 230-234 (2018). HPTLC of hypoxoside in the roots of Hypoxis hemerocallidea on silica gel with chloroform – methanol – water 35:15:1. Quantitative determination by absorbance measurement at 257 nm. The hRf value for hypoxoside was 30. Linearity was in the range of 0.02-1.80 µg/mL. The LOD and LOQ for hypoxoside were 0.51 µg and 1.65 µg/mL. (Note by the editor: It can not be true that the start of calibration is below the LOD by a factor of 25.) The intermediate precision was below 5 %. Average recovery was 84 %.

J. Planar Chromatogr. 31, 197-201 (2018). HPTLC of shatavarin IV in the roots of Asparagus racemosus on silica gel with ethyl acetate – methanol – water 15:3:2. Detection by spraying with anisaldehyde sulfuric acid reagent, followed by heating at 105 ºC for 5 min. Quantitative determination by absorbance measurement at 425 nm. The hRf value for shatavarin IV was 43. Linearity was in the range of 600-1800 ng/zone. The intermediate precision was below 2 % (n=3). The LOD and LOQ were 14 and 44 ng, respectively. Average recovery was 96.2 %.

J. Planar Chromatogr. 31, 235-242 (2018). HPTLC of lormetazepam on silica gel with acetonitrile – water 3:2. Quantitative determination by absorbance measurement at 241 nm. The hRf value for lormetazepam was 44. Linearity was in the range of 1.0-7.5 μg/zone. The intermediate precision was below 4 % (n=3). The LOD and LOQ were 0.26 and 0.77 μg, respectively. Average recovery was 100.9 %. Comparable results were obtained with a validated HPLC method.

J. Planar Chromatogr. 31, 429-436 (2018). HPTLC of _x000D_caffeic acid (1), ferulic acid (2), β-sitosterol (3), and lupeol (4) on silica gel with toluene – ethyl acetate – formic acid 85:15:1. Quantitative determination by absorbance measurement at 366 nm for (1) and (2) and 580 nm for (3) and (4). The hRF values for (1) to (4) were 14, 29, 48 and 63, respectively. Linearity ranged between 100-600 ng/zone for (1) and (2) and 200-700 ng/zone for (3) and (4). LOD and LOQ were 49 and 149 ng/zone for (1), 93 and 282 ng/zone for (2), 194 and 589 ng/zone for (3) and 36 and 109 ng/zone for (4), respectively. The intermediate precision was <2 % (n=6). Average recovery was 99.6 % for (1), 99.9 % for (2), 99.2 % for (3) and 99.5 % for (4).

J. Planar Chromatogr. 31, 383-388 (2018). HPTLC of cocaine hydrochloride (1) and levamisole hydrochloride (2) on silica gel with cyclohexane – toluene – diphenylamine 75:15:10. Quantitative determination by absorbance measurement at 230 nm. The hRF values for (1) and (2) were 24 and 48, respectively. Linearity was between 200 and 2400 ng/zone for (1) and 100 and 1200 ng/zone for (2). LOD and LOQ were 14 and 42 ng/zone for (1) and 6 and 19 ng/zone for (2), respectively. The intermediate precision was <2 % (n=6). Average recovery was 99.8 % for (1) and 99.9 % for (2).

J. Planar Chromatogr. 31, 265-271 (2018). HPTLC of aspirin (1), paracetamol (2), and caffeine (3) in saliva, after ultrasound-assisted emulsification microextraction, with chloroform on silica gel with ethyl acetate - acetic acid 19:1. Detection under UV light at 254 nm. Quantitative determination using ImageJ software. The hRF values for (1) to (3) were 90, 80 and 50, respectively. Linearity ranged between 4 and 200 μg/zone for (1) to (3). LOD and LOQ were 12 and 38 μg/zone for (1), 8 and 26 μg/zone for (2), and 7 and 23 μg/zone for (3), respectively. The intermediate precision was <10 % (n=3). Recovery was in the range of 89-94 % in saliva for (1) to (3).

Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 67, (1984). OPLC (OPTLC) of amino acids on silica with 1) butanol - acetic acid - water 4:1:1, 2) phenol -1 % SDS - isobutanol - propanol - butanol - acetic acid 70:28:2:2:2:1.7. Detection with ninhydrin + Cu or Cd acetate reagent. Detection with videodensitometer, coefficient of variation 6 %.