Journal of Chromatography B, 1184, 122956 (2021). Test for acetyl- and butyrylcholinesterase (AChE and BChE) inhibition without development of piperin (standard inhibitor of AChE and BChE) and ethanol – water (3:2) extracts of Iranian plants, on HPTLC silica gel prewashed twice with methanol – water 3:2 and dried 60 min at 120°C. After sample application the plate was immersed (speed 3.5 cm/s, time 2 s) into enzyme solution (6.6 units/mL AChE or 3.3 units/mL BChE in TRIS buffer 0.05 M, with bovine serum albumin 0.1 %, pH 7.8), incubation 25 min at 37°C and immersion (speed 3.5 cm/s, time 1 s) into chromogenic substrate solution (α-naphthyl acetate 0.1 % and Fast Blue salt B 0.2 % in ethanol – water, 1:2). Seven mobile phases were tested for the active samples. Best separation was obtained with toluene – ethyl acetate – formic acid – water 4:16:3:2 and with toluene – ethyl acetate – methanol 6:3:1. Before enzymatic assay, plates developed with acidic mobile phases were neutralized by spraying 3 mL citrate phosphate buffer (Na2HPO4 8 %, citric acid q.s. ad pH 7.5) followed by 10 min of automatic drying. Enzymatic assay was performed using a piezoelectric spraying device: a) pre-wetting by spraying 1 mL TRIS buffer (0.05 M, pH 7.8); b) spraying 3 mL of the enzyme solution; c) incubation 25 min in a humid box at 37°C; d) spraying 0.5 mL substrate solution; e) 5 min drying at room temperature, and then 10 min of automatic drying. By spraying, zone shift and zone diffusion, which occurred with plate immersion, were avoided. For development control, derivatization was done by piezoelectrically spraying 4 mL of sulfuric anisaldehyde reagent (anisaldehyde – sulfuric acid – acetic acid – methanol, 1:10:20:170), followed by heating 3 min at 110°C. For identification of zones of interest, direct elution with methanol from underivatized HPTLC plates through a TLC-MS interface directly to a MS. Identified zones were 3-O-acetyl-β-boswellic acid (triterpenoid) from Boswellia carteri gum-resin (Burseraceae), pimpinellin and psoralen (furocoumarins) from Heracleum persicum flowers (Apiaceae), oleuropein (seco-iridoid) from Olea europaea leaves (Oleaceae), harmine, harmaline, vasicine, deoxyvasine (alkaloids) from Peganum harmala seeds (Zygophyllaceae), costic acid (sesquiterpene) from Nardostachys jatamansi hypocotyl (Valerianaceae), elaidic, linoleic, palmitic, palmitoleic acids (fatty acids) from Pistacia atlantica fruits (Anacardiaceae).

J. Planar Chromatogr. 34, 455-466 (2021). HPTLC of mometasone furoate (1) and salicylic acid (2) on silica gel with chloroform - ethanol 9:1. Quantitative determination by absorbance measurement at 250 nm for (1) and 300 nm for (2). The hRF values for (1) and (2) were 13 and 93, respectively. Linearity was between 100 and 1600 ng/zone for (1) and 400 and 5000 ng/zone for (2). LOD and LOQ were 16 and 47 ng/zone for (1) and 7 and 20 ng/zone for (2), respectively. Intermediate precisions were below 2 %. Recovery was between 98 and 102 %.

J. Planar Chromatogr. 34, 411-418 (2021). HPTLC of sphingomyelin in erythrocyte membranes of patients on silica gel with chloroform - methanol - acetic acid - water 60:50:1:4. Detection by exposure to iodine vapor for 30 min. Quantitative determination by densitometric measurement of the intensity of individual zones and the red, green and blue values of the component colors. The hRF value for sphingomyelin was 86. Linearity was between 0.25 and 10 μg/zone. LOD and LOQ were 140 and 410 ng/zone, respectively. Intermediate precisions were below 2 % (n=3). Recovery was between 85 and 97 %.

J. Planar Chromatogr. 34, 427-435 (2021). HPTLC of phyllanthin (1) and hypophyllanthin (2) in Phyllanthus amarus on silica gel with toluene - ethyl acetate 17:3. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) and (2) were 21 and 35, respectively. Linearity was between 2 ans 7 μg/zone for (1) and (2). LOD and LOQ were 1 and 3 μg/zone for (1) and (2), respectively. Intermediate precisions were below 2 % (n=3).

J. Planar Chromatogr. 34, 467-477 (2021). HPTLC of five antihypertensive drugs, atenolol (1), amlodipine (2), losartan (3), hydrochlorothiazide (4), and telmisartan (5) on silica gel with chloroform - toluene - methanol - acetone - formic acid 400:300:150:260:3. Quantitative determination by absorbance measurement at 254 nm. The hRF values for (1) to (5) were 7, 12, 45, 56 and 64, respectively. Linearity ranged from 1-25 μg/zone for (1), (3) and (5) and 1-20 μg/zone for (2) and (4). LOD and LOQ were 300 and 900 ng/zone for (1), 130 and 420 ng/zone for (2), 230 and 690 ng/zone for (3), 140 and 430 ng/zone for (4) and 190 and 560 ng/zone for (5). Intermediate precisions were below 1 % (n=9). Mean recovery was 99.3 % fo (1), 100.1 % for (2), 99.7 % for (3), 99.7 % for (4) and 100.3 % for (5).

J. Planar Chromatogr. 34, 353-359 (2021). HPTLC of alkaloids in the leaves of Solanum retroflexum on silica gel with chloroform - ethyl acetate - methanol 9:8:3. Detection under UV light at 365 nm. Further analysis of extracted zones by ultra-high performance liquid chromatography-quadrupole time-of-flight hyphenated to mass spectrometry (UHPLC‒QTOF‒MS).

J. Planar Chromatogr. 34, 323-328 (2021). HPTLC of plumbagin in the roots of Plumbago zeylanica on silica gel with toluene - ethyl acetate 9:2. Quantitative determination by absorbance measurement at 270 nm. The hRF value for plumbagin was 84. Linearity was between 100 and 600 ng/zone. LOD and LOQ were 70 and 200 ng/zone, respectively. Intermediate precisions were below 2 % (n=3). Average recovery was 98.8 %.

J. Planar Chromatogr. 34, 337-343 (2021). HPTLC of montelukast (1) and bilastine (2) on silica gel with acetonitrile - ethyl acetate - ammonia 40:60:1. Quantitative determination by absorbance measurement at 282 nm. The hRF values for (1) and (2) were 53 and 27, respectively. Linearity was between 100 and 500 ng/zone for (1) and 200 and 1000 ng/zone for (2). LOD and LOQ were 13 and 40 ng/zone for (1) and 65 and 198 ng/zone for (2). Intermediate precisions were below 2 % (n=3). Recovery was between 98.0 and 99.7 % for (1) and 98.0 and 99.0 % for (2).