Chin J Anal Sci 38 (4), 433-440 (2022). TLC of acetochlor, alachlor, metolachlor, butachlor and pretilachlor in the root vegetables onion and garlic on silica gel with hexane – acetone 4:1. Detection by spraying with 5 % iodized bismuth potassium in acidic aqueous solution. Then QuEChERS (quick, easy, cheap, effective, rugged, safe)-GC-MS/MS method in the selected ion monitoring mode for determination of residues of these compounds after extraction with acetonitrile and acetonitrile - acetic acid and purification by PSA , MWCNTs , GCB and C18 at optimized conditions. The linearity ranged from 0.02 to 2.0 μg/mL for the 5 compounds with the correlation coefficients greater than 0.99, the LOQ was 0.025 mg/ kg, the average recoveries ranged from 72.0 % to 102 % with the relative standard deviations from 0.5 % to 7.9 %.

J Chromatogr Sci, 61 (3), 269-278 (2023). Development of a method for identification, quantification and stability study of linalool in Homalomena aromatica Schott, a herb with anti-rheumatism, nourishing and strengthening effects, and for the treatment of stomach disease. HPTLC hyphenated with MS for linalool on silica gel with toluene - ethyl acetate 19:1. Detection  with p-anisaldehyde reagent. The hRf of linalool is 35, identification of linalool at m/z 137, (M + H)+ by using MS technique. Study of the stability of linalool by investigating the effect of acid, base, UV, sunlight, thermal stress and H2O2 on it, the highest effect was observed with acidic pH with a 65 % degradation. The content of linalool was 58 % in the volatile oil of H. aromatica.

J  Chromatogr Sci, 61(3), 225-233 (2023). Development of a method for analyzing rosmarinic acid (RA), caffeic acid (CA), ursolic acid (UA) and oleanolic acid (OA) in different organs of Salvia deserta Schang qualitatively and quantitatively by HPTLC (A) for RA and CA, on silica gel with chloroform – methanol - formic acid 20:4:1, quantitative absorption measurement at 330 nm; (B) for UA and OA, on silica gel F254 with cyclohexane - ethyl acetate - methanol 20:4:1, quantitative absorption measurement at 550 nm. The linearity ranges were 0.13-0.44, 0.01-0.09, 0.50-2.50 and 0.50-2.50 mg for RA, CA, UA and OA, respectively, with corresponding correlation coefficients of 0.9938, 0.9981, 0.9971 and 0.9969, respectively. The recovery rates were between 95 % and 105 %. LOD and LOQ were 50, 58, 25, 33 and 160, 191, 80, 106 ng for RA, CA, UA and OA, respectively.

J Chromatogr Sci, 61 (1), 66-73 (2023). Development of a rapid, easy and simple method for the isolation and purification of α-glucosidase inhibitors of the ethyl acetate extract of Thymelaea hirsuta (EaTh) by TLC-enzymatic test (TLC/EZ), after EaTh demonstrated previously a potent α-glucosidase inhibitory effect. Soxhlet extraction from Thymelaea hirsuta (T. hirsuta), separation on a silica gel column, TLC on silica gel. Detection of α-glucosidase inhibitors directly on the TLC plate using the glucose oxidase peroxidase method (GOD-POD), then characterization of active compounds using HPLC-MS analysis, resulting the main α-glucosidase inhibitors present in EaTh with a molecular ion [M + H]+ at m/z = 543. The proposed method is suitable for a reliable isolation and purification of α-glucosidase inhibitors present in EaTh and can be proposed as an interesting alternative to the classical method for the isolation and purification of α-glucosidase inhibitors in plant extracts.

J. Chromatogr. Sci., 61 (1), 56-65 (2023). Proposal of a method for the simultaneous determination of acefylline piperazine (ACEF) and phenobarbital (PHENO) in presence of methylparaben as additive in pharmaceutical dosage form by TLC on silica gel with chloroform – methanol - glacial acetic acid 20:80:1. Densitometric absorption measurement at 254 nm in the concentration range of 0.5 - 25 μg/band. Also, reversed phase liquid chromatography (RPLC) with diode array detection. Validation of both methods according to the International Conference on Harmonization guidelines and statistical comparison with a reported HPLC method. Successful application of the proposed planar chromatographic method firstly for the determination of ACEF and PHENO in pharmaceutical dosage form.

J. Chinese Trad. Patent Med. 44 (6), 1770-1772 (2022). Ganqingqinglan (Dracocephalum tanguticum Maxim.) is a traditional Tibetan medicinal plant, containing flavonoids, terpenes, polysaccharides. It has antihypoxic, antibacterial, antiviral, and hypoglycemic effects and is used as the main component in the traditional Tibetan medicine for the treatment of hepatitis and gastritis. For quality control, TLC of the plant extracts on silica gel (1) for oleanic acid, with toluene - ethyl acetate - glacial acetic acid 28:8:1, detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 °C until the zones are clearly visualized, evaluation under UV 366 nm; (2) for chlorogenic acid, with toluene - methyl acetate - propanone - methanol - methyl acid 30:5:5:20:1, evaluation under UV 366 nm. The method was applied for the analysis of 18 batches of real life samples and proved to be simple, specific, reproducible, robust and well suitable for the purpose.

J. Planar Chromatogr. 36, 21-30 (2023). HPTLC of tinidazole (1) and ciprofloxacin (2) in pure form, tablet dosage form and human plasma on silica gel with acetone - ethanol - 2 % watery sodium dodecyl sulfate 3:4:2. Quantitative determination by absorbance measurement at 310 nm. The hRF values for (1) and (2) were 22 and 42, respectively. Linearity was in the range of 25-1000 ng/zone for (1) and 80-1000 ng/zone for (2). Intermediate precisions were below 2 % (n=3). LOD and LOQ were 7 and 20 ng/zone for (1) and 25 and 75 ng/zone for (2). Average recovery was 99.9 % for (1) and 99.7 % for (2).

J. Sep. Sci. 2300332 (2023). HPTLC of cilnidipine on silica gel with n-heptane - ethyl acetate - triethyl amine 6:14:1. Quantitative determination by absorbance measurement at 254 nm. The hRF value for cilnidipine was 42. Linearity was in the range of 100-500 ng/zone. Intermediate precisions were below 2 % (n=3). LOD and LOQ were 24 and 72 ng/zone, respectively. Recovery was between 98 and 102 %.