Braz. J. Pharm. Sci. 49, 845-851 (2013). HPTLC of metoprolol (1) and hydrochlorothiazide (2) in human plasma on silica gel with chloroform - methanol - ammonia 18:2:1. Quantitative determination by absorbance measurement at 239 nm. The hRF values for (1) and (2) were 48 and 13. Linearity was in the range of 20-120 μg/zone for (1) and 2-12 μg/zone for (2). The intermediate/interday/intra-day precisions were below 5 % (n=3). The LOQs were 20 and 2 μg/zone for (1) and (2), respectively. Recoveries were between 70.6 and 84.9 %.

J. Liq. Chromatogr. Relat. Technol. 38, 1279-1285 (2015). TLC of Citrus herbal medicines on NaOH-modified silica gel with ethyl acetate - methanol - water 100:17:13, followed by drying at room temperature and second development with toluene - ethyl acetate - formic acid - water 20:10:1:1. Detection by spraying with 1 % aluminium chloride ethanolic solution. The greyscale image captured under UV 365 nm was corrected by removing the quadratic baseline trend of the densitometric curve of every row.

J. Chromatogr. Sci. 54 (1), 70-78 (2016). HPTLC of flurbiprofen and chloramphenicol in the presence of their degradation products, produced in acidic, alkaline, neutral, oxidative, photolytic and thermal stress conditions, on silica gel with ethyl acetate – n-hexane – methanol – triethylamine 10:8:4:1. The hRf of flurbiprofen was 29 and of chloramphenicol 62. Quantitative determination by densitometry at 267 nm. Linearity was between 12 and 60 ng/zone with a correlation coefficient of 0.9997 for flurbiprofen and between 200 and 1000 ng/zone with a correlation coefficient of 0.9977 for chloramphenicol. The application of the method to the estimation of flurbiprofen and chloramphenicol in commercial ophthalmic formulation indicated that the method was specific, accurate, reproducible and suitable for routine analysis of flurbiprofen and chloramphenicol in the presence of their degradation products in their individual as well as combined pharmaceutical formulations.

J. Chromatogr. Sci. 55 (10), 1059-1065 (2017). Presentation of a new high-throughput method for the simultaneous analysis of isoflavones and soyasaponins in soy (Glycine max L.) products by HPTLC on silica gel with ethyl acetate – methanol – water – acetic acid 100:20:16:1. Detection by treatment with anisaldehyde sulfuric acid reagent. Quantitative determination by densitometric multi-wavelength scanning at UV 265 nm for genistin, daidzin and glycitin and at 650 nm for soyasaponins I and III. The correlation coefficient of the linear calibration curve was >0.994. Intra-day precision (%RSD) of substances in matrix was between 0.7-0.9 %, inter-day precision (%RSD) was between 1.2-1.8 %). The method was suitable for the determination of the studied analytes in soy-based infant formula and soybean products.

CBS 120, 14-15 (2018). The drugs cefixime trihydrate (CEFI) and azithromycin dihydrate (AZI) were subjected to hydrolytic degradation (with water, 0.5 N HCl or 0.5 N NaOH), oxidative degradation (with 3 % and 30 % hydrogen peroxide), thermal degradation (heated at 100 °C and 200 °C for 1 h and 2 h) and photolytic degradation (exposed to fluorescent cold white light and UV light). HPTLC of CEFI, AZI, and the degradation samples on silica gel with ethyl acetate – methanol – acetone –_x000D_ toluene – ammonia 2:10:14:1:1 to the migration distance of 80 mm. Detection of AZI by immersion into sulfuric acid reagent (1:4 in ethanol) and heating at 100 °C for 5 min. Evaluation under UV 254 nm, UV 366 nm, and white light. Quantitative determination by absorbance measurement at 235 nm for CEFI and 530 nm for AZI. Linearity was in the range of 500–2500 ng/zone for CEFI and 50–250 ng/zone for AZI. The LOD and LOQ (ng/zone) for CEFI were 58 and 175, respectively, and for AZI 3 and 10, respectively. Precision (%RSD) was <2 %. In the forced degradation studies, CEFI degraded to 4 major products under different stress conditions. AZI showed only one additional peak upon acid and neutral hydrolysis.

Proc. Intern. Symposium on TLC with special Emphasis on OPLC, Szeged, 76 (1984). OPLC (OPTLC) on silica of neutral lipids with petrol ether - ether - acetic acid 50:50:1, glycolipids with chloroform - acetone - acetic acid - water 10:90:3:2, phospholipids with methyl acetate - propanol - chloroform - methanol - 43 mmol/1 NH4Cl 25:25:25:10:9. Detection with 0.2 % K2Cr2O7 in 45 % sulfuric acid.

Prepacked-column extraction and quantitative HPTLC-determination of the aflatoxins B1, B2, G1 and G2 in fungal suspensions.) Fresenius Z. Anal. Chem. 319, 527-532 (1984). Quantitative determination of aflatoxins by HPTLC after prepacked column extraction. HPTLC on silica with chloroform - acetone 9:1 and post-chromatographic treatment with paraffin - hexane 1:2. In-situ fluorescence scanning at 344/430 nm.

Anal. Chem. 55, 2429-2431 (1982). Procedure for evaluating sensitivity of a scanning densitometer operated in the reflectance or transmission mode. Azobenzene or phenylacetylene as reference standards.