CBS 116, 11-12 (2016). HPTLC of lactose in milk, yoghurt, and instant sauce on silica gel with acetonitrile – water 3:1 (with 0.1 % trifluoroacetic acid) to the migration distance of 5 cm. Detection by spraying with aniline-diphenylamine-phosphoric acid reagent (2 g diphenylamine and 2 mL aniline in 80 mL methanol, 10 mL of o-phosphoric aicd 85 %, filled up to 100 mL) and heating for 10 min at 120 °C. Evaluation under white light. Elution of zones from the underivatized plate into ESI-MS with acetonitrile – water 19:1 (with 0.1 % formic acid) and detection in positive ionization mode. The method is suitable for semiquantitative determination of lactose by image evaluation and allows for confirmation of lactose-free products as such.

J. Planar Chromatogr. 29, 229-231 (2016). HPTLC of imipenem, meropenem, doripenem and eratapenem on silica gel G with 11 developing systems. Detection by spraying with iodine solution (0.2 g of potassium iodine and 0.4 g of iodine_x000D_ mixed in 20 mL of ethanol and 5 mL of hydrochloric acid), ninhydrin reagent (0.1 % ninhydrin in ethanol) or potassium permanganate solution (1 mg dissolved in 10 mL of water). The hRF values for the studied carbapenems in each developing system ranged between 13 and 58.

J. Planar Chromatogr. 29, 190-194 (2016). HPTLC of ranolazine in tablet formulations on silica gel with butanol – acetic acid – water 3:1:1. Quantitative determination by absorbance measurement at 270 nm. The hRF value of ranolazine was 56. Linearity was in the range of 100-400 ng/zone. Intermediate precisions were below 1.4 %. The LOD and LOQ were 15 and 50 ng/zone. Recoveries were between 98.2 and 101.1 %.

J. Chromatogr. Sci. 54 (1), 64-69 (2016). Micro-TLC of 11 species of the Mentha genus and two finished pharmaceutical products in two-dimensional mode in normal (NP) and reversed-phase (RP) systems on cyano phase with non-aqueous eluents for NP-TLC and with mixtures of acetonitrile with water or methanol with water for RP-TLC. Optimization of one-dimensional systems was performed by determining RM values vs. composition of mobile phase dependencies for standards occurring in various Mentha sp. On the basis of these dependencies the most selective chromatographic systems for each run were chosen. Then most selective eluents were applied to optimize two-dimensional systems by creating Rf in NP systems vs. Rf in RP systems correlations. The best two-dimensional systems were chosen on the basis of R(2) values for Rf vs. Rf correlations (the lowest values of R(2) coefficients). Two-dimensional micro-TLC was used to separate phenolic compounds of the examined plant materials.

Food Chem. 221, 535-540 (2017). HPTLC of L-hyoscyamine (1), scopolamine (2), alpha-solanine (3), and alpha-chaconine (4) in goji berries (Lycium barbarum) on silica gel with chloroform – methanol – acetone – 25 % ammonium hydroxide 375:75:50:8 for (1) and (2) and chloroform – methanol – water – 25 % ammonium hydroxide 35:15:2:1 for (3) and (4). Detection by spraying 3 times with Dragendorff reagent for (1) and (2) or Carr-Price reagent for (3) and (4), followed by heating at 105 °C after each subsequent application of the reagent. Quantitative determination by absorbance measurement at 520 nm for (1) and (2) and under white light for (3) and (4). The hRF values for (1) to (4) were 26, 71, 19 and 22, respectively. Linearities were between 900-2100 ng/zone for (1) and (2) and 900-2500 ng/zone for (3). The intermediate precisions were 6.7 % and 5.8 % (n=6) for (1) and (2), respectively and 2.6 % (n=3) for (3). The LODs and LOQs were 300 and 800 ng/zone for (1) and (2) and 196 and 588 ng/zone for (3), respectively. Recoveries ranged 81.6-98.9 % for (1) to (3).

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. Ethnopharmacol. 204, 26-35 (2017). HPTLC of quercitrin (1), isoquercitrin (2), quercitrin-3-O-β-D-xylopyranosyl-α-L-rhamnopyranoside (3) on silica gel with ethyl acetate – formic acid – acetic acid – water 100:11:11:26. Detection by spraying with NEU`s reagent (diphenylborinic acid 2-aminoethylester, natural product reagent), followed by drying at 110 °C for 2 min. Quantitative determination by absorbance measurement at 265 nm. LOD and LOQ were 31 ng/zone and 75 ng/zone for (2). Recovery was between 99.8 and 101.1 % for (2). Intermediate precision was <2 % (n=3).

J. Liq. Chromatogr. Relat. Technol. 40, 252-258 (2017). HPTLC of allocryptopine, berberine, boldine, chelidonine, papaverine, and emetine on cyano phase in different eluent systems. 2D-TLC of the same alkaloid standards on cyano phase in the first dimension with either A) methanol – diisopropyl ether – ammonia 15:83:2 or B) methanol containing 2 % acetic acid, and in the second dimension with either C) acetonitrile – water – formic acid – 1-butyl-3-methylimidazolium tetrafluoroborate 40:58.8:1:0.3 or D) acetonitrile – acetate buffer pH 3.5 – 1-butyl-3-methylimidazolium tetrafluoroborate 40:20:0.25. The best separation of the alkaloids was obtained with mobile phase C).