Food Chem. 351, 129211 (2021). High-throughput planar solid-phase extraction of 66 multi-class antibiotic residues in muscle tissue, cow milk and chicken eggs on silica gel with acetonitrile - methanol - ammonia 5:3:2 as first front-elution up to 85 mm followed by a second front-elution in the reverse direction up to 25 mm with acetonitrile -water - ammonia 9:7:4. Evaluation under UV 254 nm and 366 nm. Detection of macrolides by spraying with p-anisaldehyde sulfuric acid reagent (methanol - glacial acetic acid - sulfuric acid - p–anisaldehyde 420:50:26:3), followed by heating at 110°C for 3 min. Detection of penicillins by spraying with ninhydrin reagent (500 mg ninhydrin in ethanol - glacial acetic acid 23:2). Detection of lincosamines by spraying with aniline diphenylamine o-phosphoric acid reagent (2 g diphenylamine in methanol – o-phosphoric acid - aniline 90:10:1). Via simple clicks on the image, the auto TLC-MS interface automatically eluted the target zones at the trace level from the TLC plate into a Q Exactive Plus Hybrid Quadrupole-Orbitrap Mass Spectrometer.

J. Liq. Chromatogr. Relat. Technol. https://doi.org/10.1080/10826076.2021.1968429 (2021). Review of bioautography procedures of antimicrobial compounds in plants, including extraction of plant material, stationary and mobile phases in direct bioautography, chemical derivatization and biological detection of bioactive compounds and structure elucidation of bioactive bands. The paper also discussed new aspects of identification of biologically active substances in accordance with the principles of green analytical chemistry, and with special reference to substances with antimicrobial properties.

J. Liq. Chromatogr. Relat. Technol. https://doi.org/10.1080/10826076.2021.1930555 (2021). HPTLC of ofloxacin (1), tinidazole (2), terbinafine hydrochloride (3), and clobetasol propionate (4) on silica gel with toluene - ethyl acetate - methanol - triethylamine - formic acid 50:40:10:3:3. Quantitative determination by absorbance measurement at 238 nm. Linearity was between 300 and 1500 ng/zone for (1) to (4). The intermediate precision was below 2 % (n=6). Recovery was between 98.9 and 99.1 % for (1), 98.9 and 99.3 % for (2), 99.0 and 99.5 % for (3) and 98.9 and 99.3 % for (4).

J. AOAC Int. 103, 980-988 (2020). HPTLC of imidocarb dipropionate and its forced induced degradation products in bovine meat and milk on silica gel with ethyl acetate - methanol - ammonia - water 85:10:5:2. Quantitative determination by absorbance measurement at 254 nm. Linearity was between 100 and 1800 ng/zone. Intermediate precision was below 1 % (n=3). The LOD and LOQ were 17 and 52 ng/zone, respectively. Average recovery was 100.8 %. The HPTLC method showed comparable results to a validated HPLC method for resolution and determination of imidocarb in the presence of its degradation products.

J. Planar Chromatogr. 34, 121-129 (2021). HPTLC of cefoperazone (1) and sulbactam (2) on silica gel with acetone - ethanol - ethyl acetate - 2 % sodium dodecyl sulfate - glacial acetic acid 6:4:8:2:1. Quantitative determination by absorbance measurement at 265 nm. The hRF values for (1) and (2) were 45 and 69, respectively. Linearity was between 150 and 1000 ng/zone for (1) and 100 and 1000 ng/zone for (2). Intermediate precision was below 2 % (n=3). The LOD and LOQ were 42 and 129 ng/zone for (1) and 30 and 90 ng/zone for (2), respectively. Recovery was between 99.5 and 100.5 % for (1) and 99.1 and 100.4 % for (2).

Food Addit. Contam. Part A. 36, 1218-1227 (2019). Preparative TLC of florfenicol and florfenicol amine in porcine urine on silica gel with dichloromethane - acetone - ammonium hydroxide 20:20:1. Qualitative identification under UV light at 254 nm. Zones were scraped off and extracted for HPLC analysis.

J. Chromatogr. B 877 (29), 3719-3723 (2009). HPTLC of gemifloxacin mesylate in human plasma, extracted with chloroform - acetic acid 59:1, on silica gel with ethyl acetate – methanol - ammonia 8:4:3. The hRf value of gemifloxacin mesylate was 33. Quantification by densitometry at 254 nm. The calibration curve was established in the range of 50 to 600 ng/spot. Recovery of gemifloxacin mesylate was between 80.0 and 86.2 %. The stability of gemifloxacin mesylate in plasma was confirmed with samples submitted to three cycles of freeze–thawing at -20 °C, and with samples stored on the bench for 12 h.

J. Planar Chromatogr. 24, 520-523 (2011). HPTLC of streptomycin and amoxicillin, ampicillin, cefixime, cephalexin, cloxacillin, co-trimoxazole, doxycycline, erythromycin, gentamycin, metronidazole, tetracycline on titanium(IV) silicate coated plates with 0.5 M potassium bromide and ethanol 9:1 in a twin-trough chamber. Detection by spraying with a fresh 2 % solution of sodium carbonate and 5 % sodium nitroprusside dihydrate in 1 % acetaldehyde 1:1 or iodine solution (2 g iodine and 3 g potassium iodide in 100 mL water). Quantitative determination by densitometry in absorbance mode at 359 nm. The recovery was 97.9 %. LOD and LOQ were 2 and 12 ng/zone, respectively.