Trends Anal. Chem. 157, 116828 (2022). Review of the analysis of drugs of abuse in exhaled breath. The paper described sampling devices, sample pretreatment techniques and the application of chromatographic techniques, including TLC for the analysis of drugs of abuse.

J Chromatogr A, 1624, 461239 (2020). Samples were chemical standards of acetylcholinesterase (AChE) inhibitors (azamethiphos, caffeine, donepezil, galanthamine, methiocarb-sulfoxide, paraoxon-ethyl) and of neurotoxic compounds, as well as drinking or contaminated water samples enriched through solid phase extraction. HPTLC on spherical silica gel (pre-washed twice by 20 min immersion in isopropanol, heated 20 min at 120 °C before and after pre-washing with acetonitrile). First separation (preparative TLC) with automated multiple development (16 steps). Effect-directed analysis for AChE inhibitors by immersion (speed 5 cm/s, time 1 s) into enzyme solution, incubation 5 min at 37 °C and immersion into substrate solution (indoxyl acetate 2 % in methanol); visualization under UV 366 nm. Active zones from untreated layers were eluted through the oval head of a TLC-MS interface to a second plate for a second separation with a panel of other mobile phases. Bands of interest were eluted from the second layer with water through the oval elution head of the TLC-MS interface pump, into a RP18 liquid chromatography guard column, followed by a quadrupole time-of-flight mass spectrometer. Full scan mass spectra (m/z 100–1200) were recorded in negative and positive modes using electrospray ionization (and collision-induced dissociation for MS2). Among the water contaminants, lumichrome (riboflavin photolysis product), paraxanthine and linear alkylbenzene sulfonates were identified as AChE inhibitors.

J Chromatogr A, 1619, 460945 (2020). Samples were lamotrigin as standard, or extracted with an oil-in-water microemulsion (10 µL butyl acetate, 4 mL n-butanol, 925 mg sodium dodecyl sulphate, 8.6 mL water) either from patients’ raw plasma (for separation from blood proteins) after spiking, or from commercial tablets dissolved in methanol. TLC on silica gel with a water-in-oil microemulsion of 9 mL butyl acetate, 1 mL n-butanol, 250 mg sodium dodecyl sulphate, 250 µL water. Both optimal microemulsions were predicted using Taguchi orthogonal array and Plackett-Burman design. Evaluation in UV 254 nm, quantification from the digital picture using four image processing software programs. For lamotrigin (hRF 24), limits of quantification were 170 ng for pure drug and 10 ng for spiked plasma. Linearity (in range 20–200 ng/spot) was directly obtained for the calibration curve in spiked plasma; however, for pure drug, linearity was obtained only when using log values of the calculated densities (300–3000 ng/spot).

J Chromatogr A, 1684, 463582 (2022). Samples were concentrated filtrates of leachates of waste deposition sites, as well as testosterone, flutamide, bisphenol A (BPA) and nitroquinoline oxide (NQO) as standards. Automated Multiple Development on HPTLC silica gel (prewashed with methanol and dried 30 min at 110 °C) with 1) methanol up to 20 mm; 2A) chloroform – ethyl acetate –petroleum ether 11:4:5 or 2B) ethyl acetate – n-hexane 1:1 for flutamide and testosterone, up to 90 mm. Effect-directed analysis was performed by automated spraying 3 mL suspension of BJ1991 yeast (transfected Saccharomyces cerevisiae strain, pure for androgenic activity, with 50 ng/mL testosterone for anti-androgenic assay), followed by 20 h incubation at 30 °C in a closed chamber (90 % relative humidity), by 5 min drying under cold air stream, by spraying 2.5 mL MUG solution (4-methylumbelliferyl-galactopyranoside) and by 15 min incubation at 37 °C in an open chamber. Agonistic and antagonistic activities were detected qualitatively under UV 366 nm (light or dark blue bands, respectively, on blue background) and quantitatively documented using automated scanning at excitation wavelength 320 nm (deuterium lamp), with cut-off filter at 400 nm. Dose-response curves for model compounds were established by regression analysis. Anti-androgenic effective doses at 10 % were 28 ng/zone for flutamide and 20 ng/zone for BPA, without toxicity for the yeast. To exclude cytotoxicity where anti-androgenic activity was observed, the HPTLC layers (either without or after the spraying with MUG) were sprayed with 3 mL resazurin solution (0.01 % in water) and incubated 30 min at 30 °C and 90 % humidity. Cytotoxicity bands appeared as pink zones of resorufin on a colorless background (dihydroresorufin) under white light. Densitometric evaluation in absorption mode at 575 nm (under deuterium and halogen-tungsten lamps, no filter applied). NQO was cytotoxic at its lowest tested dose (1 ng/zone).

J. Planar Chromatogr. 35, 543-546 (2022). HPTLC of diazepam in spiked lemon juice drink on silica gel with chloroform - acetone 4:1 (system 1) and chloroform - methanol - ethyl acetate 14:3:1 (system 2). Detection under UV light at 254 nm. The hRF values for diazepam in systems 1 and 2 were 72 and 88, respectively. 

J. Planar Chromatogr. 35, 363-373 (2022). HPTLC of midazolam (1), prochlorperazine (2), citalopram (3) and chlorodiazepoxide (4) in urine on silica gel with cyclohexane - toluene - diethylamine 14:3:3. Quantitative determination by absorbance measurement at 229 nm for (1), 257 nm for (2), 240 nm for (3) and 275 nm for (4). The hRF values for (1) to (4) were 31, 79, 63 and 7, respectively. Linearity was between 3 and 7 µg/zone for (1) to (4). Interday and intra-day precisions were below 5 % (n=3). The LOD and LOQ were 0.5 and 1.6 µg/zone for (1), 0.7 and 2.1 µg/zone for (2), 0.5 and 1.6 µg/zone for (3) and (4).  Average recovery was 95.5 % for (1), 90.5 % for (2), 95.9 % for (3) and 92.5 % for (4).

J. Planar Chromatogr. 35, 431-434 (2022). HPTLC of carbaryl in biological material on silica gel with hexane - acetone 4:1. Detection by spraying with reagent A (4 g sodium hydroxide in 100 mL water), waiting for 10 min, followed by spraying with reagent B (2 g vanillin in 100 mL acetone). Brown-colored zone with white background was clearly visible. The hRF values for carbaryl were 22 and 54.

ALTEX - Alternatives to animal experimentation, 38(3), 387-397 (2021). Samples were standards of food contact contaminants with genotoxicity (4-nitroquinoline-1-oxide (NQO), aflatoxin B1, hexachloroethane, nitroso-ethylurea, phenformin, PhIP) or negative controls (alosetron, mannitol), and extracts of coated tin cans (extracted with n-hexane – acetone at 25°C for 16 h or by heating at 60 °C with ethanol 95 % for 240 h). HPTLC on RP18W layer, pretreated to harden the binder by heating 1 h at 120 °C, prewashed with methanol and with ethyl acetate and dried 4 min in cold air stream after each development. Application areas were focused to their upper edges by a two-fold elution with ethyl acetate, followed by 1 min drying in cold air stream. Development with toluene – ethyl acetate 8:5, followed by 5 min drying, neutralization with citrate buffer (pH 12) and 4 min drying. Effect-directed analysis for genotoxicity (SOS response – UMU-C test, using NQO as positive control) by immersion (speed 3.5 cm/s, time 3 s) into Salmonella typhimurium suspension and, after 3 h incubation at 37 °C and 4 min drying in cold air stream, into one of two fluorogenic substrate solutions (methylumbelliferyl- vs. resorufin-galactopyranoside). After 1 h incubation at 37 °C, visualization of mutagenic compounds as (blue vs. red) fluorescent zones at FLD 366 nm, and densitometry performed with mercury lamp for fluorescence (at  366 / >400nm vs. 550 / >580 nm, respectively). Further validation experiments, including spiking extracts with NQO, were performed showing good mean reproducibility, no quenching or other matrix effects. Lowest effective concentration of NQO was 0.53 nM (20 pg/band), 176 times lower than in the corresponding microtiter plate assays.