Anal. Bioanal. Chem. 412, 4527-4536 (2020). HPTLC of 20 chemicals representative of migrants from plastic food contact materials on silica gel with chloroform - acetone - petroleum ether 11:5:5. Yeast estrogen screen was performed by spraying with yeast culture, followed by incubation at 30 ºC for 3 h. Detection by spraying with the indicator (2 mL 0.5 mg/mL 4-methylumbelliferyl-β-D-galactopyranoside-MUG in lacZ buffer), followed by incubation at 37 ºC for 20 min. Qualitative identification under UV light at 366 and 550 nm. The method was more sensitive than a microtiter plate YES (lyticase-YES). 

Chem. Asian J. 15(19), 3044-3049 (2020). The studied rotaxane combines a dibenzocrown of 8 ethers (DB24C8) with an axle chain (Ax) containing two amines, one of them in an aniline group, allowing stability of the rotaxane even when the other one is unprotonated. TLC on silica gel in 4 steps, with detection under UV light or after derivatization with phosphomolybdic acid in ethanol. (1) Before the synthesis of the rotaxane, unprotonated Ax was isolated by preparative TLC of the protonated Ax obtained by addition of HCl or toluenesulfonic acid (TsOH); the mobile phases were chloroform – methanol 10:1 and toluene – tetrahydrofurane 3:2, respectively. The isolated molecules were confirmed as totally unprotonated Ax by NMR, suggesting a complete loss of HCl and TsOH on the silica gel layer. (2) After synthesis, unprotonated rotaxane, pure vs. monoprotonated by the addition of 10 different acids (and purified by column chromatography CC), was applied on TLC plates and developed with dichloromethane – acetone – water 3:16:1; the hRF values were very different, depending on the counter-anions from the used acids. (3) The same behavior (except with sulfuric acid) was observed under the same conditions when CC was omitted (unprotonated rotaxane samples were mixed with each of the acids, or with two acids at the same time for acid-competitive TLC analysis). (4) When unprotonated rotaxane was applied under the same conditions as in step (3) with the sodium salts instead of the acids, the behavior was similar (except for the shapes of the spots, due to the salts in excess). The rotaxane can thus be used for the TLC separation and detection of sodium salts, by forming salts of protonated rotaxane with the anion afforded by these sodium salts. The rotaxane protonation seems to be promoted by the methanol of the spotting mixture; indeed, when step (3) was performed with the mobile phase chloroform – methanol 10:1, a second zone appeared because methanol formed a salt with the rotaxane (identified by NMR).

J. of Chromatogr. A 1568, 188-196 (2018). Mass spectra by DART-MS were recorded directly in situ the bioautogram, immediately after direct bioautography (DB). This allowed to detect bioactive analytes within the bioautogram and discriminate microorganism cells and polar bioassay medium ingredients which could otherwise stress the MS system. DB-DART-MS was used for bioactive compounds in cosmetics using the Bacillus subtilis and Aliivibrio fischeri bioassays for detection of Gram-positive and Gram-negative antimicrobials. Planar yeast estrogen screen was used for detection of estrogen-effective compounds. HPTLC-DART-MS of parabens in hand creams either on silica gel with petroleum ether - glacial acetic acid 20:3 or on RP-18W with methanol - water 1:1. Detection under UV 254 and 366 nm. Bioassay by immersing the neutralized chromatograms into the bacterial suspensions.

Anal. Chim. Acta 159, 359-363 (1984). TLC of pyrene on silica with ether - 3-methylpentane 4:3. Detection by site-selection spectroscopy with excitation at 363.8 nm.

Anal. Sci. 3, 89-90 (1987). Two-dimensional TLC on silica (1st direction) and 26% acetylated cellulose (2nd direction) with solvent systems reported earlier. Quantification by synchronous fluorometry. Comparison of the results with those using conventional methods.

J. Planar Chromatogr. 3, 433-434 (1990). TLC of benzo(a)pyrene and benzo(e)pyrene on Kieselguhr impregnated with paraffin in benzene (10, 15, 20, and 25%) with methanol - water 8:2, 9:1, 10:0. Detection under UV 365 nm.

J. Chromatogr. A 710, 117-128 (1995). A review with 61 references including PC and TLC methods. Discussion of the advantages of each.

J. Liqu. Chromatogr. 23, 579-586 (2000). HPTLC of benzo[a]pyrene on hydrocarbon impregnated RP-18 plates with methanol - acetonitrile 1:1. Quantification by densitometry at 370 nm.