J Am Soc Mass Spectrom 31(9), 1981-1993 (2020). Low-temperature plasma-mass spectrometry was studied for comparison between direct desorption (DD) and diode laser assisted desorption (LD) in terms of quantitative and qualitative analysis of compounds from cellulose vs. silica gel TLC layers. Compounds (the 20 common amino acids, propofol, nicotine, cotinine, salicylamide, acetylsalicylic acid, paracetamol, caffeine, valprolactone and its isomer 4-ene-valproic acid) were applied on the TLC plates (without development) at different concentrations; a commercial mixture of acetylsalicylic acid, paracetamol and caffeine was also applied on TLC plates, developed with dichloromethane – ethyl acetate 1:50, detection at UV 254 nm and quantitative MS. In general, DD provided good results on cellulose, where LODs where between 0.01 and 2.55 ng/mm2, whereas several compounds remained undetected on silica gel. LD however provided LODs on silica gel from 0.3 to 84 pg/mm2. Tandem MS with collision-induced dissociation was implemented to improve signals, LODs and to characterize the other analytical figures-of-merits (including detection of the main fragment ions, determination of optimal laser beam width and irradiance depending on the compounds). For the two metabolites of valproic acid, the ions and fragments had identical values; therefore, a mix of the two isomers had to be applied and separated with dichloromethane – methanol 50:1 before MS; one half of the plate was visualized for control by dipping into potassium permanganate reagent (7.5g KMnO4, 50g K2CO3, 0.75g NaOH in 1L water).

Planta Med. 84(18), 1348-1354 (2018). A subfraction (obtained through liquid-liquid partition and column chromatography) of the ethanolic extract of whole Vernonia cinerea plants (Asteraceae, subf. Cichorioideae) was further fractioned by reverse-phase SPE (solid-phase extraction) followed by preparative TLC on silica gel layer (eluent not given). For verification, zones were detected by spraying with anisaldehyde solution with 10 % sulfuric acid, followed by heating at 100 °C. Further purification by reverse-phase HPLC allowed the isolation of 6 hirsutinolide-type sesquiterpenoids (all with a oxacyclonane forming an ether bridge), including vernolides A and B.

Planta Med. 84(16), 1174-1182 (2018). The fractionation and purification steps (column chromatography, including reverse-phase HPLC) of an ethanolic extract of Millettia pinnata (= Pongomia pinnata, Fabaceae) roots were monitored by TLC on silica gel with n-hexane – ethyl acetate mixtures 4:1 - 2:1. Detection at 254 and 336 nm, and by spraying with sulfuric vanillin reagent followed by heating. The process allowed the isolation of 2 flavanols (including pongaflavanol), 1 flavanol ether and 26 flavanones (including derrivanone, griffinones, isoderricines, isoglabrachromene, isolonchocarpin, liquiritigenin, maxima flavanone A, ovalichromene B, ovaliflavanones, pinostrobin, pongachin, pongamone C, ponganone III).

Planta Med. 84(12-13), 941-946 (2018). The activity-guided fractionation and purification steps (column chromatography and liquid-liquid partitions) of a hydromethanolic extract of Alchemilla vulgaris aerial parts (Rosaceae) were monitored by TLC on silica gel with ethyl acetate – acetic acid – formic acid – water 100:11:11:27. Detection at 254 and 336 nm, and by spraying with anisaldehyde reagent followed by heating. A flavonoid (quercetin-glucuronide) was isolated through this process.

Planta Medica 84(12-13), 902-912 (2018). A dichloromethane extract of Athrixia phyllicoides aerial parts (Asteraceae) was eluted on a silica gel column with different mixtures of ethyl acetate and hexane or methanol. This fractionation was monitored on TLC silica gel layers, using the combinations of the same solvents as mobile phases. Detection by derivatization with Natural Product Reagent and PEG, and visualization at UV 254 nm. This allowed the grouping of the fractions into 13 profiles and the isolation of three hydroxy-methoxyflavones and a coumarate.

Planta Medica 84(9/10), 710-715 (2018). The fractionation of an n-butanol extract of Cistanche phelypaea (Orobanchaceae) aerial parts through cyclodextran column chromatography with methanol was monitored on TLC silica gel with chloroform – methanol – water 70:30:3, detection by spraying with cerium sulfate reagent. In the 11 major fractions obtained, 4 new phenylethanoid glycosides were further identified, as well as brandioside (a phenylpropanoid glycoside), and heterosides of apigenin (flavonoid) and of pinoresinol (lignan).

Planta Medica 84(9/10), 716-720 (2018). The fractionations of n-hexane and chloroform extracts of Guarea guidonia aerial parts (Meliaceae) through silica gel column chromatography was monitored on TLC silica gel with cerium sulfate / sulfuric acid as derivatization reagent. In the fractions obtained, 3 new tirucallane-type triterpenoids (guareolide, guareoic acids A and B) were further identified, as well as other terpenoids (flindissone, acetyldihydronomilin, picroquassin E, boscartol C, and acneorubins A, B, and X).

Planta Medica 84(9/10), 729-735 (2018). The chloroform fraction of a methanolic extract of Euphorbia taurinensis whole plant (Euphorbiaceae) was submitted to a multi-step fractionation through column chromatography. Monitoring by TLC on silica gel (mobile phases see below) followed by derivatization with concentrated sulfuric acid and heating at 105°C. The fractions obtained were purified by repeated cycles of preparative TLC alone or alternating with preparative HPLC, leading to the isolation of segetane, ingenane, and jatrophane diterpenes. Depending on the subfractions, preparative TLC silica gel and reverse-phase C18 layers were used, with cyclohexane – ethyl acetate – ethanol 25:15:1 for normal phase, and with mixtures of acetonitrile (or methanol) and water for RP.