J Chromatogr A, 1602, 458–466 (2019). HPTLC of caffeine, physostigmine (alkaloids) and hydroethanolic extract of Peganum harmala seeds (Nitrariaceae, Zygophyllaceae) on silica gel prewashed twice with methanol – water 3:1, followed by 1 h drying at 120 °C. Separation, after 5 min chamber saturation, with ethyl acetate – methanol – ammonia (25%) 85:11:4 (basic mobile phase) or ethyl acetate – toluene – formic acid – water 16:4:3:2 (acidic mobile phase, requiring neutralization with phosphate-citrate buffer). Derivatization with Dragendorff’s reagent and with anisaldehyde sulfuric acid. Effect-directed analysis by spraying A) with Gram-negative bioluminescent Aliivibrio fischeri suspension for antibacterial activity (caffeine was used as standard); B) with acetyl- and butyryl-cholinesterase (AChE / BChE) solutions for enzymatic inhibition. For AChE and BChE asssays, classical immersion into the enzyme solutions was also used for comparison, and inhibition densitometry for active analytes was performed by inverse scan measurement (fluorescence without optical filter) at 546 nm using a mercury lamp; activity was expressed as physostigmine equivalents. Active bands were eluted (only after basic MP) with methanol through the oval elution head of a TLC-MS interface pump, into a quadrupole-Orbitrap mass spectrometer. Full scan mass spectra (m/z 50−750) in positive ionization mode were recorded using heated electrospray ionization (HESI, spray voltage 3.5kV, capillary temperature 270°C). By comparison to literature, AChE inhibitors (also active against A. fischeri) were assigned to be harmine, harmaline and ruine (β-carboline alkaloids), and BChE inhibitors were harmol (same class) and vasicine and deoxyvasicine (quinazoline alkaloids, also called peganine and deoxypeganine). Piezoelectric spraying had the following advantages over automated immersion: (1) it covered the whole plate surface; (2) required much lower volumes of solutions; (3) applied always fresh enzyme or reagent solutions, thus avoiding gradual inactivation; (4) avoided zone distortions, shifts or tailings occurring during immersion or withdrawal of the plate, or due to the hydrophilicity of compounds.

J. Planar Chromatogr. 32, 55-57 (2019). TLC of dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, diallyl phthalate, and bis(2-ethylhexyl) phthalate on silica gel with petroleum ether - ethyl acetate - phosphoric acid 9:1:1. Detection by spraying with 0.1 % 2,6-dichlorophenolindophenol with the instantaneous appearance of pink-colored zones.

J. Planar Chromatogr. 21, 221-223 (2008). Construction of a simple and inexpensive compressed air-driven spraying device which can handle small and large volumes of TLC derivatization reagents. The device is made from widely available HPLC accessories, including stainless-steel fittings and tubing, and can be used with corrosive liquids with a wide range of viscosity. TLC of fluorescein, methyl red, bromocresol green, phenolphthalein, and crystal violet on RP-18 with methanol - water 7:3. Evaluation under white light.

J. Liq. Chromatogr. Relat. Technol. 38, 1104-1108 (2015). HPTLC of trans-resveratrol on silica gel with ethyl acetate - cyclohexane - n-butanol 9:9:2. Detection through chemiluminescence by dipping into a TCPO solution (250 mg bis(2,4,6-trichlorophenyl)oxalate in 36 mL n-butyl acetate, followed by adding 0.4 mL hydrogen peroxide that was vigorously shaken with the solution for 20 min). The HPTLC plate was covered by a glass plate and measured for 2 min using a very light-sensitive CCD camera. The hRF value for trans-resveratrol was 78. Linearity was in the range of 20-500 ng/zone. LOD and LOQ were 13.7 and 20.3 ng/zone, respectively.

J. Chromatogr. 350, 468-470 (1985). TLC of various steroids on silica with chloroform - methanol 10:1. Detection by spraying with 1 % rubeanic acid in concentrated sulfuric acid. Evaluation by densitometry. Detection limits 0.1-0.3 mg for most steroids examined.

J. Planar Chromatogr. 2, 65-70 (1989). For qualitative analysis monodansyl cadaverine (MDC) was employed without further purification. Column-chromatographic purification is recommended for the quantification of short chain carboxylic acids. For in situ derivatization the carboxylic acid sample solutions were applied to the HPTLC plates as bands with a maximum length of 10 mm. These were then „overlayed“ with MDC solution containing N,N’-dicyclohexylcarbodiimide to activate the acids. Short-chain carboxylic acids were separated on normal silicagel phases with toluene - ethyl acetate - ammonia mixtures as mobile phase. Stepwise and gradient developments allow the baseline separation. Long-chain carboxylic acids are better separated on RP-18 phases with acetonitrile-tetrahydrofuran mixtures and methanol as mobile phase.

J. Planar Chromatogr. 4, 325-326 (1991). TLC of carboxylic acids (no details) on silica impregnated with different concentrations of paraffin oil in petrol ether with acetic acid - acetonitrile 50:1. Detection after drying at 100-120 °C for 30 min. by spraying with a 0.1% dichloromethane or benzene solution of the 2-methyl-, 2-methoxy-, 2-chloro-, 2-bromo-, or 2-fluoro-derivatives of 9-isothiocyanatoacridine (most efficient: 2- methoxy- and 2-chloro-compounds.

J. Chem. Educ. 73, A4-A6 (1996). Presentation of dip reagents useful for visualization in TLC.