Anal. Chem. 80, 2744-2750 (2008). TLC of mixtures of semipolar nitrogenated compounds as well as pharmaceutical drugs (allyl phenylamine, phenylamine, ethylpyridine, propanolol hydrochloride, and amlodipine besylate) on silica gel with ethyl acetate - hexane 1:4; detection under UV 254 nm. On-spot detection and analyte characterization via easy ambient desorption and sonic-spray ionization (EASI) and (tandem) mass spectrometry detection.

J. Chromatogr. A 1217 (23), 3711-3715 (2010). Oligosaccharides (derived from dextran, alginate, hyaluronan and chondroitin sulfate) were characterized by matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) directly on a normal phase TLC plate. The applied oligosaccharides were either commercially available or obtained from the polysaccharides by HCl-induced hydrolysis. TLC was followed by MALDI-TOF MS subsequent to matrix deposition. The high quality mass spectra obtained allow for unequivocal assignments. The high content of formic acid in the solvent does not cause major problems but is responsible for the partial formylation of the analyte and a minor N-acetyl loss from hyaluronan and chondroitin sulfate.

Chinese J. of Spectroscopy & Spectral Anal. 32 (7), 1790-1794 (2012). TLC is an efficient and economical alternative separation technique for those samples not suitable to be processed by HPLC due to no or low UV response of the compounds or their impurities. Fourier Transform Infrared Spectroscopy (FTIR) is a powerful technique of qualitative and semiquantitative analysis and of discrimination of functional groups towards pure organic compounds. FTIR coupled with TLC is a useful hyphenated technique for the analysis of complex organic mixture samples. In order to abate the interference from IR absorbance signal caused by conventional TLC stationary phases, plates coated with specially processed silver iodide particles are employed. Preparation of silver iodide by reaction of silver nitrate and potassium iodide and isolation of produced silver iodide particles (average size around 100 nm) by dialysis. The silver iodide plates are coated by precipitation method. TLC of bromophenol blue and rhodamine B on the prepared silver iodide plates, with methanol – acetone 1:3, detection in daylight and by in situ reflection FTIR.

J. Planar Chromatogr. 28, 402-406 (2015). Design of low-cost and relatively simple TLC-HPLC-MS set-up for sample elution from TLC plate to the HPLC or MS system. A prototype eluting device with a tubing for direct solute zone collection was constructed. The tubing consisted of a stainless steel capillary into which a Teflon capillary was placed. At the lower bottom of the stainless steel capillary the tip of the Teflon capillary formed a 3 mm deep dimple and the capillary walls were sharpened. The stainless steel capillary was disconnected from the prototype and by pressing the sharpened end on blotting paper a disc was resected which was located directly on the Teflon tip. Then the capillary was pressed against the adsorbent layer with the analyte zone. An advantage of the prototype was that this yould be done directly under the UV lamp without the need to mark the analyte zones on the layer. Like this a chip with the adsorbent layer was introduced into the capillary dimple. Then, the chip was covered with another disc of blotting paper (cut using the sharpened capillary). Subsequently, the stainless steel capillary was connected with the prototype, the injection valve was switched and the eluent flow was directed through the stainless steel capillary to the UV–VIS or MS detector. After the elution, the injection valve was switched again, the capillary was disassembled from the prototype and the remnant of the adsorbent layer was removed so that the capillary was ready for the next elution. The results obtained using the prototype device were compared to those obtained with the commercial TLC-MS Interface manufactured by CAMAG. Regardless of the device used the peak areas of the eluted analytes were correlated to their concentrations. However, the average peak area obtained with the TLC-MS Interface was considerably higher than that obtained with the prototype because the diameter of the tip of the stainless steel capillary was only 1 mm compared to the oval elution head (2x4 mm) of the TLC-MS Interface.

Marine Drugs 14(6), 108 (2016). A new, highly active alginate lyase (Cel32), isolated from the marine bacterium Cellulophaga sp. strain NJ-1, was incubated (10 mg/mL, 12-36 h, 30 °C, pH 7) with sodium alginate, related mannuronate and guluronate polymers and related oligosaccharides of different polymerisation degrees (PD 2-8), the reaction was stopped by boiling. TLC of the hydrolysates, purified by centrifuging and desalting, on unspecified layers with n-butanol – formic acid – water 4:6:1. Detection by spraying with ethanolic sulfuric acid 10 % and heating for 5 min at 130 °C. The enzyme was active on all substrates (except PD 2 and 3), cleaving them endolytically into oligomeric fragments (PD 2-4)._x000D_

J. Chromatogr. A 1526, 137-150 (2017). HPTLC of physalins from crude extracts of Chinese lantern (Physalis alkekengi L.) on silica gel with ethyl acetate – toluene – formic acid 35:15:1. Densitometric screening of physalins in absorption and in fluorescence mode after post-chromatographic derivatization with sulfuric acid reagent. Identification of the physalin L standard and its impurity, 2,3,25,27-tetrahydrophysalin A. Applying two successive plate pre-developments with methanol – formic acid 9:1 and methanol to avoid strong ion suppression caused by the developing solvent additive (formic acid), and to improve the sensitivity of HPTLC-MS/MS method combined with a slightly modified developing solvent ethyl acetate – toluene – formic acid 30:20:1. Non-targeted characterization of physalins from the same chromatographic zone and determination of physalin types by simultaneous hyphenation of HPTLC with a triple quadrupole and an ion trap mass analyzer. Demonstration of the performance of the HPTLC-densitometric and HPTLC–MS/MS methods for the analysis of physalins from aqueous reflux extracts. Observation of variations in physalin profiles and abundances in different parts of P. alkekengi harvested at different stages of maturity, showed that the husks are the most suitable plant part for P. alkekengi quality control.

J. Chromatogr. A 1579, 115-120 (2018). Description of a fast method for on-site detection of aflatoxins in moldy agricultural products using TLC combined with surface-enhanced Raman spectroscopy (TLC-SERS). On-site identification of four aflatoxins separated by TLC employing a small portable Raman spectrometer with gold colloids as the SERS-active substrate. Investigation of the application of the TLC-SERS technique to on-site qualification and quantification of aflatoxins in levels as low as 1x10−6 M shows that the technique has high sensitivity and selectivity to the object of interest and suits complex matrixes, such as the extracts from moldy peanuts. The method is suitable for fast on-site screening of aflatoxins in various agricultural products.

Elution with methanol. Determination by spectrophotometry at 280 nm.