J. Chromatogr. A 1390, 103-111 (2015). HPTLC-Vis-ESI-MS of 6 dyes in a commercially available dye mixture on silica gel with toluene up to a migration distance of 60 mm. Detection under white light and absorbance measurement using a multi-wavelength scan at 450, 500, 530 and 620 nm. Via the TLC-MS Interface the dye zones were eluted with methanol - ammonia formiate buffer (10 mM, pH 4.8) 19:1 at a flow rate of 0.1 mL/min into a single quadrupole mass spectrometer. Electrospray ionization mass spectra were recorded in full scan mode. Characteristic m/z values of dyes were used for quantitative measurements in SIM mode. The mean precisions (n=5) were below 10 % and a mean correlation was of 0.9975 for the 6 dyes. HPTLC-MS analysis revealed the incorrect assigment of components in two commercially available dye mixtures. Photooxidation degradation products were observed for interrupted workflows (for elutions after several days when the plate was kept in daylight).

Rapid Commun. Mass Spectrom. 29, 1242-1252 (2015). The paper describes the application of adding neon into helium for Direct Analysis in Real Time (DART) leading to plasma glow visualization to track the metastable gas distributions during surface scanning. The method allows for optimal selection of the coordinates for DART-MS analysis without loss in signal intensity. Visualization of the impact region of the excited gas stream is of high importance for further developments of planar chromatographic hyphenations with DART-MS.

J. Agric. Food Chem. 63, 9764-9769 (2015). HPTLC of the reaction products of 4-nitrophenyl β-D-glucoside (4NPGlc) with oleic acid, linoleic acid, and purified rice bran substrate catalyzed by rice transglucosidase Os9BGlu3 on silica gel with chloroform - methanol - 30 % ammonia 35:14:1. Detection by spraying with 10 % sulfuric acid in ethanol, followed by heating at 110 °C. The hRF value for the glucosyl conjugate was 53.

J. Liq. Chromatogr. Relat. Technol. 38, 1499-1506 (2015). RP-HPTLC of piperazine in pharmaceutical formulations on RP-18 with acetonitrile - water 3:2 modified with 1.5 % tetrafluoroborate. Quantitative determination by absorbance measurement at 247 nm. The hRF value for piperazine was 43. Linearity was in the range of 0.8-2.2 μg/zone. LOD and LOQ were 0.11 and 0.34 μg/zone. The intermediate precision was below 3.5 % (n=3). Recovery was between 99 and 103 %. Significant changes and improvements regarding the hRF value were observed when tetrafluoroborate was added to the mobile phase.

Trends Anal. Chem. 81, 51-62 (2016). Review on aspects to consider during calibration for quantitative chromatographic analysis such as noise and detector response, data acquisition and processing, calibration curve and inverse calibration.

J. Planar Chromatogr. 29, 30-37 (2016). HPTLC and pressurized planar electrochromatography (PPEC) of 20 amino acids on silica gel with acetonitrile – buffer pH 3.2 (citric acid – disodium hydrogen phosphate 2.28:1.44) 1:1 for HPTLC and acetonitrile – buffer pH 3.2 4:1 for PPEC. PPEC separation was performed at a polarization voltage of 1.0 kV for 25 min. Detection by spraying with ninhydrin solution, followed by heating in a warm air stream.

J. Liq. Chromatogr. Relat. Technol. 39, 308-311 (2016). HPTLC of trans-resveratrol in Physalis peruviana on silica gel with ethyl acetate – cyclohexane – n-butanol 9:9:2. Chemiluminescence was induced by dipping for 1 s into bis(2,4,6-trichlorophenyl)oxalate (TCPO) solution (50 mg TCPO in 36 mL n-butyl acetate, vigorously shaken for 20 min with 0.4 mL 35 % hydrogen peroxyde). After dipping, the_x000D_
wet plate was dried until no light reflection could be seen on the surface. The hRF value for trans-resveratrol was 78. The LOQ was 20 ng/zone.

J. Planar Chromatogr. 29, 99-107 (2016). Review of the application of TLC for the analysis of neutral and polar lipids found in parasite-infected and noninfected snails. Different aspects of the TLC procedure such as sample preparation, sample and standard application, layers and mobile phases, detection and quantification were reviewed. Compared to earlier reviews, the authors included lipophilic pigments as well as valuable information on numerous species of gastropod molluscs.