CBS 116, 11-12 (2016). HPTLC of lactose in milk, yoghurt, and instant sauce on silica gel with acetonitrile – water 3:1 (with 0.1 % trifluoroacetic acid) to the migration distance of 5 cm. Detection by spraying with aniline-diphenylamine-phosphoric acid reagent (2 g diphenylamine and 2 mL aniline in 80 mL methanol, 10 mL of o-phosphoric aicd 85 %, filled up to 100 mL) and heating for 10 min at 120 °C. Evaluation under white light. Elution of zones from the underivatized plate into ESI-MS with acetonitrile – water 19:1 (with 0.1 % formic acid) and detection in positive ionization mode. The method is suitable for semiquantitative determination of lactose by image evaluation and allows for confirmation of lactose-free products as such.

CBS 113, 9 (2014). HPTLC of caffeine in energy drinks (applied neatly without sample preparation) on silica gel MS-grade with 2-propanol – n-heptane – water 7:3:1. Detection under UV 254 nm and by dipping into anisaldehyde reagent. Quantitative evaluation by absorbance measurement at 273 nm. The hRf of caffeine was 55. For confirmation of results, zones were eluted with the TLC-MS Interface (acetonitrile – water 19:1 with 0.1 % formic acid, flow rate 0.1 mL/min) and directly transferred to a mass spectrometer and measured in ESI(+) full scan mode (m/z 100 – 500).

J. Food Compos. Anal. 48, 25-33 (2016). In this study 353 samples of different varieties and different commercial products were analyzed by HPTLC and UV absorbance. HPTLC of the acetonic extract of kava powder on silica gel with hexane – dioxane 4:1 without chamber saturation over a distance of 85 mm. Detection under UV 254 nm and 366 nm. Densitometric evaluation and determination of the ratios kavain/total kavalactones (K/KL) at 254 nm and flavokavins/kavalactones (FK/KL) at 366 nm. Derivatization by dipping in anisaldehyde sulfuric acid reagent (10 mL sulfuric acid, 170 mL methanol, 20 mL acetic acid, 1 mL anisaldehyde) and heating at 100 °C for 3 min. The results showed that noble varieties suitable for daily consumption of kava are characterized by high K/KL and low FK/KL.

J. of Chromatogr. A 1415, 155-160 (2015). Presentation of a technique for direct analysis of raw samples by TLC coupled with electrospray ionization mass spectrometry (ESI-MS) instead of conventional MS analysis, which for raw samples commonly requires time-consuming and laborious sample pretreatment and separation using HPLC or GC. The analytes of interest could be extracted, ionized and detected by ESI-MS with much reduced matrix interference because the interfering compounds were retained by the sorbent material of the TLC plate. Demonstration by applying in direct analysis of samples containing common interfering compounds, e.g. salts and detergents. Rapid detection and quantification of target analytes in raw samples showed that the TLC-ESI-MS method was simple, rapid, efficient and could be effectively applied in offline and online separation and detection of different components in raw samples, e.g. plant extracts.

J. Agric. Food Chem. 64, 8838-8847 (2016). HPTLC of free fatty acids produced after treatment of vegetable oils with crude lipase extracts from germinated seeds of Adansonia suarezensis, Adansonia grandidieri, Moringa oleifera, Moringa drouhardii, Jatropha mahafalensis, and Jatropha curcas seeds on silica gel with hexane – diethyl ether – acetic acid 70:30:1. The hRF value of free fatty acid was 43.

Chinese J. of Drug Evaluation 32 (4), 193-194 (2015). Fortune Paulownia leaf, the dry leaf of Paulownia fortunei (Seem.) Hemsl, is a TCM raw material used for treatment of carbuncles, furuncles, trauma, hemorrhage, etc. For quality control, TLC of its extracts on silica gel previously impregnated with 1 % iodine in dichloromethane and developed with cyclohexane – ethyl acetate – glacial acetic acid 20:6:1, detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 ºC until the zones are clearly visualized, viewing (A) in white light and (B) under UV 366 nm. Identification by fingerprint comparison with the standards oleanolic acid (hRf 67) and ursolic acid (hRf 60) and the reference raw material in parallel.

J. Chromatogr. A 1465, 197-204 (2016). Demonstration of a strategy for an improved quality control of propolis shown on the example of 30 French propolis samples based on evaluation of their HPTLC fingerprints in combination with selected mass signals obtained by desorption-based scanning mass spectrometry (MS). Separation of the French propolis sample extracts by HPTLC on silica gel with n-hexane – ethyl acetate - acetic acid 5:3:1 and on RP phase with n-hexane – toluene – ethyl acetate – formic acid – acetic acid 16:6:10:3:3, both in twin-trough chambers with 37 % hydrochloric acid applied on a filter paper in the second trough of the chamber. Analysis of the fingerprints, obtained by two different detection modes, i.e. after (1) derivatization with NP and PEG reagents and fluorescence detection at UV 366 nm and (2) scanning direct analysis in real time (DART)-MS, by multivariate data analysis. The best classification was obtained using both methods, RP-HPTLC-FLD and RP-HPTLC-DART-MS, in combination with pattern recognition techniques, such as principal component analysis. Observation of the characteristic patterns from the two types, in which all investigated French propolis samples were divided. Identification of phenolic compounds, such as caffeic acid, p-coumaric acid, chrysin, pinobanksin, pinobanksin-3-acetate, galangin, kaempferol, tectochrysin and pinocembrin, as characteristic marker compounds of French propolis samples. Confirmation of the presence of two botanically different types of propolis, known as the blue and orange types.

Food Chem. 239, 831-839 (2018). HPTLC of saffron on silica gel with 1-butanol – acetic acid – water 4:1:1. Qualitative identification at UV 254 nm. The hRf values of the nine detected zones (crocins and picrocrocin derivatives) were 19, 29, 43, 56, 63, 67, 80, 85, and 96. Captured images were imported to the MATLAB program for pattern recognition and discrimination between different saffron samples on the basis of their soil electro-conductivity values as indicator of soil salinity. The data pre-processing included elimination of chromatographic artifacts such as baseline drifts and spot misalignment.