Proc. 6th Int. Symp. Instrum. Planar Chromatogr., (Interlaken 1991), Inst. Chromatogr., Bad Dürkheim, FRG, 231-234 (1991). The sample preparation system includes an OPLC chamber as an interface where samples of interest are migrated toward the column of an HPLC system. Another way of clean-up is the combination of conventional TLC with OPLC transfer. According to the chromatographic properties of unwanted sample materials, the impurities in front and/or starting zone can be eliminated while analyzable compounds from the localized area of the layer can be transferred to the HPLC system.

J. Planar Chromatogr. 28, 472-475 (2015). HPTLC of 17α-ethinylestradiol (extracted from water samples using a monolithic stir-bar) on RP-18 with methanol - acetonitrile - water 2:2:1. Detection by heating at 110 °C for 10 min followed by dipping into a mixture of sulfuric acid 98 % in water 1:49 for 1 s. After dipping the plate was heated again to 110 °C for 10 min. The hRF value for 17α-ethinylestradiol was 51.

Anal. Chim. Acta 236, 83-97 (1990). Summary of the state of art of various preparative planar liquid chromatographic methods for off-line and on-line sample application. Discussion of sample purification possibilities for PLC techniques. Suggestions in form of flow charts for purification and isolation strategies using forced-flow planar chromatographic techniques, such as OPLC, etc.

Trends Anal. Chem. 82, 100-108 (2016). Review on the application of microwave assisted extraction of bioactives from plant matrix. The review discussed microwave assisted extraction coupled with HPTLC as a technique for the analysis of individual phenolic antioxidants.

Chromatographia 30, 436-444 (1990). Investigation of the efficiency of diantipyrilmethane as a reagent for TLC of metals (titanium, zirconium, hafnium, rare earth elements, transition and platinum metals). Discussion of the peculiarities of the chromatographic behavior of metal diantipyrilmethanates and the mechanism of their TLC retention. Use of the method for the determination of metals based on complex formation directly in the sorbent layer or by liquid extraction. TLC on silica with organic solvent-mineral acid mixtures. Quantification by densitometry or spectrophotometry.

CBS 114, 13-15 (2015). To test the new HTpSPE–TOFMS screening, TLC of a pesticide mixture (acetamiprid, azoxystrobin, chlorpyrifos, fenarimol, mepanipyrim, penconazole, pirimicarb) in several plant matrices (cucumber, tomato, grape, apple extracts) on amino layer pre-treated by dipping in 2 % formic acid solution in acetonitrile and drying for 10 min. Development with 10 mL acetonitrile, migration distance 75 mm, drying 5 min; second development in the backwards direction with 10 mL acetone, migration distance 45 mm, drying 3 min. Detection under UV 254 nm, UV 366 nm and white light. For HTpSPE and μL-flow injection analysis–TOFMS the target analyte zone was eluted with the TLC–MS Interface into autosampler vials with acetonitrile – 10 mM ammonium formate 1:1, flow rate 0.2 mL/min, Elution time was 60 s. An HPLC system was coupled via a PEEK capillary and a nano-electrospray ionization interface to a TOFMS without an analytical column. The mean recovery for a pesticide mixture spiked into fruit and vegetable extracts was between 86 % and 116 % with %RSDs of 1.5–10 % (n = 5).

J. Planar Chromatogr. 3, 90-91 (1990). In situ measurement of the reaction mixture (1 mmol/L L-TAPA in 50 mmol/L Tris-HCL-buffer, pH 8.2, containing 25 mmol/L calcium chloride) and 0.1 mL of a trypsin containing sample on cellulose by absorbance at 405 nm. Sample size: 1 µL. - Densitometer response was linear in the concentration range from 10 to 200 µg of trypsin per mL; very good agreement between standard procedure and the microassay, good reproducibility.

J. Chromatogr. A 1515, 232-244 (2017). Characterization of lipids in both bone marrow (BM) and mineralized tissue (MT) compartments, and their potential implication in bone pathologies, involving sample preparation, lipid extraction and analytical issues using a small sample size (≤ 0.5 g of rat femurs). Two major issues in bone handling were addressed with two cleaning steps after BM removal and by adding a demineralization step to the overall lipid extraction protocol, to avoid potential contamination of the MT by marrow lipids and the poor accessibility of certain lipids from the MT. HPTLC of the major neutral and polar lipids provided excellent resolution for 15 standards, good precision (inter-day %RSD <13 %) and recoveries of the standards ranged between 76 and 122 %. The method was suitable for lipid determination in both BM and MT and reliable in terms of lipid quantification. Demineralization facilitates phosphatidylserine and cholesterol ester extractions from the MT. Confirmation of the HPTLC data by HPLC determination of fatty acids as naphthacyl esters in bone samples. The mineralized tissue seems to be more metabolically active than the bone marrow.