J. Liq. Chromatogr. & Relat. Technol. 29, 2425-2436 (2006). HPTLC and TLC of phenyl isothiocyanate derivatives of biogenic amines (2-phenylethylamine, tyramine, octopamine, dopamine, adrenaline, histamine, tryptamine, putrescine, spermidine, spermine, and calamine) on silica gel and RP-18 in a horizontal chamber saturated for 30 min with hexane - dioxane 1:1; 1:2; and 2:3; hexane - ethanol 1:1, methanol - dioxane 2:1, and hexane - dioxane - toluene 1:1:1. Prechromatographic derivatization with PITC directly on the plate. Detection of NP-TLC plates (silica gel) by spraying with a mixture of sodium azide and starch solution. For RP-TLC sodium azide solution with starch was incorporated into the mobile phase, and then the plates were exposed to iodine vapor. The stability of the resulting white zones on a violet-grey background lastet for several minutes. The results of the detection limits proved to be advantageous to other commonly used detection techniques (UV and iodine chamber).

Biomed. Chromatogr. 10, 225-227 (1996). TLC on silica with chloroform - acetone - ethyl acetate - methanol 136:64:4:1. Detection by spraying with ethylenediamine - methanol - potassium ferricyanide (1.5%) 1:3:1, incubating for 5 min at 60°C and in the dark at room temperature for 15 min. Quantification by fluoro densitometry at 415/>485 nm.

International Journal of ChemTech Research 2(2), 1188-1193 (2010) TLC on silica gel with chloroform - ethanol 7:3. The hRf value of tramadol HCl was 48 and of paracetamol 85. Densitometric evaluation at 254 nm. The method was linear over a concentration range of 2.5-32.5 µg/band for tramadol and 10-50 µg/band for paracetomol. The recovery was 100.7-101.8 %. There was no intereference with excipients from the dosage form.

International Journal of Molecular Sciences 3(7), 755-763 (2002). The introduction reviews in details the history of the Rm value, which means log(1/Rf – 1), and of its use to calculate the partition coefficient. For 10 aminoalkanethiosulfuric acids, 8 mercaptoalkanamines and 3 aminoalkyl disulfides, Rf and Rm values were determined by reverse phase TLC on silica gel (previously dessicated and impregnated with octanol – chloroform 1:19), with binary mixtures of methanol and 0.2 M ammonium acetate buffer pH 6.0 in different proportions. Detection by exposure to iodine vapor. Rm values were extrapolated to 100 % water, which was compared to the log P values obtained with the shake-flask method and with theoretical calculations.

J. Planar Chromatogr. 2, 133-137 (1989). The ion-pairing characteristics of tetraalkylammonium salts and cetrimide and also of tricaprylmethylammonium chloride were studied. In eluents containing 50% methanol and 0.05 mol/L ion-pairing reagent, the Rf values of salicylic acid derivatives displayed the following sequence: tetrabutylammonium hydrogensulfate > cetrimid > tricaprylmethylammonium chloride. On reversed-phase layers, the pH had no effect on retention. With increasing concentration of methanol the retention of the compounds decreased. TLC on RP-8 and (HPTLC) silica with mixtures of water and organic solvents containing NaCl and Bitton-Robinson buffer. Detection under UV 254 and 366 nm.

J. Planar Chromatogr. 10, 298-302 (1997). Study of the retention behavior of formanilide and 4-substituted acetanilides on starch and cellulose using aqueous mobile phases with methanol, acetonitrile, acetone, and 1-propanol as modifiers. Also published in Proc. 9th Internat. Symp. Instr. Chromatogr., Interlaken, April 9.-11., 79-88 (1997).

Part A. Elsevier Scientific Publishing Comp. 4, (1982). Chapter 3. Thin-layer chromatography of biogenic amines. TLC is an important technique for the analysis of biogenic amines. It plays an adjunctive role as a separation technique when biogenic amines are analyzed by fluorescent, mass spectrophotometric, radioenzymatic and radiochemical methods. The new technology associated with HPTLC, e.g. preformed multichannel plates improves the efficiency and specificity of radioenzymatic assays. The new technology of HPTLC, the convenience of scanning densitometers, the increasing sophistication of sample application and TLC plate development have given renaissance to the analytical technique of TLC.

J. Chromatogr. 307, 145-153 (1984). Activated (+)- and (-) benzoxaprofen are both shown to be very sensitive and stable chiral fluorescence markers, applicable to thin-layer chromatography as well as to high-performance liquid chromatography. TLC on silica with a) toluene - dichloromethane-THF 5:1:1; 2) toluene-chloroform - THF 5:4:1. Detection by in situ fluorometry (excitation wavelength at 313 nm).