J. Planar Chromatogr. 3, 236-242 (1990). HPTLC separation of anabolic steroids on silica; androgens and gestagens with cyclohexane - ethyl acetate - ethanol 24:16:1 in the first direction and chloroform - acetone 9:1 in the second direction; estrogens with chloroform - benzene - ethanol 36:4:1 in the first direction and hexane - ether - dichloromethane 4:3:2 in the second. An additional confirmation of the identity of the steroids is possible by HPTLC on silica RP-18 with methanol - water - toluene 13:4:1 in the first direction and hexane - dichloromethane - acetonitrile 8:2:1 in the second. Detection by fluorescence after immersion in a 5% sulfuric acid - ethanol solution for 30 sec and viewing under UV 366 nm. Method for routine HPTLC analysis.

J. Planar Chromatogr. 5, 396-407 (1992). Review with 82 references of the advances in the techniques and applications of TLC for the separation, detection, and quantification of steroids for the past ten years, focussing mostly on industrial steroid analysis. Methods prescribed in the latest editions of the USP, BP, and Ph. Eur. are considered in particular. To differentiate between the concepts and principles of the various pharmacopoeias, the TLC methods used for identification and purity testing of steroid raw materials and formulated products are compared with special regard to the separation systems prescribed, the methods used for visualization and quantification. 1. Introduction; 2. Separation Methods (separation of pharm. important steroids on chem. bonded phases, separation of steroid epimers on chem. modified silica stationary phases, reverse phases paired ion TLC of steroids); 3. Special Techniques (separation, detection and quantification); 4. Recent Analytical Applications; 5. The role of TLC in industrial steroid analysis, with emphasis on Pharmacopoeial prescriptions.

J. Chinese Herb Med. (Zhongcaoyao) 27, 422-426 (1996). TLC of amino acids on silica with chloroform - methanol - formic acid 35:15:1. Detection by spraying with 0.2% ninhydrin in ethanol. TLC of steroids on silica with benzene - petrol ether 4:1. Detection by spraying with acetic anhydride - sulfuric acid - ethanol 1:1:10 and heating at 100°C for 15 min.

J. Planar Chromatogr. 26, 56-61 (2013). TLC of ofloxacin (1) and dexamethasone (2) on silica gel with methanol - 0.01 M phosphate buffer 2:3 and pH adjusted to 5 with orthophosphoric acid. Quantitative determination by absorbance measurement at 300 nm for (1) and 240 nm for (2). The hRf values for (1) and (2) were 22 and 60, respectively. Linearity was in the range of 1-6 µg/zone for both (1) and (2). The LOD and LOQ were 260 and 870 ng/zone for (1) and 220 and 740 ng/zone for (2), respectively. Average recovery (by standard addition) for (1) and (2) was 99.2 %. Intermediate/interday/intra-day precision was below 2 % (n=3). The method showed comparable results with a validated HPLC method.

(Hungarian). Magyar Kémiai Folyóirat 95, 33-37 (1989). TLC of 4-androsten-3,17- dione and testosterone on silica with ethyl ether - toluene 2:1. Visualization with ethanol - phosphoric acid 1:1 reagent.

J. Planar Chromatogr. 11, 305-308 (1998). Investigation of the chromatographic behavior of dexamethasone, prednisolone, and other representative corticosteroids. - 12 Different mixtures of organic solvents were compared to assess their efficiency as mobile phases for the separation of 18 glucocorticosteroids by TLC. Optical evaluation of the plates after treatment with 4 different spray reagents then revealed that the combination of choice for optimum separation and detection was chloroform- methanol 23:2, or chloroform - acetone 9:1 and a mixture of 2,4-dihydroxybenzaldehyde, sulfuric acid, and acetic acid as spray reagent. The specificity of these chromatographic conditions was assessed by analysis of 35 anabolic steroids and 10 other veterinary drugs. No significant interferences were found.

CBS 115, 2-4 (2015). HPTLC of propolis tinctures and standards estrone, 17-estradiol, 17-ethinylestradiol, estriol, bisphenol A, 4-n-nonylphenol, and caffeic acid methyl ester on RP-18W with n-hexane – toluene – ethyl acetate 8:3:2 to a migration distance of 7 cm. For the HPTLC-pYES bioassay the plate was dipped into a yeast cell suspension and incubated for 3 h. Biodensitometric evaluation by fluorescence measurement at 365 nm with a cut-off filter of 400 nm. Elution of the bioactive zones with methanol – ammonium formate buffer (10 mM, pH 4, 49:1) into a ESI-MS. The LOD for 17-estradiol was 0.2 pg/zone and the LOQ 0.5 pg/zone. With this method estrogen effective substances can be detected with no or minimal sample preparation.

J. Planar Chromatogr. 5, 229-233 (1992). TLC of a bis quaternary ammonium steroid on silica with lithium perchlorate (20%) in water - 2-propanol - glycerol 5:90:5. Separation of the decomposition products with sodium iodide (40%) in water - 2-propanol - acetonitrile 5:90:5. Detection with iodine vapor resp. by immersion into a solution of iodine (0.25%) in chloroform - methanol 1:1 (decomposition products). TLC of an estrogen and a progestogen on silica with toluene - ethyl acetate - acetic acid 80:20:3. Quantification by scanning in fluorescence/reflection mode. Practical hints on application, development, detection, and densitometric evaluation; if performed carefully, TLC results are of the same quality as those from HPLC or GC.