International Laboratory News, February, 8A-8B (1994). HPTLC of clenbuterol in various matrices on silica in horizontal developing chamber from both sides with ethyl acetate - methanol - acetic acid 8:1:1 with chamber saturation. Derivatization by spraying with Bratton-Marshall reagent (first 1% sodium nitrite in 1 N HCl, then 0.4% N-(1-naphthyl)-ethylenediamine dihydrochloride in methanol). Quantification by densitometry (absorbance) at 525 nm. Detection limit 2.5 ng; determination limit 10 ng. Further betablockers can be detected with this method, like atenolol at hRf 8, salbutamol at 14, propranolol at 25, clenbuterol at 40 and labetalol at 44. Sample preparation includes deproteinization, defattening and final extraction from an alkaline aqueous phase. Very fast method - chromatography of 18 resp. 36 samples within 10 min.

Br. using gymnestrogenin as reference. Indian J. Pharm. Sci. 66 (2), 242-244 (2004). HPTLC of gymnestrogenin in Gymnema sylvestre on silica gel with chloroform - methanol 9:1. Quantitative determination by absorbance measurement at 293 nm. Linearity was in the range of 4-10 µg. A gymnestrogenin content of 1.11 % was found in the test sample. Average percentage recovery was 99.1 ±0.27. The proposed method is precise and sensitive and can be used for detection, monitoring, and quantification of gymnestrogenin in Gymnema sylvestre.

56th IPC 2004, Abstract No. GP-36. HPTLC for the standardization of gallic acid in alcoholic extracts of Aphanamixis polystachya (Meliceae) on silica gel with toluene - ethyl acetate - formic acid - methanol 15:15:4:1. Rf value of gallic acid was 0.45, linearity was 15 - 75 mg/mL. Formulations were found to contain 9.56 % of gallic acid. Gallic acid is the main phenolic compound and can be used for standardization of the crude drug.

J. Liq. Chrom. & Rel. Technol. 26, 3453-3462 (2003). HPTLC of caffeine and acetaminophen on silica gel in a saturated twin-trough chamber with ethyl acetate - glacial acetic acid 19:1. Quantification at 254 nm. Diphenhydramine, pseudoephedrine, and acetaminophen were well separated from the caffeine zone. Precision (relative standard deviation) was 1.19 %; limit of detection was 0.2 µg for caffeine and 0.08 µg for acetaminophen; precision of duplicate samples (RSD) ranged from 0.95 to 7.56 %.

59th Indian Pharmaceutical congress F-11, 392, (2007). HPTLC oleanloic acid from seeds of Achyranthes aspera on silica gel with n-hexane - ethyl acatete - acetic acid 30:201. Detection by spraying with anisaldehyde - sulphuric acid reagent. Densitometry at 530 nm for quantification of oleanolic acid. Linearity was between 200 and 1200 ng/zone. The plant tree was found to contain 0.34 % oleanloic acid. The method can be used for routine quality control.

J. Agric. Food Chem. 56, 8050-8057 (2008). HPTLC of [2-14C]-cymoxanil in the cultures (medium and mycelium) and in the cell-free extracts of Botrytis cinerea on silica gel with hexane - ethyl acetate - acetic acid 70:30:1. The most polar products were separated on RP-18 (impregnated with a methanolic solution of tetrabutylammonium bromide 70 mM and dried at 80 °C for 5 min) with phosphate buffer (0.01 M, pH 6) – methanol 11:9. Detection by autoradiography. The hRf value of cymoxanil was 35 on silica gel. Different metabolites were detected using both stationary phases.

Encyclopedia of Chromatography Third Edition 1, 2319-2322 (2009). The author describes the techniques and instruments for the detection and quantification of radiolabeled substances in thin-layer radiochromatography (TLRC) or radio-TLC. In detail, film autoradiography, liquid scintillation counting (LSC), storage phosphor imaging and in situ radioactivity scanning are described. The instruments for these methods are highly automated providing significant advantages in radiopharmaceutical purity determination, metabolism studies and many other investigations.

J. Chromatogr. A 1218 (19), 2775-2784 (2011). A multi-enzyme inhibition assay (HPTLC-EI) based on rabbit-liver esterase (RLE) and cutinase following HPTLC allows detection of thiophosphate pesticides. Because choline esterase inhibition is more effective after conversion of thiophosphate thions into their corresponding oxons, a pre-oxidation step was added to the HPTLC-EI assay by using bromine vapor. Bromine was more effective than iodine or UV irradiation for oxidation. It increased the inhibitory strength of parathion, parathion-methyl, chlorpyrifos, chlorpyrifos-methyl, and malathion by 2 orders of magnitude. In contrast, bromine oxidation of organophosphate and carbamate insecticides resulted in a slight reduction in their inhibition factors, due to partial bromination and degradation of the parent compounds. Bromine oxidation increased the inhibition factors for demeton-S-methyl and propoxur. The HPTLC-EI system was applied to the analysis of apple juice and water samples spiked with paraoxon (0.001 mg/L), parathion (0.05 mg/L), and chlorpyrifos (0.5 mg/L) and the mean recoveries were 95-106 % and 91- 102% for RLE and cutinase, respectively.