J. of Chromatogr. A 1281, 135-141 (2013). The use of detergents for the extraction, solubilization and purification of membrane proteins (MPs) is necessary due to their hydrophobic nature. Detergent quantification is essential to routine analysis because the concentration of amphiphiles is crucial in the crystallization process. HPTLC of detergents (in small quantities, bound to solubilized MPs) on silica gel with dichloromethane – methanol – acetic acid 80:19:1. The optimum HPTLC conditions were investigated using n-dodecyl-beta-D-maltoside (DDM), the most popular detergent for membrane protein crystallization. Quantification by fluorescence measurement at 366 nm using a Hg lamp. The calibration curve was linear in the range of 100-1600 ng of DDM in water and the limit of detection of was 50 ng/zone, which is the best LOD achieved to date for a routine detergent assay (not modified by the addition of NaCl, commonly used in protein buffers). In comparison with other techniques (colorimetry, GC, and FTIR) the HPTLC method has the advantage of no prior sample treatment for concentration or extraction, and no chemical labeling is required. In comparison with TLC, the HPTLC method is 100 times more sensitive. The HPTLC method is suitable for routine analysis, assay results are obtained within 3 hours and only few microliters of sample are needed.

J. Planar Chromatogr. 27, 97-101 (2014). HPTLC of myristicin (1) and linalool (2) in the leaf extracts of parsley, dill and celery on silica gel with petroleum ether - dichloromethane 3:7. Detection by spraying with vanillin reagent, followed by heating at 120 ºC for 5 min. Quantitative determination by absorbance measurement at 600 nm. Linearity was in the range of 5-21 μg/zone for (1) and 1-6 μg/zone for (2). The intermediate/interday/intra-day precisions were below 3 % (n=6). The LOD and LOQ were 1030 and 2000 ng/zone for (1) and 430 and 830 ng/zone for (2), respectively.

Braz. J. Microbiol. 44, 401-406 (2013). HPTLC of trichothecene in multiplex PCR isolates of Fusarium culmorum on silica gel with chloroform - methanol - water 45:5:1. Detection by dipping into 10 % aluminium chloride in methanol-water mixture, followed by heating at 110 ºC for 20 min. Qualitative determination at UV 366 nm._x000D_

CBS 111, 13-15 (2013). HPTLC of propolis on silica gel in a twin trough chamber with 8 mL of n-hexane – ethyl acetate – glacial acetic acid 5:3:1 and preconditioning with 5 mL hydrochloric acid (37 %) in the opposite trough using filter paper wetted with the hydrochloric acid shortly before chromatography. Migration distance was 65 mm. Detection under UV 366 nm after dipping in 0.5 % methanolic 2-aminoethyldiphenylborane reagent followed by drying and dipping in 5 % methanolic polyethylene glycol solution. Different types of German propolis were found, an orange, a blue and mixed types. Comparison with HPTLC fingerprints of the possible origin plants showed that the orange type most likely derives from Populus nigra. The blue type correlated to a certain extent with Populus tremula as well as both types with Aesculus hippocastanum L. Confirmed by MS the following substances were found in the orange type: pinocembrin, galangin, caffeic acid phenethylester and chrysin. The blue type contained p-cumaric acid and ellagic acid. Caffeic acid, quercetin and apigenin appeared in both types.

J. Trad. Chinese Veterinary Med. 47 (9), 32-33 (2012). In veterninary TCM Cangzhu Xianglian San powder is prescribed for the treatment of dysentery and diarrhea of livestocks. For quality control TLC on silica gel 1) for Atractylodes lancea, with petroleum ether (60-90°C) – acetone 9:2, detection by spraying with 10 % sulfuric acid in ethanol and heating mildly until the zones are clearly visible in daylight; 2) for Radix Aucklandiae, with cyclohexane – ethyl acetate – formic acid 15:5:1, detection by spraying with 10 % sulfuric acid in ethanol and heating mildly until the zones are clearly visible in daylight.

Chinese J. of Spectroscopy & Spectral Anal. 34 (4), 990-993 (2014). In recent years, some frauds were discovered on the drug market, e.g. chemical drugs with similar effect were illegally added to herbal TCM for hypertension which may cause a variety of adverse reactions and even endanger life. To ensure the safety of patients a method is presented for rapid screening of antihypertensive drugs. TLC on silica gel with dichloromethane – methanol – water 90:10:1, detection under UV 254 nm. Identification of nicardipine hydrochloride, doxazosin mesylate, propranolol hydrochloride and hydrochlorothiazide by comparison of the corresponding hRf values of standards. Qualitative analysis of the sample target zones by adding a few drops of silver glue solution onto each zone and then detection by surface enhanced Raman spectroscopy (SERS) using a portable Raman spectrometer at the integration time of 10 s and the laser power of 100 mW with a minimum detection amount of 5, 5, 50 and 50 ng, respectively. The TLC method was optimized regarding mobile phase, sample application volume, the concentration of silver glue solution, etc. The method was used for the analysis of 10 commercial products from the drug market. Two products contained illegally added nicardipine hydrochloride and doxazosin mesylate, and one product contained propranolol hydrochloride and hydrochlorothiazide.

J. Planar Chromatogr. 28, 42-47 (2015). HPTLC of (1) homoeriodictyol and (2) persicogenin in the methanol extract of the aerial parts of Rhus retinorrhoea and Rhus tripartita on silica gel with toluene - ethyl acetate - methanol 16:4:1. Quantitative determination by absorbance measurement at 293 nm. The hRF values of (1) and (2) were 30 and 48. Linearity was between 100 and 800 ng/zone for both, (1) and (2). The intermediate intra-day and inter-day precisions were below 2 % (n=6). The LOD and LOQ were 26 and 77 ng/zone for (1) and 31 and 92 ng/zone for (2), respectively. Recoveries were in the range of 98.9-99.5 % for (1) and 98.3-99.2 % for (2).

J. Planar Chromatogr. 28, 67-73 (2015). HPTLC of (1) rifampicin, (2) isoniazid and (3) piperine on silica gel with toluene – methanol – chloroform 7:3:3. Quantitative determination by absorbance measurement at 300 nm. The hRF values of (1) to (3) were 51, 24 and 81, respectively. Linearities were between 100 and 700 ng/zone for (1) and (2) and between 20 and 90 ng/zone for (3). The intermediate intra-day and inter-day precisions for (1) to (3) were below 2 % (n=6). The LOD and LOQ were 12 and 33 ng/zone for (1), 20 and 53 ng/zone for (2) and 5 and 10 ng/zone for (3). Recoveries for (1) to (3) were in the range of 99-101 %.