J. of Global Trad. Chinese Med. 5 (5), 362-363 (2012). Yimucao ointment is a TCM preparation for curing irregular menstruation and postpartum blood stasis. It was found recently that degradation of stachydrine, the active component in the medicine appeared during its storage. In order to improve the quality control of the medicine the stability and influencing factors during its storage have been investigated. TLC on silica gel with n-butanol – ethyl acetate – hydrochloric acid 8:1:3, detection by heating at 105 °C for 15 min firstly and then spraying with 1 % ferric chloride in ethanol – 5 % potassium iodobismuthate solution 1:10 until the zones were visible in daylight. Quantitative determination of stachydrine by densitometry at 510 nm. Investigation of the influence of temperature and light on the content of stachydrine in Yimucao ointment showed that light is the primary reason causing degradation during its storage.

Chinese J. of Lishizhen Trad. Med. & Pharm. 22 (1), 100-101 (2011). Yangning capsules are a herbal TCM for treating skin pruritus caused by various reasons. For quality control, TLC on silica gel 1) for Radix Saposhnikoviae and Radix Angelicae Sinensis, with petroleum ether (60-90 °C) – ethyl acetate 4:1, detection under UV 366 nm; 2) for Radix Glycyrrhizae, with ethyl acetate – formic acid – glacial acetic acid 15:1:1:2, detection by spraying with 10 % sulfuric acid in ethanol and heating at 105 °C, viewing under UV 366 nm; 3) for Cortex Dictamni, with toluene ethyl acetate – formic acid 25:15:1, detection by spraying with 5 % vanillin in sulfuric acid – ethanol 1:4 and heating at 105 °C, viewing in daylight. Quantification of matrine and oxymatrine by HPLC.

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, 132-139 (2014). HPTLC of levetiracetam on silica gel with toluene - ethyl acetate - methanol 2:1:1. Quantitative determination by absorbance measurement at 204 nm. The hRF value for levetiracetam was 50. Linearity was in the range of 1-1000 ng/zone. The intermediate/interday/intra-day precisions were below 1 % (n=6). The LOD and LOQ were 30 and 100 ng/zone, respectively. Recovery was between 99.2 and 100.9 %.

Trends in Chromatography 8, 131-135 (2013). Based on the Minilab TLC screening methods two individual and one simultaneous HPTLC methods for quantification of lumefantrine and artemether were developed. HPTLC of artemether, lumefantrine, and both substances in a combined tablet formulation on silica gel with ethyl acetate - glacial acetic acid - toluene 2:1:9 with chamber saturation. Quantitative absorbance measurement of lumefantrine at 254 nm. For artemether, detection by spraying with methanol - 96 % sulfuric acid 19:1 and heating at 100 °C for 5 minutes, evaluation in daylight and quantitative absorbance measurement at 610 nm. With the simultaneous method artemether zones were detected by heating at 160 °C for 5 min, and after cooling absorbance measurement at 254 nm was performed. This is a novel, reagent-free detection method based on thermochemical activation of fluorescence quenching. Precision (%RSD) for the artemether individual method was 0.1-0.6 % and recovery 98-103 %. Precision (%RSD) for the lumefantrine individual method was 0.9-1.8 % and recovery 100-102 %. With the simultaneous method the hRF was 34 for lumefantrine and 61 for artemether, precision (%RSD) was below 3 % and recovery was 98-100 %.

J. Chromatogr. A 1390, 103-111 (2015). HPTLC-Vis-ESI-MS of 6 dyes in a commercially available dye mixture on silica gel with toluene up to a migration distance of 60 mm. Detection under white light and absorbance measurement using a multi-wavelength scan at 450, 500, 530 and 620 nm. Via the TLC-MS Interface the dye zones were eluted with methanol - ammonia formiate buffer (10 mM, pH 4.8) 19:1 at a flow rate of 0.1 mL/min into a single quadrupole mass spectrometer. Electrospray ionization mass spectra were recorded in full scan mode. Characteristic m/z values of dyes were used for quantitative measurements in SIM mode. The mean precisions (n=5) were below 10 % and a mean correlation was of 0.9975 for the 6 dyes. HPTLC-MS analysis revealed the incorrect assigment of components in two commercially available dye mixtures. Photooxidation degradation products were observed for interrupted workflows (for elutions after several days when the plate was kept in daylight).

CBS 116, 9-10 (2016). HPTLC of herbal slimming drugs and the standard orlistat on silica gel with toluene – ethyl acetate 4:1 with chamber saturation (with filter paper) to the migration distance of 70 mm. Detection by dipping in phosphomolybdic acid reagent (5 g in 100 mL ethanol) and heating at 110 °C for 5 min. Evaluation under UV 254 nm, 366 nm and white light. Quantitative determination by absorbance measurement at 195 nm before derivatization to detect illegally added orlistat in the herbal drugs. The LOD of orlistat standard was 70 ng/band.

CBS 117, 11-12 (2006). For the rapid control of the fish species escolar (Lepidocybium flavobrunneum) by determination of the indigestible wax esters, HPTLC on silica gel with n-hexane – toluene 7:3 with chamber saturation for 10 min, migration distance 60 mm. Detection by dipping in aqueous Rhodamine B reagent (0.025 %), evaluation under UV 366 nm. Quantitative determination by fluorescence measurement at 366/>400 nm with the Hg lamp. The hRF value of oleyl oleate was 30 and of stearyl stearate 40. The mean recovery rate (104 %) was determined by analyzing salmon samples spiked to contain 20 % wax esters. The wax ester content of an escolar sample was 18-22 % (n=3). The repeatability was <5 % and the mean laboratory precision 3 %.