CBS 102, 2-3 (2009). A semi-automatic interface for hyphenation of TLC with mass spectrometry, which was based on the ChromeXtractor by Luftmann, is introduced. The interface is connected to a HPLC pump and the MS. By means of an extraction piston any target zone can be eluted from a TLC/HPTLC plate directly into the MS. Example: for identification of the zone at hRf 15 in a standard mixture of caffeine, paracetamol, and acetylsalicylic acid the mass spectrum of the zone is recorded. After subtraction of a background spectrum a mass spectrum free from system peaks is obtained, which shows mainly substance signals - here the mass signal m/z 195 [M+H]+ for caffeine.

Anal. Chem. 79, 5793-5808 (2007). HPTLC of phospholipids (phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, cardiolipin, sphingomyelin) on silica gel in a saturated chamber with chloroform-methanol - 2-propanol - triethylamine - 0.25 % potassium chloride solution 30:9:23:18:6. Detection by dipping in molybdenum blue reagent for 1 s and quantitative evaluation by densitometry. The sensitivity was in the range of 10 to 150 pmol/spot (depending on phospholipid acidity, hRf value, and ion polarity).

J. Planar Chromatogr. 22, 183-186 (2009). HPTLC of ethyl 8-oxo-5,6,7,8-tetrahydrothiazolo[3,2-a][1,3]diazepin-3-carboxylate (HIE-124) in plasma (with diazepam as internal standard) on silica gel with chloroform - ethyl acetate 4:1 with chamber saturation for 30 min. Quantitative determination by absorbance measurement at 265 nm. The limit of detection and quantification was 20 µg/L (40 ng/band) and 40 µg/L (80 ng/band), respectively.

Anal. Chim. Acta 599 (2), 302-309 (2007). HPTLC of minocycline on silica gel (impregnated with a 10 % (w/v) solution of disodium ethylene diaminetetraacetic acid (EDTA) with a pH of 9.0) with methanol - acetonitrile - isopropyl alcohol - water 10:8:1:1. Quantitative determination by absorbance measurement at 345 nm. The limit of detection was 3.7 ng/spot, recovery was 99.2 - 100.2 %, and precision was good with a %RSD of 0.4 %. The method was able to separate all degradation products (produced by acidic and basic degradation, oxidation and photodegradation) from the pure drug.

J. Planar Chromatogr. 22, 207-210 (2009). HPTLC of dexibuprofen on silica gel (prewashed with methanol) in a twin trough chamber with hexane - ethyl acetate - glacial acetic acid 15:5:1. Quantitative determination by absorbance measurement at 217 nm.

CBS 102, 10-12 (2009). HPTLC of diterpene lactones (ginkgolides A, B, C, and bilobalide) in aqueous Ginkgo biloba leaf extracts on silica gel (impregnated by dipping into a 4 % solution of sodium acetate in methanol - water 3:2 for 5 s followed by drying at room temperature for 1 h) with toluene - acetone 7:3 with chamber saturation for 20 min. After twofold development over 60 mm the plate is heated at 150 °C for 1 h for detection of active compounds. Quantitative determination by absorbance measurement at 254 and 400 nm. The correlation coefficients of the calibration curves were = 0.9971 and relative standard deviations were = 2.0 %. Intraday precision was 1.1-1.2 %, interday precision 1.1-1.3 % and recovery 98.5-104.6 %. The average content in leaves was 0.078 (in % of dry weight) for ginkgolide A , 0.072 for ginkgolide B, 0.076 for ginkgolide C, 0.062 for bilobalide and 0.29 % for total diterpene lactones.

J. Chromatogr. A 1216(25), 5052-5056 (2009). Diode array HPTLC of dequalinium chloride on silica gel with methanol - 7.8 % aqueous ammonium acetate 17:3. The hRf value was 58 for dequalinium chloride. Measurement of pure dequalinium chloride in the wavelength range from 200 to 500 nm showed several by-products. By densitometric scanning of a single track in absorption and fluorescence mode 600 spectra in the range from 200 to 1100 nm were measured within 30 s. Sample preparation for an ointment was done by dissolution in methanol. Quantitative determination by absorbance measurement from 315 to 340 nm, by fluorescence measurement from 355 to 370 nm, and by fluorescence measurement from 445 to 485 nm after derivatization with a solution of sodium tetraphenyl borate HCl in water. The linearity range of absorption and fluorescence measurements was between 10 and 2000 ng/zone. Sugar-containing preparations like liquids or lozenges can be reliably quantified only in fluorescence mode, otherwise further sample preparation is necessary.

60th Indian Pharmaceutical Congress PG-256 (2008). HPTLC of rosmarinic acid in Salvia officinalis on silica gel with toluene - ethyl acetate - formic acid 5:4:1. Quantitative determination by absorbance measurement at 328 nm. Linearity was 0.1-1.0 ng/mL, recovery was 99.4 %. The method was found suitable for routine quality control of the Salvia officinalis raw material.