J. of Chromatogr. A 1218 (19), 2684-2691 (2011). Review on TLC/bioautography. Discussion of three versions of bioautography, i.e. contact, immersion and direct bioautography. The focus is put on direct bioautography and many applications are quoted, not only for testing various groups of compounds, but also for investigating biochemical processes and factors influencing bacterial growth. Various related methods can be included into direct bioautography, of which TLC-bioluminescence screening is the most promising one.

CBS 105, 2-4 (2010). TLC and HPTLC of reaction samples from small molecule lead development, on silica gel with mixtures of methanol and dichloromethane/ethyl acetate or ethyl acetate and heptane/cyclohexane (ratios depending on the compound mixtures). Detection with primuline or berberine reagent. Direct elution into the MS with the TLC-MS interface. Substances not detected by DAD can successfully be measured by ELSD detection coupled to TLC.

62nd Indian Pharmaceutical Congress Abstract No. F-263 (2010). TLC of desloratadine on silica gel with methanol – chloroform – toluene – ammonia 50:50:10:3. Quantitative determination by absorbance measurement at 254 nm. The hRf value was 61. The linearity was in the range of 150-750 ng/zone with r2 = 0.9997. The limit of detection was 21 ng/zone, whereas the limit of quantitation was 65 ng/zone.

Acta Chromatographica 22 (2), 259-265 (2010), DOI:10.1556/AChrom.22.2010.2.8. Description of a new, simple, precise, and accurate method for quantification of (-)-epicatechin in the leaves of Cassia fistula by HPTLC on silica gel with toluene – ethyl acetate – formic acid – methanol 205:3:1:1. Quantification by densitometry at 280 nm. The linearity was in the range of 200–800 ng/band. Method precision was 1.4 %RSD and instrumental precision 1.1 %RSD. Recovery was 98.1 % and specificity regarding matrix was given.

J. Planar Chromatogr. 24, 274-280 (2011). Presentation of new reagents and visualization methods which enable the detection of particular substances. The best of them provide high selectivity and low detection limits and lead to a reliable analysis of the developed chromatogram. Three groups of chemical reactions are used for detection: oxidation, reduction, and complexation, as well as precipitation of colored precipitates. Oxidation and reduction are most widely used due to their selectivity, which allows detection and identification of the separated substances. Like this the target substance can be selectively visualized, as for example antioxidants in complex natural matrices. Innumerable chemical, physical, and biological methods of visualization are known. Required are new, more efficient reagents fo a selective visualization of a defined part of a substance or, in some cases, for a specific determination of a specific substance. The article describes the detection of food ingredients, medicines and pharmaceuticals, organic compounds not present in food, and inorganic compounds.

J. AOAC Int. 93, 804-810 (2010). HPTLC of rutin on amino phase with ethyl acetate - formic acid - methanol - water 100:9:11:17 at room temperature. Detection by spraying with natural products reagent. Linearity was between 0.95 and 4.78 µg/zone. LOD and LOQ were 330 and 630 ng/zone, respectively. The %RSD for six replicates at three concentration levels was less than 3 %, while the recovery was between 97.3-103.3 %. For the three-dimensional image analysis of chromatograms images were taken from each plate using a HP flatbed scanner at an optical resolution of 300 dpi in normal mode. The pictures were stored in TIFF file format. Evaluation was performed using Melanie 7.0 software. Following automatic detection of the zones the program computed the 3D image of a selected region from the HPTLC plate. The volume of the resulting cone-shaped zone was used as numerical data to construct the calibration curve.

J. Planar Chromatogr. 24, 487-490 (2011). HPTLC of vitamin D3 in fish oil after saponification and purification on silica gel with chloroform - diethyl ether 9:1 with chamber saturation for 20 min. Quantitative determination at 280 nm. Linearity was between 200 and 1000 ng/band. The LOD and LOQ were 29 and 232 ng/band, respectively. The repeatability (RSD) was 4.6 %; the %RSD for intermediate precision was 0.9; the %RSD for intra-day precision (n = 6) was between 2.9-5.9 % and the %RSD for inter-day precision (n = 6) was between 3.2-6.4 %. Recovery was 97.6 - 104.2 % with a %RSD of 3.9 - 4.8 %.

J. Liq. Chromatogr. Relat. Technol. 34, 1850-1869 (2011). HPTLC of pipazethate (1) and its degradant 10H-pyrido[3,2-b][1,4] benzothiadiazine-10-carboxylic acid (2) on silica gel with chloroform - diethylamine - methanol 94:1:5. Quantitative determination by absorbance measurement at 225 nm. The hRf values of (1) and (2) were 35 and 28, respectively. Linearity was between 2-9 µg/zone for (1) and 1-6 µg/zone for (2). Limits of detection and quantification were found to be 53 and 180 ng/zone for (1), and 40 and 130 ng/zone for (2), respectively. Recoveries (by standard addition) were 100.1 % for (1) and 99.5 % for (2). Comparable results were obained with a validated HPLC method.