J. of Chromatogr. A 1249, 226-232 (2012). Ultrathin-layer chromatography (UTLC) is a recently developed analytical method intended for compact, rapid separations of nanolitre analyte volumes. However, new measurement techniques compatible with the millimetre length scales and rapid separation dynamics observed in UTLC are required for optimizing the performance of this method. A measurement system which records UTLC separations in full color with 32 µm spatial resolution and 33 ms temporal resolution has been designed, implemented and characterized. It features analysis of multiple tracks per plate, filtering of analyte zones by color, and automatic generation of time-resolved figures. By capture a wealth of information from a UTLC separation it provides insight into UTLC physics and improves the analytical performance.

J. Liq. Chromatogr. Relat. Technol. 35, 1497-1516 (2012). The authors reviewed stationary phases, solvent systems, and detection reagents developed for the analysis of amino acids. Polar and non-polar layers as well as impregnated layers mainly with metal ions and also with chiral agents were described for the separation and identification of amino acids. On the other hand, over fifty mobile phases were reviewed for the analysis of amino acids, with a recent tendency in the use of surfactants as less toxic reagents. Methodologies for the separation of amino acid enantiomers, such as the use of beta-cyclodextrin as chiral mobile phase as well as derivatization methods such as iodine azide reaction to enhance sensitivity in detection were also described. TLC has a privileged position due to its simplicity, convenience, and cost-effectiveness for separation of amino acids.

J. Liq. Chromatogr. Relat. Technol. 35, 1731-1749 (2012). HPTLC of atazanavir sulfate (1) and ritonavir (2) in fixed dosage on silica gel with toluene – methanol – glacial acetic acid – ethyl acetate 14:1:3:4. Quantitative determination by absorbance measurement at 254 nm. The hRf values of (1) and (2) were 50 and 63, respectively. Linearity was 30-300 ng/zone for (1) and 10-100 ng/zone for (2). The intermediate/inter-day/intra-day precision was 0.3 % for (1) and 0.7 % for (2) (n=6). The limit of detection and quantification was 16 and 49 ng/zone for (1) and 18 and 55 ng/zone for (2), respectively. Recovery (by standard addition) was 99.9 % for (1) and (2). The results were in accordance with those by a validated HPLC method.

Chinese J. of Inform. on TCM 17 (12), 48-50 (2010). Fuyanshuan suppository is a herbal TCM preparation for heat clearing, detoxifying, eliminating stagnation, regulating the flow of vital energy and invigorating the circulation of blood. For quality control TLC of the extracts of the preparation 1) for Ajuga becumbens Thunb., on silica gel with cyclohexane - chloroform – ethyl acetate – glacial acetic acid 40:10:16:1, detection by spraying with 10 % sulfuric acid in ethanol and heating at 100 °C, evaluation under UV 366 nm or daylight; 2) for Lonicera japonica, on silica gel with chloroform – acetone – formic acid 3:2:1, detection by exposure to daylight for 10 min and viewing under UV 366 nm.

J. Chil. Chem. Soc. 57, 1033-1035 (2012). HPTLC of propanolol hydrochloride (1) and flunarizine dihydrochloride (2) in combined dosage form on silica gel with methanol - toluene - ammonia 14:6:1. Quantitative determination by absorbance measurement at 267 nm. The hRf of compounds (1) and (2) were 63 and 48, respectively. Linearity was in the range of 800-4800 ng/zone for (1) and 200-1200 ng/zone for (2). Limits of detection and quantification were 25 and 75 ng/zone for (1) and 16 and 48 ng/zone for (2), respectively. Intermediate/intra-day/inter-day precision was below 2.0 % (n=6). Recovery for both (1) and (2) was between 99.3 and 100.9 %.

J. Planar Chromatogr. 25, 456-462 (2012). HPTLC of loratadine (1) and desloratadine (2) on silica gel with methanol + 1 drop ammonia. Quantitative determination by absorbance measurement at 254 nm. The hRf values of (1) and (2) were 76 and 20, respectively. Linearity was in the range of 250-850 ng/band for (1) and 100-1000 ng/band for (2). Limits of detection and quantification were 90 and 250 µg/band for (1) and 30 and 100 µg/band for (2), respectively. Intra- and inter-day precisions were found to be less than 2 %. Recoveries were between 97.8 and 101.5 % for both (1) and (2).

J. Planar Chromatogr. 25, 122-126 (2012). HPTLC of 4-tert-butyl, 4-methoxydibenzoylmethane along with a photostabilizer on silica gel, then exposed to solar simulated sunlight and developed with n-hexane - ethyl acetate 9:1. Detection under UV 366 nm. Quantitative determination of the amount of sunscreen left after solar exposure by absorbance measurement at 357 nm.

CBS 107, 5-7 (2011). HPTLC of coenzyme Q10 in toluene extracts of soft gel capsules on silica gel (pre-washed by development from both sides with methanol) with toluene in the horizontal developing chamber from both sides. Detection under UV 254 nm. The hRf value of coenzyme Q10 is 20. Quantitative absorption measurement at 282 nm, evaluation via peak height. Linearity was in the range of 20-50 ng/band. Polynomial calibration ranged 20-150 ng/band. The parallel analysis of 60 samples (10 samples each from 6 batches) and 12 standards required only 86 min. The test for content uniformity was performed with 10 samples according to the European Pharmacopoeia and the USP 34 and the requirements were met.