Chinese J. Chromatogr. 32 (3), 242-247 (2014). Definition of novel molecular connectivity indices and calculation of the indices for 18 chiral hydroxyl acids and amino acids, based on Kier’s molecular connectivity indices and conjugated matrix. Study of the quantitative structure-retention index relationship (QSRR) between the retention index of the chiral organic acids and the chiral connectivity indices by multivariate statistical regression. The best four-parameter QSRR model was set up through leaps-and-bounds regression analysis. The traditional correlation coefficient and the cross-validation correlation coefficient of leave-one-out were given, respectively. The results demonstrated that the model was highly reliable and had good predictive ability from the statistical point of view. From the parameters of the model, it is known that the dominant influence factors on the retention index were the two-dimensional molecular structure characteristics and the space factors such as the chiral characteristics, the flexibility and the puckered degree of the molecules of the chiral organic acids. The results also indicated that the introduced chiral connectivity indices had good rationality and validity for the characterization of the retention indices for the chiral organic acids, thus, provided an effective method for predicting the retention indices of chiral organic acids.

J. Chromatogr. 448, 345-354 (1988). Reversed-phase TLC of a variety of racemic compounds on octadecyl-bonded silica with mobile phases containing highly concentrated solutions of ß-cyclodextrin. Detection under UV 254 nm. Densitometry at the wavelength of maximum absorbance for each compound.

J. Chromatogr. 504, 450-455 (1990). TLC of reaction products in synthesis of modified phenylalanine and tyrosine derivatives on chiralplate with acetonitrile - methanol - water 4:1:1. Also, chiral TLC separations for the determination of amino acid configuration of synthetic peptide analogs which were prepared from racemic aromatic amino acids.

Chromatographia 35, 679-680 (1993). TLC of (±)-hyoscyamine catropine and (±)-colchicine on silica, impregnated with an optically active acid, L-aspartic acid (0.03%), as chiral selector, with butanol - chloroform - acetic acid - water 3:6:4:1 as mobile phase. Detection by exposure to iodine vapor.

J. Planar Chromatogr. 7, 376-381 (1994). Investigation of the chromatographic behavior of several racemates and pure optical isomers on commercially available and home-made acetylated cellulose plates developed with aqueous organic mobile phases containing ethanol or 2-propanol. The resolution of the enantiomers is highly dependent on the type of cellulose triacetate (acetyl content and structure of the adsorbent), the concentration of organic solvent and the temperature.

J. Planar Chromatogr. 10, 4-9 (1997). Description of a complete resolution of the cis and trans isomers of capsaicin ; the method also gave good resolution from other capsaicin analogues, enabling spectrodensitometric determination of the trans-capsaicin present. HPTLC of cis- and trans-capsaicin (and homodihydrocapsaicin, dihydro-capsaicin) on RP-18 W silica impregnated with 1.5% methanolic silver nitrate solution or on non-impregnated plates and an eluent containing silver nitrate. After application of the samples and drying at 70°C for 5 min, the non-impregnated plates were developed in a fully vapor-saturated N-chamber with methanol - water 1:1 + 1.5% silver nitrate. Visualization by immersion for 2 s in a 0.1% ethanolic 2,6-dichloroquinone-4-chlorimide solution. Quantification by densitometry at 425 nm. Detection limits using iodine vapor and 2,6-dichloroquinone-4-chlorimide were 1000 ng and 60 ng, respectively.

Chinese J. Anal. Chem. (Fenxi Huaxue) 28 (3), 349-352 (2000). Preparation of the title material and determination of the characteristics by IR, elemental analysis and thermal analysis, showing that the derivatized b-cyclodextrin bonded phase was stable and suitable for both normal and reversed phases. Demonstration of the use of the bonded phase in chiral separation of chiral drugs with hexane - isopropanol - 1% triethyl ammonium acetate and acetonitrile - methanol - 1% triethyl ammonium acetate in different proportions, and six chiral drugs being completely resolved.

J. Planar Chromatogr. 18, 294-299 (2005). TLC of (+/-)-metoprolol tartrate and (-)-alprenolol tartrate on silica gel, with concentrating zone, on RP-18, on LiChrospher silica gel and on alumina, previously impregnated with the mobile phase (ethanol - water 7:3, containing D-(-)-tartaric acid as chiral selector). Detection under UV light at 254 nm and densitometric scanning at 230 nm. Direct separation of the enantiomers of (+/-)-metoprolol tartrate was achieved.