Asian Journal of Chemistry 23(1), 469-470 (2011). Several herbal formulations were analyzed for gallic acid contents. Tablets were powdered, subjected to hydrolysis by refluxing with 10 % HCl, filtrated and extracted with chloroform. Acidic aqueous extracts were concentrated and the residue was taken up in methanol. TLC on silica gel with ethyl acetate - formic acid 85:11. Gallic acid was observed at an hRf value of 89. Densitometric quantification of gallic acid at 272 nm. The method was linear in the range of 100-3000 ng/band. The method was suitable for analysis of formulations without interference from excipients. Gallic acid contents of different tablet samples varied from 0.06-0.15 % w/w.

International Journal of Pharmaceutical Sciences Review and Research 2(2), 35-39 (2010). TLC on silica gel with methanol - chloroform 1:6. The hRf value was 38 and 68 for ramipril and telmisartan respectively. Densitometric evaluation at 210 nm. The method was linear in the range of 300-3000 ng/band and 500-4000 ng/band for ramipril and telmisartan respectively. The recovery was 98-102 %. The sample was subjected to different stress conditions (acid, base, oxidative, heat, photolytic) and all the degradation products were well separated from drug.

Quim. Nova. 34, 330-334 (2011). TLC of rosmarinic acid in preparations of Rosmarinus officinalis on silica gel with acetone – formic acid – methylene chloride 50:17:170. Detection under UV 366 nm. Quantitative determination by solid state differential pulse voltammetry (DPV). Linearity was between 0.694x10-3 to 0.526x10-3 mol/L. The limits of detection and quantification were 1.2x10-5 and 3.6x10-5 mol/L, respectively. The intermediate/interday/intraday precisions were 3.03 % and 2.2 %, respectively. Recovery (by standard addition) was 96.3 % for rosmarinic acid. The method presented high recovery levels compared to an HPLC method.

62nd Indian Pharmaceutical Congress Abstract No. F-233 (2010). TLC of metoprolol and ramipril on silica gel with methanol – toluene – ethyl acetate – ammonia 25:30:50:7. Quantitative determination by absorbance measurement at 209 nm. The hRf values of metoprolol and ramipril were 67 and 37, respectively. The reliability of the method was assessed by evaluation of linearity (2-12 µg/band for metoprolol and 0.2-1.2 µg/band for ramipril).

Asian Journal of Chemistry 23 (5), 2098-2100 (2011). HPTLC of glycyrrhizic acid in herbal formulation on silica gel with chloroform - glacial acetic acid - methanol - water 15:8:3:2. The hRf value of glycyrrhizic acid was 28. Quantitative evaluation by absorbance measurement at 254 nm. The method was found to be linear in the range of 100-500 ng/band with average recovery between 99-102 %.

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.

Lipids 18, 896-899 (1983). Two-dimensional separation of phospholipids on silica with 1) chloroform - methanol - NH3 65:25:5., 2) chloroform - acetone - methanol - acetic acid - water 10:4:2:3:1; visualizing under UV after spraying with 2',7'-dlchlorofluoresceine; removing the fractions by scraping and identification by co-chromatography with authentic standards (one-dimensionally); plasmalogenes can be identified by exposing the plate to HCl (after the first development).

J. Chromatogr. 387, 323-331 (1987). HPTLC and HETLC of various phospholipids and glycolipids on silica with ethanol - chloroform - NH3 50:6:6, methyl acetate - propanol - chloroform - methanol - 0.25% aq. potassium chloride 25:25:28:10:7, chloroform - methanol - acetic acid - formic acid - water 35:15:6:2:1 or hexane - propyl ether - acetic acid 65:35:2. Detection with 10% cupric sulfate or 3l % cupric acetate in 8 % phosphoric acid. Densitometry at 525 nm. Procedure useful for the determination of the lipid compositions of small amounts of tissues or of samples where the total lipid content is low.