High-performance thin-layer chromatography and three-dimensional image analysis for the determination of rutin in pharmaceutical preparations.

A novel HPTLC method was developed for fast and simple quantitative determination of rutin in pharmaceutical preparations. The proposed method combines the advantages of HPTLC with the comfort and the convenience of digital processing of images. For the separation of rutin, silica gel with attached amino groups was used as the stationary phase and ethyl acetate-formic acid-methanol-water (10 + 0.9 + 1.1 + 1.7, v/v/v/v) as the mobile phase. The chromatographic plate was sprayed with 2-aminoethyldiphenyl borate solution for visual detection of the spots. For the construction of a three-dimensional chromatogram, Melanie 7.0 software was used together with an HP flatbed scanner that allowed capture of the images on chromatographic plates. The calibration curve was linear within the range of 0.95-4.78 microg/spot with an r value of 0.9984. The RSD for six replicates at three concentration levels was less than 3%, while the recovery was between 97.28 and 103.27%. The proposed method was found to be simple, precise, sensitive, and accurate and has been applied for the determination of rutin in two commercial drugs. The results were compared with the results of other techniques that generate bidimensional chromatograms and validated by UV-Vis spectrophotometry.

Quantitative determination of some food dyes using digital processing of images obtained by thin-layer chromatography.

A high-performance thin-layer chromatographic method combined with image processing of scanned chromatograms was developed for the determination of some food dyes (tartrazine, azorubine and Sunset Yellow) in different products. Porous silica gel with 3-aminopropyl functional groups attached to the matrix was used as stationary phase and a mixture of isopropanol, diethyl ether and ammonia (2:2:1, v/v/v) formed the mobile phase. Quantitative evaluation was performed using special-purpose software. The linearity of the analytical procedure was sustained by the numerical parameters such as correlation coefficient (0.9952-0.9980) and standard error of determination (0.03-0.20). The limits of detection were found to be within the range of 5.21-9.34 ng/spot, and the limits of quantification between 10.21 and 18.09 ng/spot. Recovery studies performed on two levels of concentration gave values between 96.39 and 102.76%. These results show that the regression approach provides rigorous and realistic detection and quantification limits and as a consequence can be routinely applied to other analytical systems. This method does not require expensive analytical instruments compared with classical densitometry and provides a reliable quantitative evaluation with minimum of time.

Multivariate analysis of reflectance spectra from propolis: geographical variation in Romanian samples.

The present study described reflectance spectroscopy as a suitable analytical tool to discriminate the floral origin of 39 Romanian propolis samples. Relevant differences between the UV-vis reflectance spectra of the investigated propolis samples within the 220-850nm spectral range were found. The results obtained applying cluster analysis, principal component analysis and linear discriminant analysis to the digitized data of zero order, zero order normalized and first order derivative spectra support the reliability of this technique. In addition, the application of the linear discriminant analysis to the score matrices corresponding to the first principal components appeared to be an illuminating solution. Generally, the samples have been assigned to two large groups in a good agreement with their vegetal sampling location, samples originating from predominant forest area and samples originating from meadows. Within the first group, two subgroups were identified according to the dominant type of the forest, deciduous or resinous, while within the last group three subgroups were found according to the extend and variety of the meadow.