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The main aim of the present investigation was to study the retention and separation of eight nucleotides with the use of seven stationary phases in RP HPLC mode. Two octadecyl columns were used; however, aminopropyl, alkylamide, cholesterol, alkyl-phosphate, and phenyl were also studied. Special attention was paid to the mobile phase buffer pH, since it appears that this factor is very influential in the case of chromatographic separation of nucleotides. The retention of nucleotides was greater for mobile phase pH?4.0 in comparison with pH?7.0 (except for octadecyl and phenyl packing). This is a consequence of protonization of polar groups present on the stationary phase surface. It was proved that aminopropyl, alkyl phosphate, alkylamide packing materials are not suitable for the resolution of nucleotides. On the other hand, cholesterol and phenyl stationary phases are alternatives for conventional octadecyl phases. Application of cholesterol packing allows separation of small, polar nucleotides, which is impossible to achieve in the case of octadecyl phase. Moreover, a phenyl support allows separation of nucleotides in a shorter time in comparison with octadecyl packing. 相似文献
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Analysis of normal and modified nucleosides in urine samples by high‐performance liquid chromatography with different stationary phases
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The main aim of the present work was to study the retention behavior and quantification of nine nucleosides with the use of octadecyl, alkylamide, cholesterol and alkyl‐phosphate stationary phases. The influence of organic solvent and buffer concentration on the separation of these compounds was under investigation. The retention factor had the highest values for the octadecyl and cholesterol packing materials. Complete separation of all the studied nucleosides was achieved in case of cholesterol stationary phase. The optimized separation method was applied for the quantification of nucleosides in the urine samples. Calibration plots showed good linearity (R2 > 0.999) and the limits of detection were in a range of 0.3–0.5 µg/mL, while the limits of quantitation were >0.9 µg/mL. Accuracy was in the range of 5–11%. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Chromatographic analysis of ionic liquids on different types of packings offers interesting possibility to determine their retention mechanism. As a consequence, the major interactions between stationary phase ligands and analyzed chemical entities can be defined. The main aim of this work was to analyze cations of ionic liquids on chemically bonded stationary phases with specific structural properties. The attempt to predict the main interactions between positive ions of ionic liquids and stationary phase ligands was undertaken. For that purpose, butyl, octyl, octadecyl, phenyl, aryl, mixed, alkylamide, and cholesterolic packings were chosen and applied to the analysis of six most commonly used ionic liquids' cations. Obtained results indicate mainly dispersive and pi-pi type of interaction part in the retention mechanism of analyzed compounds. 相似文献